Now that we have properly split load/store instruction emulation and generic
instruction emulation, we can move the generic one from kvm.ko to kvm-pr.ko
on book3s_64.
This reduces the attack surface and amount of code loaded on HV KVM kernels.
Signed-off-by: Alexander Graf <agraf@suse.de>
DCR handling was only needed for 440 KVM. Since we removed it, we can also
remove handling of DCR accesses.
Signed-off-by: Alexander Graf <agraf@suse.de>
We're going to implement guest code interpretation in KVM for some rare
corner cases. This code needs to be able to inject data and instruction
faults into the guest when it encounters them.
Expose generic APIs to do this in a reasonably subarch agnostic fashion.
Signed-off-by: Alexander Graf <agraf@suse.de>
Today the instruction emulator can get called via 2 separate code paths. It
can either be called by MMIO emulation detection code or by privileged
instruction traps.
This is bad, as both code paths prepare the environment differently. For MMIO
emulation we already know the virtual address we faulted on, so instructions
there don't have to actually fetch that information.
Split out the two separate use cases into separate files.
Signed-off-by: Alexander Graf <agraf@suse.de>
We use kvmppc_ld and kvmppc_st to emulate load/store instructions that may as
well access the magic page. Special case it out so that we can properly access
it.
Signed-off-by: Alexander Graf <agraf@suse.de>
We have a nice and handy helper to read from guest physical address space,
so we should make use of it in kvmppc_ld as we already do for its counterpart
in kvmppc_st.
Signed-off-by: Alexander Graf <agraf@suse.de>
We have enough common infrastructure now to resolve GVA->GPA mappings at
runtime. With this we can move our book3s specific helpers to load / store
in guest virtual address space to common code as well.
Signed-off-by: Alexander Graf <agraf@suse.de>
We have a nice API to find the translated GPAs of a GVA including protection
flags. So far we only use it on Book3S, but there's no reason the same shouldn't
be used on BookE as well.
Implement a kvmppc_xlate() version for BookE and clean it up to make it more
readable in general.
Signed-off-by: Alexander Graf <agraf@suse.de>
When calculating the lower bits of AVA field, use the shift
count based on the base page size. Also add the missing segment
size and remove stale comment.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
With Book3S KVM we can create both PR and HV VMs in parallel on the same
machine. That gives us new challenges on the CAPs we return - both have
different capabilities.
When we get asked about CAPs on the kvm fd, there's nothing we can do. We
can try to be smart and assume we're running HV if HV is available, PR
otherwise. However with the newly added VM CHECK_EXTENSION we can now ask
for capabilities directly on a VM which knows whether it's PR or HV.
With this patch I can successfully expose KVM PVINFO data to user space
in the PR case, fixing magic page mapping for PAPR guests.
Signed-off-by: Alexander Graf <agraf@suse.de>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
In preparation to make the check_extension function available to VM scope
we add a struct kvm * argument to the function header and rename the function
accordingly. It will still be called from the /dev/kvm fd, but with a NULL
argument for struct kvm *.
Signed-off-by: Alexander Graf <agraf@suse.de>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
The POWER8 processor has a Micro Partition Prefetch Engine, which is
a fancy way of saying "has way to store and load contents of L2 or
L2+MRU way of L3 cache". We initiate the storing of the log (list of
addresses) using the logmpp instruction and start restore by writing
to a SPR.
The logmpp instruction takes parameters in a single 64bit register:
- starting address of the table to store log of L2/L2+L3 cache contents
- 32kb for L2
- 128kb for L2+L3
- Aligned relative to maximum size of the table (32kb or 128kb)
- Log control (no-op, L2 only, L2 and L3, abort logout)
We should abort any ongoing logging before initiating one.
To initiate restore, we write to the MPPR SPR. The format of what to write
to the SPR is similar to the logmpp instruction parameter:
- starting address of the table to read from (same alignment requirements)
- table size (no data, until end of table)
- prefetch rate (from fastest possible to slower. about every 8, 16, 24 or
32 cycles)
The idea behind loading and storing the contents of L2/L3 cache is to
reduce memory latency in a system that is frequently swapping vcores on
a physical CPU.
The best case scenario for doing this is when some vcores are doing very
cache heavy workloads. The worst case is when they have about 0 cache hits,
so we just generate needless memory operations.
This implementation just does L2 store/load. In my benchmarks this proves
to be useful.
Benchmark 1:
- 16 core POWER8
- 3x Ubuntu 14.04LTS guests (LE) with 8 VCPUs each
- No split core/SMT
- two guests running sysbench memory test.
sysbench --test=memory --num-threads=8 run
- one guest running apache bench (of default HTML page)
ab -n 490000 -c 400 http://localhost/
This benchmark aims to measure performance of real world application (apache)
where other guests are cache hot with their own workloads. The sysbench memory
benchmark does pointer sized writes to a (small) memory buffer in a loop.
In this benchmark with this patch I can see an improvement both in requests
per second (~5%) and in mean and median response times (again, about 5%).
The spread of minimum and maximum response times were largely unchanged.
benchmark 2:
- Same VM config as benchmark 1
- all three guests running sysbench memory benchmark
This benchmark aims to see if there is a positive or negative affect to this
cache heavy benchmark. Although due to the nature of the benchmark (stores) we
may not see a difference in performance, but rather hopefully an improvement
in consistency of performance (when vcore switched in, don't have to wait
many times for cachelines to be pulled in)
The results of this benchmark are improvements in consistency of performance
rather than performance itself. With this patch, the few outliers in duration
go away and we get more consistent performance in each guest.
benchmark 3:
- same 3 guests and CPU configuration as benchmark 1 and 2.
- two idle guests
- 1 guest running STREAM benchmark
This scenario also saw performance improvement with this patch. On Copy and
Scale workloads from STREAM, I got 5-6% improvement with this patch. For
Add and triad, it was around 10% (or more).
benchmark 4:
- same 3 guests as previous benchmarks
- two guests running sysbench --memory, distinctly different cache heavy
workload
- one guest running STREAM benchmark.
Similar improvements to benchmark 3.
benchmark 5:
- 1 guest, 8 VCPUs, Ubuntu 14.04
- Host configured with split core (SMT8, subcores-per-core=4)
- STREAM benchmark
In this benchmark, we see a 10-20% performance improvement across the board
of STREAM benchmark results with this patch.
Based on preliminary investigation and microbenchmarks
by Prerna Saxena <prerna@linux.vnet.ibm.com>
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
No code changes, just split it out to a function so that with the addition
of micro partition prefetch buffer allocation (in subsequent patch) looks
neater and doesn't require excessive indentation.
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
At present, kvmppc_ld calls kvmppc_xlate, and if kvmppc_xlate returns
any error indication, it returns -ENOENT, which is taken to mean an
HPTE not found error. However, the error could have been a segment
found (no SLB entry) or a permission error. Similarly,
kvmppc_pte_to_hva currently does permission checking, but any error
from it is taken by kvmppc_ld to mean that the access is an emulated
MMIO access. Also, kvmppc_ld does no execute permission checking.
This fixes these problems by (a) returning any error from kvmppc_xlate
directly, (b) moving the permission check from kvmppc_pte_to_hva
into kvmppc_ld, and (c) adding an execute permission check to kvmppc_ld.
This is similar to what was done for kvmppc_st() by commit 82ff911317c3
("KVM: PPC: Deflect page write faults properly in kvmppc_st").
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
This does for PR KVM what c9438092ca ("KVM: PPC: Book3S HV: Take SRCU
read lock around kvm_read_guest() call") did for HV KVM, that is,
eliminate a "suspicious rcu_dereference_check() usage!" warning by
taking the SRCU lock around the call to kvmppc_rtas_hcall().
It also fixes a return of RESUME_HOST to return EMULATE_FAIL instead,
since kvmppc_h_pr() is supposed to return EMULATE_* values.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: stable@vger.kernel.org
Signed-off-by: Alexander Graf <agraf@suse.de>
Unfortunately, the LPCR got defined as a 32-bit register in the
one_reg interface. This is unfortunate because KVM allows userspace
to control the DPFD (default prefetch depth) field, which is in the
upper 32 bits. The result is that DPFD always get set to 0, which
reduces performance in the guest.
We can't just change KVM_REG_PPC_LPCR to be a 64-bit register ID,
since that would break existing userspace binaries. Instead we define
a new KVM_REG_PPC_LPCR_64 id which is 64-bit. Userspace can still use
the old KVM_REG_PPC_LPCR id, but it now only modifies those fields in
the bottom 32 bits that userspace can modify (ILE, TC and AIL).
If userspace uses the new KVM_REG_PPC_LPCR_64 id, it can modify DPFD
as well.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: stable@vger.kernel.org
Signed-off-by: Alexander Graf <agraf@suse.de>
The 440 target hasn't been properly functioning for a few releases and
before I was the only one who fixes a very serious bug that indicates to
me that nobody used it before either.
Furthermore KVM on 440 is slow to the extent of unusable.
We don't have to carry along completely unused code. Remove 440 and give
us one less thing to worry about.
Signed-off-by: Alexander Graf <agraf@suse.de>
We now support SPRG9 for guest, so also add a one reg interface for same
Note: Changes are in bookehv code only as we do not have SPRG9 on booke-pr.
Signed-off-by: Bharat Bhushan <Bharat.Bhushan@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
SPRN_SPRG is used by debug interrupt handler, so this is required for
debug support.
Signed-off-by: Bharat Bhushan <Bharat.Bhushan@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
On book3e, KVM uses load external pid (lwepx) dedicated instruction to read
guest last instruction on the exit path. lwepx exceptions (DTLB_MISS, DSI
and LRAT), generated by loading a guest address, needs to be handled by KVM.
These exceptions are generated in a substituted guest translation context
(EPLC[EGS] = 1) from host context (MSR[GS] = 0).
Currently, KVM hooks only interrupts generated from guest context (MSR[GS] = 1),
doing minimal checks on the fast path to avoid host performance degradation.
lwepx exceptions originate from host state (MSR[GS] = 0) which implies
additional checks in DO_KVM macro (beside the current MSR[GS] = 1) by looking
at the Exception Syndrome Register (ESR[EPID]) and the External PID Load Context
Register (EPLC[EGS]). Doing this on each Data TLB miss exception is obvious
too intrusive for the host.
Read guest last instruction from kvmppc_load_last_inst() by searching for the
physical address and kmap it. This address the TODO for TLB eviction and
execute-but-not-read entries, and allow us to get rid of lwepx until we are
able to handle failures.
A simple stress benchmark shows a 1% sys performance degradation compared with
previous approach (lwepx without failure handling):
time for i in `seq 1 10000`; do /bin/echo > /dev/null; done
real 0m 8.85s
user 0m 4.34s
sys 0m 4.48s
vs
real 0m 8.84s
user 0m 4.36s
sys 0m 4.44s
A solution to use lwepx and to handle its exceptions in KVM would be to temporary
highjack the interrupt vector from host. This imposes additional synchronizations
for cores like FSL e6500 that shares host IVOR registers between hardware threads.
This optimized solution can be later developed on top of this patch.
Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
On book3e, guest last instruction is read on the exit path using load
external pid (lwepx) dedicated instruction. This load operation may fail
due to TLB eviction and execute-but-not-read entries.
This patch lay down the path for an alternative solution to read the guest
last instruction, by allowing kvmppc_get_lat_inst() function to fail.
Architecture specific implmentations of kvmppc_load_last_inst() may read
last guest instruction and instruct the emulation layer to re-execute the
guest in case of failure.
Make kvmppc_get_last_inst() definition common between architectures.
Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
In the context of replacing kvmppc_ld() function calls with a version of
kvmppc_get_last_inst() which allow to fail, Alex Graf suggested this:
"If we get EMULATE_AGAIN, we just have to make sure we go back into the guest.
No need to inject an ISI into the guest - it'll do that all by itself.
With an error returning kvmppc_get_last_inst we can just use completely
get rid of kvmppc_read_inst() and only use kvmppc_get_last_inst() instead."
As a intermediate step get rid of kvmppc_read_inst() and only use kvmppc_ld()
instead.
Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
The commit 1d628af7 "add load inst fixup" made an attempt to handle
failures generated by reading the guest current instruction. The fixup
code that was added works by chance hiding the real issue.
Load external pid (lwepx) instruction, used by KVM to read guest
instructions, is executed in a subsituted guest translation context
(EPLC[EGS] = 1). In consequence lwepx's TLB error and data storage
interrupts need to be handled by KVM, even though these interrupts
are generated from host context (MSR[GS] = 0) where lwepx is executed.
Currently, KVM hooks only interrupts generated from guest context
(MSR[GS] = 1), doing minimal checks on the fast path to avoid host
performance degradation. As a result, the host kernel handles lwepx
faults searching the faulting guest data address (loaded in DEAR) in
its own Logical Partition ID (LPID) 0 context. In case a host translation
is found the execution returns to the lwepx instruction instead of the
fixup, the host ending up in an infinite loop.
Revert the commit "add load inst fixup". lwepx issue will be addressed
in a subsequent patch without needing fixup code.
Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
kvmppc_set_epr() is already defined in asm/kvm_ppc.h, So
rename and move get_epr helper function to same file.
Signed-off-by: Bharat Bhushan <Bharat.Bhushan@freescale.com>
[agraf: remove duplicate return]
Signed-off-by: Alexander Graf <agraf@suse.de>
Use kvmppc_set_sprg[0-7]() and kvmppc_get_sprg[0-7]() helper
functions
Signed-off-by: Bharat Bhushan <Bharat.Bhushan@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Add and use kvmppc_set_esr() and kvmppc_get_esr() helper functions
Signed-off-by: Bharat Bhushan <Bharat.Bhushan@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Use kvmppc_set_srr0/srr1() and kvmppc_get_srr0/srr1() helper functions
Signed-off-by: Bharat Bhushan <Bharat.Bhushan@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
The magic page is defined as a 4k page of per-vCPU data that is shared
between the guest and the host to accelerate accesses to privileged
registers.
However, when the host is using 64k page size granularity we weren't quite
as strict about that rule anymore. Instead, we partially treated all of the
upper 64k as magic page and mapped only the uppermost 4k with the actual
magic contents.
This works well enough for Linux which doesn't use any memory in kernel
space in the upper 64k, but Mac OS X got upset. So this patch makes magic
page actually stay in a 4k range even on 64k page size hosts.
This patch fixes magic page usage with Mac OS X (using MOL) on 64k PAGE_SIZE
hosts for me.
Signed-off-by: Alexander Graf <agraf@suse.de>
Today we handle split real mode by mapping both instruction and data faults
into a special virtual address space that only exists during the split mode
phase.
This is good enough to catch 32bit Linux guests that use split real mode for
copy_from/to_user. In this case we're always prefixed with 0xc0000000 for our
instruction pointer and can map the user space process freely below there.
However, that approach fails when we're running KVM inside of KVM. Here the 1st
level last_inst reader may well be in the same virtual page as a 2nd level
interrupt handler.
It also fails when running Mac OS X guests. Here we have a 4G/4G split, so a
kernel copy_from/to_user implementation can easily overlap with user space
addresses.
The architecturally correct way to fix this would be to implement an instruction
interpreter in KVM that kicks in whenever we go into split real mode. This
interpreter however would not receive a great amount of testing and be a lot of
bloat for a reasonably isolated corner case.
So I went back to the drawing board and tried to come up with a way to make
split real mode work with a single flat address space. And then I realized that
we could get away with the same trick that makes it work for Linux:
Whenever we see an instruction address during split real mode that may collide,
we just move it higher up the virtual address space to a place that hopefully
does not collide (keep your fingers crossed!).
That approach does work surprisingly well. I am able to successfully run
Mac OS X guests with KVM and QEMU (no split real mode hacks like MOL) when I
apply a tiny timing probe hack to QEMU. I'd say this is a win over even more
broken split real mode :).
Signed-off-by: Alexander Graf <agraf@suse.de>
When a page lookup failed because we're not allowed to write to the page, we
should not overwrite that value with another lookup on the second PTEG which
will return "page not found". Instead, we should just tell the caller that we
had a permission problem.
This fixes Mac OS X guests looping endlessly in page lookup code for me.
Signed-off-by: Alexander Graf <agraf@suse.de>
When we have a page that we're not allowed to write to, xlate() will already
tell us -EPERM on lookup of that page. With the code as is we change it into
a "page missing" error which a guest may get confused about. Instead, just
tell the caller about the -EPERM directly.
This fixes Mac OS X guests when run with DCBZ32 emulation.
Signed-off-by: Alexander Graf <agraf@suse.de>
For FSL e6500 core the kernel uses power management SPR register (PWRMGTCR0)
to enable idle power down for cores and devices by setting up the idle count
period at boot time. With the host already controlling the power management
configuration the guest could simply benefit from it, so emulate guest request
as a general store.
Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Now that we've fixed all the issues that HV KVM code had on little endian
hosts, we can enable it in the kernel configuration for users to play with.
Signed-off-by: Alexander Graf <agraf@suse.de>
For code that doesn't live in modules we can just branch to the real function
names, giving us compatibility with ABIv1 and ABIv2.
Do this for the compiled-in code of HV KVM.
Signed-off-by: Alexander Graf <agraf@suse.de>
On the exit path from the guest we check what type of interrupt we received
if we received one. This means we're doing hardware access to the XICS interrupt
controller.
However, when running on a little endian system, this access is byte reversed.
So let's make sure to swizzle the bytes back again and virtually make XICS
accesses big endian.
Signed-off-by: Alexander Graf <agraf@suse.de>
Some data structures are always stored in big endian. Among those are the LPPACA
fields as well as the shadow slb. These structures might be shared with a
hypervisor.
So whenever we access those fields, make sure we do so in big endian byte order.
Signed-off-by: Alexander Graf <agraf@suse.de>
There are a few shared data structures between the host and the guest. Most
of them get registered through the VPA interface.
These data structures are defined to always be in big endian byte order, so
let's make sure we always access them in big endian.
Signed-off-by: Alexander Graf <agraf@suse.de>
When running on an LE host all data structures are kept in little endian
byte order. However, the HTAB still needs to be maintained in big endian.
So every time we access any HTAB we need to make sure we do so in the right
byte order. Fix up all accesses to manually byte swap.
Signed-off-by: Alexander Graf <agraf@suse.de>
Tlb search operation used for victim hint relies on the default tlb set by the
host. When hardware tablewalk support is enabled in the host, the default tlb is
TLB1 which leads KVM to evict the bolted entry. Set and restore the default tlb
when searching for victim hint.
Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Reviewed-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
This adds support for the H_SET_MODE hcall. This hcall is a
multiplexer that has several functions, some of which are called
rarely, and some which are potentially called very frequently.
Here we add support for the functions that set the debug registers
CIABR (Completed Instruction Address Breakpoint Register) and
DAWR/DAWRX (Data Address Watchpoint Register and eXtension),
since they could be updated by the guest as often as every context
switch.
This also adds a kvmppc_power8_compatible() function to test to see
if a guest is compatible with POWER8 or not. The CIABR and DAWR/X
only exist on POWER8.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
This adds code to check that when the KVM_CAP_PPC_ENABLE_HCALL
capability is used to enable or disable in-kernel handling of an
hcall, that the hcall is actually implemented by the kernel.
If not an EINVAL error is returned.
This also checks the default-enabled list of hcalls and prints a
warning if any hcall there is not actually implemented.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
This provides a way for userspace controls which sPAPR hcalls get
handled in the kernel. Each hcall can be individually enabled or
disabled for in-kernel handling, except for H_RTAS. The exception
for H_RTAS is because userspace can already control whether
individual RTAS functions are handled in-kernel or not via the
KVM_PPC_RTAS_DEFINE_TOKEN ioctl, and because the numeric value for
H_RTAS is out of the normal sequence of hcall numbers.
Hcalls are enabled or disabled using the KVM_ENABLE_CAP ioctl for the
KVM_CAP_PPC_ENABLE_HCALL capability on the file descriptor for the VM.
The args field of the struct kvm_enable_cap specifies the hcall number
in args[0] and the enable/disable flag in args[1]; 0 means disable
in-kernel handling (so that the hcall will always cause an exit to
userspace) and 1 means enable. Enabling or disabling in-kernel
handling of an hcall is effective across the whole VM.
The ability for KVM_ENABLE_CAP to be used on a VM file descriptor
on PowerPC is new, added by this commit. The KVM_CAP_ENABLE_CAP_VM
capability advertises that this ability exists.
When a VM is created, an initial set of hcalls are enabled for
in-kernel handling. The set that is enabled is the set that have
an in-kernel implementation at this point. Any new hcall
implementations from this point onwards should not be added to the
default set without a good reason.
No distinction is made between real-mode and virtual-mode hcall
implementations; the one setting controls them both.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
On vcpu schedule, the condition checked for tlb pollution is too loose.
The tlb entries of a vcpu become polluted (vs stale) only when a different
vcpu within the same logical partition runs in-between. Optimize the tlb
invalidation condition keeping last_vcpu per logical partition id.
With the new invalidation condition, a guest shows 4% performance improvement
on P5020DS while running a memory stress application with the cpu oversubscribed,
the other guest running a cpu intensive workload.
Guest - old invalidation condition
real 3.89
user 3.87
sys 0.01
Guest - enhanced invalidation condition
real 3.75
user 3.73
sys 0.01
Host
real 3.70
user 1.85
sys 0.00
The memory stress application accesses 4KB pages backed by 75% of available
TLB0 entries:
char foo[ENTRIES][4096] __attribute__ ((aligned (4096)));
int main()
{
char bar;
int i, j;
for (i = 0; i < ITERATIONS; i++)
for (j = 0; j < ENTRIES; j++)
bar = foo[j][0];
return 0;
}
Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Reviewed-by: Scott Wood <scottwood@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
While sending sparse with endian checks over the code base, it triggered at
some places that were missing casts or had wrong types. Fix them up.
Signed-off-by: Alexander Graf <agraf@suse.de>
We switched to ABIv2 on Little Endian systems now which gets rid of the
dotted function names. Branch to the actual functions when we see such
a system.
Signed-off-by: Alexander Graf <agraf@suse.de>
Both kvmppc_hv_entry_trampoline and kvmppc_entry_trampoline are
assembly functions that are exported to modules and also require
a valid r2.
As such we need to use _GLOBAL_TOC so we provide a global entry
point that establishes the TOC (r2).
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
To establish addressability quickly, ABIv2 requires the target
address of the function being called to be in r12.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
If we're running PR KVM in HV mode, we may get hypervisor doorbell interrupts.
Handle those the same way we treat normal doorbells.
Signed-off-by: Alexander Graf <agraf@suse.de>
When we're using PR KVM we must not allow the CPU to take interrupts
in virtual mode, as the SLB does not contain host kernel mappings
when running inside the guest context.
To make sure we get good performance for non-KVM tasks but still
properly functioning PR KVM, let's just disable AIL whenever a vcpu
is scheduled in.
This is fundamentally different from how we deal with AIL on pSeries
type machines where we disable AIL for the whole machine as soon as
a single KVM VM is up.
The reason for that is easy - on pSeries we do not have control over
per-cpu configuration of AIL. We also don't want to mess with CPU hotplug
races and AIL configuration, so setting it per CPU is easier and more
flexible.
This patch fixes running PR KVM on POWER8 bare metal for me.
Signed-off-by: Alexander Graf <agraf@suse.de>
Acked-by: Paul Mackerras <paulus@samba.org>
Writing to IC is not allowed in the privileged mode.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
virtual time base register is a per VM, per cpu register that needs
to be saved and restored on vm exit and entry. Writing to VTB is not
allowed in the privileged mode.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
[agraf: fix compile error]
Signed-off-by: Alexander Graf <agraf@suse.de>
an x86 change too and it is a regression from 3.14. As it only affects
nested virtualization and there were other changes in this area in 3.16,
I am not nominating it for 3.15-stable.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull kvm fixes from Paolo Bonzini:
"These are mostly PPC changes for 3.16-new things. However, there is
an x86 change too and it is a regression from 3.14. As it only
affects nested virtualization and there were other changes in this
area in 3.16, I am not nominating it for 3.15-stable"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: x86: Check for nested events if there is an injectable interrupt
KVM: PPC: RTAS: Do byte swaps explicitly
KVM: PPC: Book3S PR: Fix ABIv2 on LE
KVM: PPC: Assembly functions exported to modules need _GLOBAL_TOC()
PPC: Add _GLOBAL_TOC for 32bit
KVM: PPC: BOOK3S: HV: Use base page size when comparing against slb value
KVM: PPC: Book3E: Unlock mmu_lock when setting caching atttribute
These two registers are already saved in the block above. Aside from
being unnecessary, by the time we get down to the second save location
r8 no longer contains MMCR2, so we are clobbering the saved value with
PMC5.
MMCR2 primarily consists of counter freeze bits. So restoring the value
of PMC5 into MMCR2 will most likely have the effect of freezing
counters.
Fixes: 72cde5a88d ("KVM: PPC: Book3S HV: Save/restore host PMU registers that are new in POWER8")
Cc: stable@vger.kernel.org
Signed-off-by: Joel Stanley <joel@jms.id.au>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Paul Mackerras <paulus@samba.org>
Reviewed-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
A few bug fixes to make 3.16 work well with KVM on PowerPC:
- Fix ppc32 module builds
- Fix Little Endian hosts
- Fix Book3S HV HPTE lookup with huge pages in guest
- Fix BookE lock leak
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Merge tag 'signed-for-3.16' of git://github.com/agraf/linux-2.6 into kvm-master
Patch queue for 3.16 - 2014-07-08
A few bug fixes to make 3.16 work well with KVM on PowerPC:
- Fix ppc32 module builds
- Fix Little Endian hosts
- Fix Book3S HV HPTE lookup with huge pages in guest
- Fix BookE lock leak
In commit b59d9d26b we introduced implicit byte swaps for RTAS calls.
Unfortunately we messed up and didn't swizzle return values properly.
Also the old approach wasn't "sparse" compatible - we were randomly
reading __be32 values on an LE system.
Let's just do all of the swizzling explicitly with byte swaps right
where values get used. That way we can at least catch bugs using sparse.
This patch fixes XICS RTAS emulation on little endian hosts for me.
Signed-off-by: Alexander Graf <agraf@suse.de>
We switched to ABIv2 on Little Endian systems now which gets rid of the
dotted function names. Branch to the actual functions when we see such
a system.
Signed-off-by: Alexander Graf <agraf@suse.de>
Both kvmppc_hv_entry_trampoline and kvmppc_entry_trampoline are
assembly functions that are exported to modules and also require
a valid r2.
As such we need to use _GLOBAL_TOC so we provide a global entry
point that establishes the TOC (r2).
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
We use time base for PURR and SPURR emulation with PR KVM since we
are emulating a single threaded core. When using time base
we need to make sure that we don't accumulate time spent in the host
in PURR and SPURR value.
Also we don't need to emulate mtspr because both the registers are
hypervisor resource.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
With guests supporting Multiple page size per segment (MPSS),
hpte_page_size returns the actual page size used. Add a new function to
return base page size and use that to compare against the the page size
calculated from SLB. Without this patch a hpte lookup can fail since
we are comparing wrong page size in kvmppc_hv_find_lock_hpte.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
The patch 08c9a188d0
kvm: powerpc: use caching attributes as per linux pte
do not handle properly the error case, letting mmu_lock locked. The lock
will further generate a RCU stall from kvmppc_e500_emul_tlbwe() caller.
In case of an error go to out label.
Signed-off-by: Mihai Caraman <mihai.caraman@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Currently we forward MCEs to guest which have been recovered by guest.
And for unhandled errors we do not deliver the MCE to guest. It looks like
with no support of FWNMI in qemu, guest just panics whenever we deliver the
recovered MCEs to guest. Also, the existig code used to return to host for
unhandled errors which was casuing guest to hang with soft lockups inside
guest and makes it difficult to recover guest instance.
This patch now forwards all fatal MCEs to guest causing guest to crash/panic.
And, for recovered errors we just go back to normal functioning of guest
instead of returning to host. This fixes soft lockup issues in guest.
This patch also fixes an issue where guest MCE events were not logged to
host console.
Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Pull powerpc updates from Ben Herrenschmidt:
"Here is the bulk of the powerpc changes for this merge window. It got
a bit delayed in part because I wasn't paying attention, and in part
because I discovered I had a core PCI change without a PCI maintainer
ack in it. Bjorn eventually agreed it was ok to merge it though we'll
probably improve it later and I didn't want to rebase to add his ack.
There is going to be a bit more next week, essentially fixes that I
still want to sort through and test.
The biggest item this time is the support to build the ppc64 LE kernel
with our new v2 ABI. We previously supported v2 userspace but the
kernel itself was a tougher nut to crack. This is now sorted mostly
thanks to Anton and Rusty.
We also have a fairly big series from Cedric that add support for
64-bit LE zImage boot wrapper. This was made harder by the fact that
traditionally our zImage wrapper was always 32-bit, but our new LE
toolchains don't really support 32-bit anymore (it's somewhat there
but not really "supported") so we didn't want to rely on it. This
meant more churn that just endian fixes.
This brings some more LE bits as well, such as the ability to run in
LE mode without a hypervisor (ie. under OPAL firmware) by doing the
right OPAL call to reinitialize the CPU to take HV interrupts in the
right mode and the usual pile of endian fixes.
There's another series from Gavin adding EEH improvements (one day we
*will* have a release with less than 20 EEH patches, I promise!).
Another highlight is the support for the "Split core" functionality on
P8 by Michael. This allows a P8 core to be split into "sub cores" of
4 threads which allows the subcores to run different guests under KVM
(the HW still doesn't support a partition per thread).
And then the usual misc bits and fixes ..."
[ Further delayed by gmail deciding that BenH is a dirty spammer.
Google knows. ]
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (155 commits)
powerpc/powernv: Add missing include to LPC code
selftests/powerpc: Test the THP bug we fixed in the previous commit
powerpc/mm: Check paca psize is up to date for huge mappings
powerpc/powernv: Pass buffer size to OPAL validate flash call
powerpc/pseries: hcall functions are exported to modules, need _GLOBAL_TOC()
powerpc: Exported functions __clear_user and copy_page use r2 so need _GLOBAL_TOC()
powerpc/powernv: Set memory_block_size_bytes to 256MB
powerpc: Allow ppc_md platform hook to override memory_block_size_bytes
powerpc/powernv: Fix endian issues in memory error handling code
powerpc/eeh: Skip eeh sysfs when eeh is disabled
powerpc: 64bit sendfile is capped at 2GB
powerpc/powernv: Provide debugfs access to the LPC bus via OPAL
powerpc/serial: Use saner flags when creating legacy ports
powerpc: Add cpu family documentation
powerpc/xmon: Fix up xmon format strings
powerpc/powernv: Add calls to support little endian host
powerpc: Document sysfs DSCR interface
powerpc: Fix regression of per-CPU DSCR setting
powerpc: Split __SYSFS_SPRSETUP macro
arch: powerpc/fadump: Cleaning up inconsistent NULL checks
...
was a pretty active cycle for KVM. Changes include:
- a lot of s390 changes: optimizations, support for migration,
GDB support and more
- ARM changes are pretty small: support for the PSCI 0.2 hypercall
interface on both the guest and the host (the latter acked by Catalin)
- initial POWER8 and little-endian host support
- support for running u-boot on embedded POWER targets
- pretty large changes to MIPS too, completing the userspace interface
and improving the handling of virtualized timer hardware
- for x86, a larger set of changes is scheduled for 3.17. Still,
we have a few emulator bugfixes and support for running nested
fully-virtualized Xen guests (para-virtualized Xen guests have
always worked). And some optimizations too.
The only missing architecture here is ia64. It's not a coincidence
that support for KVM on ia64 is scheduled for removal in 3.17.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm into next
Pull KVM updates from Paolo Bonzini:
"At over 200 commits, covering almost all supported architectures, this
was a pretty active cycle for KVM. Changes include:
- a lot of s390 changes: optimizations, support for migration, GDB
support and more
- ARM changes are pretty small: support for the PSCI 0.2 hypercall
interface on both the guest and the host (the latter acked by
Catalin)
- initial POWER8 and little-endian host support
- support for running u-boot on embedded POWER targets
- pretty large changes to MIPS too, completing the userspace
interface and improving the handling of virtualized timer hardware
- for x86, a larger set of changes is scheduled for 3.17. Still, we
have a few emulator bugfixes and support for running nested
fully-virtualized Xen guests (para-virtualized Xen guests have
always worked). And some optimizations too.
The only missing architecture here is ia64. It's not a coincidence
that support for KVM on ia64 is scheduled for removal in 3.17"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (203 commits)
KVM: add missing cleanup_srcu_struct
KVM: PPC: Book3S PR: Rework SLB switching code
KVM: PPC: Book3S PR: Use SLB entry 0
KVM: PPC: Book3S HV: Fix machine check delivery to guest
KVM: PPC: Book3S HV: Work around POWER8 performance monitor bugs
KVM: PPC: Book3S HV: Make sure we don't miss dirty pages
KVM: PPC: Book3S HV: Fix dirty map for hugepages
KVM: PPC: Book3S HV: Put huge-page HPTEs in rmap chain for base address
KVM: PPC: Book3S HV: Fix check for running inside guest in global_invalidates()
KVM: PPC: Book3S: Move KVM_REG_PPC_WORT to an unused register number
KVM: PPC: Book3S: Add ONE_REG register names that were missed
KVM: PPC: Add CAP to indicate hcall fixes
KVM: PPC: MPIC: Reset IRQ source private members
KVM: PPC: Graciously fail broken LE hypercalls
PPC: ePAPR: Fix hypercall on LE guest
KVM: PPC: BOOK3S: Remove open coded make_dsisr in alignment handler
KVM: PPC: BOOK3S: Always use the saved DAR value
PPC: KVM: Make NX bit available with magic page
KVM: PPC: Disable NX for old magic page using guests
KVM: PPC: BOOK3S: HV: Add mixed page-size support for guest
...
On LPAR guest systems Linux enables the shadow SLB to indicate to the
hypervisor a number of SLB entries that always have to be available.
Today we go through this shadow SLB and disable all ESID's valid bits.
However, pHyp doesn't like this approach very much and honors us with
fancy machine checks.
Fortunately the shadow SLB descriptor also has an entry that indicates
the number of valid entries following. During the lifetime of a guest
we can just swap that value to 0 and don't have to worry about the
SLB restoration magic.
While we're touching the code, let's also make it more readable (get
rid of rldicl), allow it to deal with a dynamic number of bolted
SLB entries and only do shadow SLB swizzling on LPAR systems.
Signed-off-by: Alexander Graf <agraf@suse.de>
We didn't make use of SLB entry 0 because ... of no good reason. SLB entry 0
will always be used by the Linux linear SLB entry, so the fact that slbia
does not invalidate it doesn't matter as we overwrite SLB 0 on exit anyway.
Just enable use of SLB entry 0 for our shadow SLB code.
Signed-off-by: Alexander Graf <agraf@suse.de>
The code that delivered a machine check to the guest after handling
it in real mode failed to load up r11 before calling kvmppc_msr_interrupt,
which needs the old MSR value in r11 so it can see the transactional
state there. This adds the missing load.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
This adds workarounds for two hardware bugs in the POWER8 performance
monitor unit (PMU), both related to interrupt generation. The effect
of these bugs is that PMU interrupts can get lost, leading to tools
such as perf reporting fewer counts and samples than they should.
The first bug relates to the PMAO (perf. mon. alert occurred) bit in
MMCR0; setting it should cause an interrupt, but doesn't. The other
bug relates to the PMAE (perf. mon. alert enable) bit in MMCR0.
Setting PMAE when a counter is negative and counter negative
conditions are enabled to cause alerts should cause an alert, but
doesn't.
The workaround for the first bug is to create conditions where a
counter will overflow, whenever we are about to restore a MMCR0
value that has PMAO set (and PMAO_SYNC clear). The workaround for
the second bug is to freeze all counters using MMCR2 before reading
MMCR0.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Current, when testing whether a page is dirty (when constructing the
bitmap for the KVM_GET_DIRTY_LOG ioctl), we test the C (changed) bit
in the HPT entries mapping the page, and if it is 0, we consider the
page to be clean. However, the Power ISA doesn't require processors
to set the C bit to 1 immediately when writing to a page, and in fact
allows them to delay the writeback of the C bit until they receive a
TLB invalidation for the page. Thus it is possible that the page
could be dirty and we miss it.
Now, if there are vcpus running, this is not serious since the
collection of the dirty log is racy already - some vcpu could dirty
the page just after we check it. But if there are no vcpus running we
should return definitive results, in case we are in the final phase of
migrating the guest.
Also, if the permission bits in the HPTE don't allow writing, then we
know that no CPU can set C. If the HPTE was previously writable and
the page was modified, any C bit writeback would have been flushed out
by the tlbie that we did when changing the HPTE to read-only.
Otherwise we need to do a TLB invalidation even if the C bit is 0, and
then check the C bit.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
The dirty map that we construct for the KVM_GET_DIRTY_LOG ioctl has
one bit per system page (4K/64K). Currently, we only set one bit in
the map for each HPT entry with the Change bit set, even if the HPT is
for a large page (e.g., 16MB). Userspace then considers only the
first system page dirty, though in fact the guest may have modified
anywhere in the large page.
To fix this, we make kvm_test_clear_dirty() return the actual number
of pages that are dirty (and rename it to kvm_test_clear_dirty_npages()
to emphasize that that's what it returns). In kvmppc_hv_get_dirty_log()
we then set that many bits in the dirty map.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Currently, when a huge page is faulted in for a guest, we select the
rmap chain to insert the HPTE into based on the guest physical address
that the guest tried to access. Since there is an rmap chain for each
system page, there are many rmap chains for the area covered by a huge
page (e.g. 256 for 16MB pages when PAGE_SIZE = 64kB), and the huge-page
HPTE could end up in any one of them.
For consistency, and to make the huge-page HPTEs easier to find, we now
put huge-page HPTEs in the rmap chain corresponding to the base address
of the huge page.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
The global_invalidates() function contains a check that is intended
to tell whether we are currently executing in the context of a hypercall
issued by the guest. The reason is that the optimization of using a
local TLB invalidate instruction is only valid in that context. The
check was testing local_paca->kvm_hstate.kvm_vcore, which gets set
when entering the guest but no longer gets cleared when exiting the
guest. To fix this, we use the kvm_vcpu field instead, which does
get cleared when exiting the guest, by the kvmppc_release_hwthread()
calls inside kvmppc_run_core().
The effect of having the check wrong was that when kvmppc_do_h_remove()
got called from htab_write() on the destination machine during a
migration, it cleared the current cpu's bit in kvm->arch.need_tlb_flush.
This meant that when the guest started running in the destination VM,
it may miss out on doing a complete TLB flush, and therefore may end
up using stale TLB entries from a previous guest that used the same
LPID value.
This should make migration more reliable.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
We worked around some nasty KVM magic page hcall breakages:
1) NX bit not honored, so ignore NX when we detect it
2) LE guests swizzle hypercall instruction
Without these fixes in place, there's no way it would make sense to expose kvm
hypercalls to a guest. Chances are immensely high it would trip over and break.
So add a new CAP that gives user space a hint that we have workarounds for the
bugs above in place. It can use those as hint to disable PV hypercalls when
the guest CPU is anything POWER7 or higher and the host does not have fixes
in place.
Signed-off-by: Alexander Graf <agraf@suse.de>
When we reset the in-kernel MPIC controller, we forget to reset some hidden
state such as destmask and output. This state is usually set when the guest
writes to the IDR register for a specific IRQ line.
To make sure we stay in sync and don't forget hidden state, treat reset of
the IDR register as a simple write of the IDR register. That automatically
updates all the hidden state as well.
Reported-by: Paul Janzen <pcj@pauljanzen.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
There are LE Linux guests out there that don't handle hypercalls correctly.
Instead of interpreting the instruction stream from device tree as big endian
they assume it's a little endian instruction stream and fail.
When we see an illegal instruction from such a byte reversed instruction stream,
bail out graciously and just declare every hcall as error.
Signed-off-by: Alexander Graf <agraf@suse.de>
Use make_dsisr instead of open coding it. This also have
the added benefit of handling alignment interrupt on additional
instructions.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Although it's optional, IBM POWER cpus always had DAR value set on
alignment interrupt. So don't try to compute these values.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Old guests try to use the magic page, but map their trampoline code inside
of an NX region.
Since we can't fix those old kernels, try to detect whether the guest is sane
or not. If not, just disable NX functionality in KVM so that old guests at
least work at all. For newer guests, add a bit that we can set to keep NX
functionality available.
Signed-off-by: Alexander Graf <agraf@suse.de>
On recent IBM Power CPUs, while the hashed page table is looked up using
the page size from the segmentation hardware (i.e. the SLB), it is
possible to have the HPT entry indicate a larger page size. Thus for
example it is possible to put a 16MB page in a 64kB segment, but since
the hash lookup is done using a 64kB page size, it may be necessary to
put multiple entries in the HPT for a single 16MB page. This
capability is called mixed page-size segment (MPSS). With MPSS,
there are two relevant page sizes: the base page size, which is the
size used in searching the HPT, and the actual page size, which is the
size indicated in the HPT entry. [ Note that the actual page size is
always >= base page size ].
We use "ibm,segment-page-sizes" device tree node to advertise
the MPSS support to PAPR guest. The penc encoding indicates whether
we support a specific combination of base page size and actual
page size in the same segment. We also use the penc value in the
LP encoding of HPTE entry.
This patch exposes MPSS support to KVM guest by advertising the
feature via "ibm,segment-page-sizes". It also adds the necessary changes
to decode the base page size and the actual page size correctly from the
HPTE entry.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Today when KVM tries to reserve memory for the hash page table it
allocates from the normal page allocator first. If that fails it
falls back to CMA's reserved region. One of the side effects of
this is that we could end up exhausting the page allocator and
get linux into OOM conditions while we still have plenty of space
available in CMA.
This patch addresses this issue by first trying hash page table
allocation from CMA's reserved region before falling back to the normal
page allocator. So if we run out of memory, we really are out of memory.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
POWER8 introduces transactional memory which brings along a number of new
registers and MSR bits.
Implementing all of those is a pretty big headache, so for now let's at least
emulate enough to make Linux's context switching code happy.
Signed-off-by: Alexander Graf <agraf@suse.de>
POWER8 introduces a new facility called the "Event Based Branch" facility.
It contains of a few registers that indicate where a guest should branch to
when a defined event occurs and it's in PR mode.
We don't want to really enable EBB as it will create a big mess with !PR guest
mode while hardware is in PR and we don't really emulate the PMU anyway.
So instead, let's just leave it at emulation of all its registers.
Signed-off-by: Alexander Graf <agraf@suse.de>
POWER8 implements a new register called TAR. This register has to be
enabled in FSCR and then from KVM's point of view is mere storage.
This patch enables the guest to use TAR.
Signed-off-by: Alexander Graf <agraf@suse.de>
POWER8 introduced a new interrupt type called "Facility unavailable interrupt"
which contains its status message in a new register called FSCR.
Handle these exits and try to emulate instructions for unhandled facilities.
Follow-on patches enable KVM to expose specific facilities into the guest.
Signed-off-by: Alexander Graf <agraf@suse.de>
In parallel to the Processor ID Register (PIR) threaded POWER8 also adds a
Thread ID Register (TIR). Since PR KVM doesn't emulate more than one thread
per core, we can just always expose 0 here.
Signed-off-by: Alexander Graf <agraf@suse.de>
When we expose a POWER8 CPU into the guest, it will start accessing PMU SPRs
that we don't emulate. Just ignore accesses to them.
Signed-off-by: Alexander Graf <agraf@suse.de>
With the previous patches applied, we can now successfully use PR KVM on
little endian hosts which means we can now allow users to select it.
However, HV KVM still needs some work, so let's keep the kconfig conflict
on that one.
Signed-off-by: Alexander Graf <agraf@suse.de>
When the host CPU we're running on doesn't support dcbz32 itself, but the
guest wants to have dcbz only clear 32 bytes of data, we loop through every
executable mapped page to search for dcbz instructions and patch them with
a special privileged instruction that we emulate as dcbz32.
The only guests that want to see dcbz act as 32byte are book3s_32 guests, so
we don't have to worry about little endian instruction ordering. So let's
just always search for big endian dcbz instructions, also when we're on a
little endian host.
Signed-off-by: Alexander Graf <agraf@suse.de>
The shared (magic) page is a data structure that contains often used
supervisor privileged SPRs accessible via memory to the user to reduce
the number of exits we have to take to read/write them.
When we actually share this structure with the guest we have to maintain
it in guest endianness, because some of the patch tricks only work with
native endian load/store operations.
Since we only share the structure with either host or guest in little
endian on book3s_64 pr mode, we don't have to worry about booke or book3s hv.
For booke, the shared struct stays big endian. For book3s_64 hv we maintain
the struct in host native endian, since it never gets shared with the guest.
For book3s_64 pr we introduce a variable that tells us which endianness the
shared struct is in and route every access to it through helper inline
functions that evaluate this variable.
Signed-off-by: Alexander Graf <agraf@suse.de>
We expose a blob of hypercall instructions to user space that it gives to
the guest via device tree again. That blob should contain a stream of
instructions necessary to do a hypercall in big endian, as it just gets
passed into the guest and old guests use them straight away.
Signed-off-by: Alexander Graf <agraf@suse.de>
When the guest does an RTAS hypercall it keeps all RTAS variables inside a
big endian data structure.
To make sure we don't have to bother about endianness inside the actual RTAS
handlers, let's just convert the whole structure to host endian before we
call our RTAS handlers and back to big endian when we return to the guest.
Signed-off-by: Alexander Graf <agraf@suse.de>
The HTAB on PPC is always in big endian. When we access it via hypercalls
on behalf of the guest and we're running on a little endian host, we need
to make sure we swap the bits accordingly.
Signed-off-by: Alexander Graf <agraf@suse.de>
The default MSR when user space does not define anything should be identical
on little and big endian hosts, so remove MSR_LE from it.
Signed-off-by: Alexander Graf <agraf@suse.de>
The "shadow SLB" in the PACA is shared with the hypervisor, so it has to
be big endian. We access the shadow SLB during world switch, so let's make
sure we access it in big endian even when we're on a little endian host.
Signed-off-by: Alexander Graf <agraf@suse.de>
The HTAB is always big endian. We access the guest's HTAB using
copy_from/to_user, but don't yet take care of the fact that we might
be running on an LE host.
Wrap all accesses to the guest HTAB with big endian accessors.
Signed-off-by: Alexander Graf <agraf@suse.de>
The HTAB is always big endian. We access the guest's HTAB using
copy_from/to_user, but don't yet take care of the fact that we might
be running on an LE host.
Wrap all accesses to the guest HTAB with big endian accessors.
Signed-off-by: Alexander Graf <agraf@suse.de>
Commit 9308ab8e2d made C/R HTAB updates go byte-wise into the target HTAB.
However, it didn't update the guest's copy of the HTAB, but instead the
host local copy of it.
Write to the guest's HTAB instead.
Signed-off-by: Alexander Graf <agraf@suse.de>
CC: Paul Mackerras <paulus@samba.org>
Acked-by: Paul Mackerras <paulus@samba.org>
This patch make sure we inherit the LE bit correctly in different case
so that we can run Little Endian distro in PR mode
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
The dcbtls instruction is able to lock data inside the L1 cache.
We don't want to give the guest actual access to hardware cache locks,
as that could influence other VMs on the same system. But we can tell
the guest that its locking attempt failed.
By implementing the instruction we at least don't give the guest a
program exception which it definitely does not expect.
Signed-off-by: Alexander Graf <agraf@suse.de>
The L1 instruction cache control register contains bits that indicate
that we're still handling a request. Mask those out when we set the SPR
so that a read doesn't assume we're still doing something.
Signed-off-by: Alexander Graf <agraf@suse.de>
Since commit "efcac65 powerpc: Per process DSCR + some fixes (try#4)"
it is no longer possible to set the DSCR on a per-CPU basis.
The old behaviour was to minipulate the DSCR SPR directly but this is no
longer sufficient: the value is quickly overwritten by context switching.
This patch stores the per-CPU DSCR value in a kernel variable rather than
directly in the SPR and it is used whenever a process has not set the DSCR
itself. The sysfs interface (/sys/devices/system/cpu/cpuN/dscr) is unchanged.
Writes to the old global default (/sys/devices/system/cpu/dscr_default)
now set all of the per-CPU values and reads return the last written value.
The new per-CPU default is added to the paca_struct and is used everywhere
outside of sysfs.c instead of the old global default.
Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To support split core on POWER8 we need to modify various parts of the
KVM code to use threads_per_subcore instead of threads_per_core. On
systems that do not support split core threads_per_subcore ==
threads_per_core and these changes are a nop.
We use threads_per_subcore as the value reported by KVM_CAP_PPC_SMT.
This communicates to userspace that guests can only be created with
a value of threads_per_core that is less than or equal to the current
threads_per_subcore. This ensures that guests can only be created with a
thread configuration that we are able to run given the current split
core mode.
Although threads_per_subcore can change during the life of the system,
the commit that enables that will ensure that threads_per_subcore does
not change during the life of a KVM VM.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Acked-by: Alexander Graf <agraf@suse.de>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
As part of the support for split core on POWER8, we want to be able to
block splitting of the core while KVM VMs are active.
The logic to do that would be exactly the same as the code we currently
have for inhibiting onlining of secondaries.
Instead of adding an identical mechanism to block split core, rework the
secondary inhibit code to be a "HV KVM is active" check. We can then use
that in both the cpu hotplug code and the upcoming split core code.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Michael Neuling <mikey@neuling.org>
Acked-by: Alexander Graf <agraf@suse.de>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This request includes a few bug fixes that really shouldn't wait for the next
release.
It fixes KVM on 32bit PowerPC when built as module. It also fixes the PV KVM
acceleration when NX gets honored by the host. Furthermore we fix transactional
memory support and numa support on HV KVM.
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Merge tag 'signed-for-3.15' of git://github.com/agraf/linux-2.6 into kvm-master
Patch queue for 3.15 - 2014-05-12
This request includes a few bug fixes that really shouldn't wait for the next
release.
It fixes KVM on 32bit PowerPC when built as module. It also fixes the PV KVM
acceleration when NX gets honored by the host. Furthermore we fix transactional
memory support and numa support on HV KVM.
This series adds support for building the powerpc 64-bit
LE kernel using the new ABI v2. We already supported
running ABI v2 userspace programs but this adds support
for building the kernel itself using the new ABI.
The book3s_32 target can get built as module which means we don't see the
config define for it in code. Instead, check on the bool define
CONFIG_KVM_BOOK3S_32_HANDLER whenever we want to know whether we're building
for a book3s_32 host.
This fixes running book3s_32 kvm as a module for me.
Signed-off-by: Alexander Graf <agraf@suse.de>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Testing by Michael Neuling revealed that commit e4e3812150 ("KVM:
PPC: Book3S HV: Add transactional memory support") is missing the code
that saves away the checkpointed state of the guest when switching to
the host. This adds that code, which was in earlier versions of the
patch but went missing somehow.
Reported-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Numa fault is a method which help to achieve auto numa balancing.
When such a page fault takes place, the page fault handler will check
whether the page is placed correctly. If not, migration should be
involved to cut down the distance between the cpu and pages.
A pte with _PAGE_NUMA help to implement numa fault. It means not to
allow the MMU to access the page directly. So a page fault is triggered
and numa fault handler gets the opportunity to run checker.
As for the access of MMU, we need special handling for the powernv's guest.
When we mark a pte with _PAGE_NUMA, we already call mmu_notifier to
invalidate it in guest's htab, but when we tried to re-insert them,
we firstly try to map it in real-mode. Only after this fails, we fallback
to virt mode, and most of important, we run numa fault handler in virt
mode. This patch guards the way of real-mode to ensure that if a pte is
marked with _PAGE_NUMA, it will NOT be mapped in real mode, instead, it will
be mapped in virt mode and have the opportunity to be checked with placement.
Signed-off-by: Liu Ping Fan <pingfank@linux.vnet.ibm.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
When the guest cedes the vcpu or the vcpu has no guest to
run it naps. Clear the runlatch bit of the vcpu before
napping to indicate an idle cpu.
Signed-off-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Acked-by: Paul Mackerras <paulus@samba.org>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
The secondary threads in the core are kept offline before launching guests
in kvm on powerpc: "371fefd6f2dc4666:KVM: PPC: Allow book3s_hv guests to use
SMT processor modes."
Hence their runlatch bits are cleared. When the secondary threads are called
in to start a guest, their runlatch bits need to be set to indicate that they
are busy. The primary thread has its runlatch bit set though, but there is no
harm in setting this bit once again. Hence set the runlatch bit for all
threads before they start guest.
Signed-off-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Acked-by: Paul Mackerras <paulus@samba.org>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
There are a few places we have to use dot symbols with the
current ABI - the syscall table and the kvm hcall table.
Wrap both of these with a new macro called DOTSYM so it will
be easy to transition away from dot symbols in a future ABI.
Signed-off-by: Anton Blanchard <anton@samba.org>
binutils is smart enough to know that a branch to a function
descriptor is actually a branch to the functions text address.
Alan tells me that binutils has been doing this for 9 years.
Signed-off-by: Anton Blanchard <anton@samba.org>
Pull kvm updates from Paolo Bonzini:
"PPC and ARM do not have much going on this time. Most of the cool
stuff, instead, is in s390 and (after a few releases) x86.
ARM has some caching fixes and PPC has transactional memory support in
guests. MIPS has some fixes, with more probably coming in 3.16 as
QEMU will soon get support for MIPS KVM.
For x86 there are optimizations for debug registers, which trigger on
some Windows games, and other important fixes for Windows guests. We
now expose to the guest Broadwell instruction set extensions and also
Intel MPX. There's also a fix/workaround for OS X guests, nested
virtualization features (preemption timer), and a couple kvmclock
refinements.
For s390, the main news is asynchronous page faults, together with
improvements to IRQs (floating irqs and adapter irqs) that speed up
virtio devices"
* tag 'kvm-3.15-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (96 commits)
KVM: PPC: Book3S HV: Save/restore host PMU registers that are new in POWER8
KVM: PPC: Book3S HV: Fix decrementer timeouts with non-zero TB offset
KVM: PPC: Book3S HV: Don't use kvm_memslots() in real mode
KVM: PPC: Book3S HV: Return ENODEV error rather than EIO
KVM: PPC: Book3S: Trim top 4 bits of physical address in RTAS code
KVM: PPC: Book3S HV: Add get/set_one_reg for new TM state
KVM: PPC: Book3S HV: Add transactional memory support
KVM: Specify byte order for KVM_EXIT_MMIO
KVM: vmx: fix MPX detection
KVM: PPC: Book3S HV: Fix KVM hang with CONFIG_KVM_XICS=n
KVM: PPC: Book3S: Introduce hypervisor call H_GET_TCE
KVM: PPC: Book3S HV: Fix incorrect userspace exit on ioeventfd write
KVM: s390: clear local interrupts at cpu initial reset
KVM: s390: Fix possible memory leak in SIGP functions
KVM: s390: fix calculation of idle_mask array size
KVM: s390: randomize sca address
KVM: ioapic: reinject pending interrupts on KVM_SET_IRQCHIP
KVM: Bump KVM_MAX_IRQ_ROUTES for s390
KVM: s390: irq routing for adapter interrupts.
KVM: s390: adapter interrupt sources
...
Pull main powerpc updates from Ben Herrenschmidt:
"This time around, the powerpc merges are going to be a little bit more
complicated than usual.
This is the main pull request with most of the work for this merge
window. I will describe it a bit more further down.
There is some additional cpuidle driver work, however I haven't
included it in this tree as it depends on some work in tip/timer-core
which Thomas accidentally forgot to put in a topic branch. Since I
didn't want to carry all of that tip timer stuff in powerpc -next, I
setup a separate branch on top of Thomas tree with just that cpuidle
driver in it, and Stephen has been carrying that in next separately
for a while now. I'll send a separate pull request for it.
Additionally, two new pieces in this tree add users for a sysfs API
that Tejun and Greg have been deprecating in drivers-core-next.
Thankfully Greg reverted the patch that removes the old API so this
merge can happen cleanly, but once merged, I will send a patch
adjusting our new code to the new API so that Greg can send you the
removal patch.
Now as for the content of this branch, we have a lot of perf work for
power8 new counters including support for our new "nest" counters
(also called 24x7) under pHyp (not natively yet).
We have new functionality when running under the OPAL firmware
(non-virtualized or KVM host), such as access to the firmware error
logs and service processor dumps, system parameters and sensors, along
with a hwmon driver for the latter.
There's also a bunch of bug fixes accross the board, some LE fixes,
and a nice set of selftests for validating our various types of copy
loops.
On the Freescale side, we see mostly new chip/board revisions, some
clock updates, better support for machine checks and debug exceptions,
etc..."
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (70 commits)
powerpc/book3s: Fix CFAR clobbering issue in machine check handler.
powerpc/compat: 32-bit little endian machine name is ppcle, not ppc
powerpc/le: Big endian arguments for ppc_rtas()
powerpc: Use default set of netfilter modules (CONFIG_NETFILTER_ADVANCED=n)
powerpc/defconfigs: Enable THP in pseries defconfig
powerpc/mm: Make sure a local_irq_disable prevent a parallel THP split
powerpc: Rate-limit users spamming kernel log buffer
powerpc/perf: Fix handling of L3 events with bank == 1
powerpc/perf/hv_{gpci, 24x7}: Add documentation of device attributes
powerpc/perf: Add kconfig option for hypervisor provided counters
powerpc/perf: Add support for the hv 24x7 interface
powerpc/perf: Add support for the hv gpci (get performance counter info) interface
powerpc/perf: Add macros for defining event fields & formats
powerpc/perf: Add a shared interface to get gpci version and capabilities
powerpc/perf: Add 24x7 interface headers
powerpc/perf: Add hv_gpci interface header
powerpc: Add hvcalls for 24x7 and gpci (Get Performance Counter Info)
sysfs: create bin_attributes under the requested group
powerpc/perf: Enable BHRB access for EBB events
powerpc/perf: Add BHRB constraint and IFM MMCRA handling for EBB
...
Currently we save the host PMU configuration, counter values, etc.,
when entering a guest, and restore it on return from the guest.
(We have to do this because the guest has control of the PMU while
it is executing.) However, we missed saving/restoring the SIAR and
SDAR registers, as well as the registers which are new on POWER8,
namely SIER and MMCR2.
This adds code to save the values of these registers when entering
the guest and restore them on exit. This also works around the bug
in POWER8 where setting PMAE with a counter already negative doesn't
generate an interrupt.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Acked-by: Scott Wood <scottwood@freescale.com>
Commit c7699822bc21 ("KVM: PPC: Book3S HV: Make physical thread 0 do
the MMU switching") reordered the guest entry/exit code so that most
of the guest register save/restore code happened in guest MMU context.
A side effect of that is that the timebase still contains the guest
timebase value at the point where we compute and use vcpu->arch.dec_expires,
and therefore that is now a guest timebase value rather than a host
timebase value. That in turn means that the timeouts computed in
kvmppc_set_timer() are wrong if the timebase offset for the guest is
non-zero. The consequence of that is things such as "sleep 1" in a
guest after migration may sleep for much longer than they should.
This fixes the problem by converting between guest and host timebase
values as necessary, by adding or subtracting the timebase offset.
This also fixes an incorrect comment.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Acked-by: Scott Wood <scottwood@freescale.com>
With HV KVM, some high-frequency hypercalls such as H_ENTER are handled
in real mode, and need to access the memslots array for the guest.
Accessing the memslots array is safe, because we hold the SRCU read
lock for the whole time that a guest vcpu is running. However, the
checks that kvm_memslots() does when lockdep is enabled are potentially
unsafe in real mode, when only the linear mapping is available.
Furthermore, kvm_memslots() can be called from a secondary CPU thread,
which is an offline CPU from the point of view of the host kernel,
and is not running the task which holds the SRCU read lock.
To avoid false positives in the checks in kvm_memslots(), and to avoid
possible side effects from doing the checks in real mode, this replaces
kvm_memslots() with kvm_memslots_raw() in all the places that execute
in real mode. kvm_memslots_raw() is a new function that is like
kvm_memslots() but uses rcu_dereference_raw_notrace() instead of
kvm_dereference_check().
Signed-off-by: Paul Mackerras <paulus@samba.org>
Acked-by: Scott Wood <scottwood@freescale.com>
If an attempt is made to load the kvm-hv module on a machine which
doesn't have hypervisor mode available, return an ENODEV error,
which is the conventional thing to return to indicate that this
module is not applicable to the hardware of the current machine,
rather than EIO, which causes a warning to be printed.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Acked-by: Scott Wood <scottwood@freescale.com>
The in-kernel emulation of RTAS functions needs to read the argument
buffer from guest memory in order to find out what function is being
requested. The guest supplies the guest physical address of the buffer,
and on a real system the code that reads that buffer would run in guest
real mode. In guest real mode, the processor ignores the top 4 bits
of the address specified in load and store instructions. In order to
emulate that behaviour correctly, we need to mask off those bits
before calling kvm_read_guest() or kvm_write_guest(). This adds that
masking.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Acked-by: Scott Wood <scottwood@freescale.com>
This adds code to get/set_one_reg to read and write the new transactional
memory (TM) state.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Acked-by: Scott Wood <scottwood@freescale.com>
This adds saving of the transactional memory (TM) checkpointed state
on guest entry and exit. We only do this if we see that the guest has
an active transaction.
It also adds emulation of the TM state changes when delivering IRQs
into the guest. According to the architecture, if we are
transactional when an IRQ occurs, the TM state is changed to
suspended, otherwise it's left unchanged.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Acked-by: Scott Wood <scottwood@freescale.com>
I noticed KVM is broken when KVM in-kernel XICS emulation
(CONFIG_KVM_XICS) is disabled.
The problem was introduced in 48eaef05 (KVM: PPC: Book3S HV: use
xics_wake_cpu only when defined). It used CONFIG_KVM_XICS to wrap
xics_wake_cpu, where CONFIG_PPC_ICP_NATIVE should have been
used.
Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: stable@vger.kernel.org
Signed-off-by: Paul Mackerras <paulus@samba.org>
Acked-by: Scott Wood <scottwood@freescale.com>
This introduces the H_GET_TCE hypervisor call, which is basically the
reverse of H_PUT_TCE, as defined in the Power Architecture Platform
Requirements (PAPR).
The hcall H_GET_TCE is required by the kdump kernel, which uses it to
retrieve TCEs set up by the previous (panicked) kernel.
Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Paul Mackerras <paulus@samba.org>
When the guest does an MMIO write which is handled successfully by an
ioeventfd, ioeventfd_write() returns 0 (success) and
kvmppc_handle_store() returns EMULATE_DONE. Then
kvmppc_emulate_mmio() converts EMULATE_DONE to RESUME_GUEST_NV and
this causes an exit from the loop in kvmppc_vcpu_run_hv(), causing an
exit back to userspace with a bogus exit reason code, typically
causing userspace (e.g. qemu) to crash with a message about an unknown
exit code.
This adds handling of RESUME_GUEST_NV in kvmppc_vcpu_run_hv() in order
to fix that. For generality, we define a helper to check for either
of the return-to-guest codes we use, RESUME_GUEST and RESUME_GUEST_NV,
to make it easy to check for either and provide one place to update if
any other return-to-guest code gets defined in future.
Since it only affects Book3S HV for now, the helper is added to
the kvm_book3s.h header file.
We use the helper in two places in kvmppc_run_core() as well for
future-proofing, though we don't see RESUME_GUEST_NV in either place
at present.
[paulus@samba.org - combined 4 patches into one, rewrote description]
Suggested-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
While bolted handlers (including e6500) do not need to deal with a TLB
miss recursively causing another TLB miss, nested TLB misses can still
happen with crit/mc/debug exceptions -- so we still need to honor
SPRG_TLB_EXFRAME.
We don't need to spend time modifying it in the TLB miss fastpath,
though -- the special level exception will handle that.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Cc: Mihai Caraman <mihai.caraman@freescale.com>
Cc: kvm-ppc@vger.kernel.org
Previously SPRG3 was marked for use by both VDSO and critical
interrupts (though critical interrupts were not fully implemented).
In commit 8b64a9dfb0 ("powerpc/booke64:
Use SPRG0/3 scratch for bolted TLB miss & crit int"), Mihai Caraman
made an attempt to resolve this conflict by restoring the VDSO value
early in the critical interrupt, but this has some issues:
- It's incompatible with EXCEPTION_COMMON which restores r13 from the
by-then-overwritten scratch (this cost me some debugging time).
- It forces critical exceptions to be a special case handled
differently from even machine check and debug level exceptions.
- It didn't occur to me that it was possible to make this work at all
(by doing a final "ld r13, PACA_EXCRIT+EX_R13(r13)") until after
I made (most of) this patch. :-)
It might be worth investigating using a load rather than SPRG on return
from all exceptions (except TLB misses where the scratch never leaves
the SPRG) -- it could save a few cycles. Until then, let's stick with
SPRG for all exceptions.
Since we cannot use SPRG4-7 for scratch without corrupting the state of
a KVM guest, move VDSO to SPRG7 on book3e. Since neither SPRG4-7 nor
critical interrupts exist on book3s, SPRG3 is still used for VDSO
there.
Signed-off-by: Scott Wood <scottwood@freescale.com>
Cc: Mihai Caraman <mihai.caraman@freescale.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: kvm-ppc@vger.kernel.org
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull another kvm fix from Paolo Bonzini:
"A fix for a PowerPC bug that was introduced during the 3.14 merge
window"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: PPC: Book3S HV: Fix register usage when loading/saving VRSAVE
KVM: PPC: Book3S HV: Remove bogus duplicate code
Commit 595e4f7e69 ("KVM: PPC: Book3S HV: Use load/store_fp_state
functions in HV guest entry/exit") changed the register usage in
kvmppc_save_fp() and kvmppc_load_fp() but omitted changing the
instructions that load and save VRSAVE. The result is that the
VRSAVE value was loaded from a constant address, and saved to a
location past the end of the vcpu struct, causing host kernel
memory corruption and various kinds of host kernel crashes.
This fixes the problem by using register r31, which contains the
vcpu pointer, instead of r3 and r4.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Commit 7b490411c3 ("KVM: PPC: Book3S HV: Add new state for
transactional memory") incorrectly added some duplicate code to the
guest exit path because I didn't manage to clean up after a rebase
correctly. This removes the extraneous material. The presence of
this extraneous code causes host crashes whenever a guest is run.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
two s390 guest features that need some handling in the host,
and all the PPC changes. The PPC changes include support for
little-endian guests and enablement for new POWER8 features.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull more KVM updates from Paolo Bonzini:
"Second batch of KVM updates. Some minor x86 fixes, two s390 guest
features that need some handling in the host, and all the PPC changes.
The PPC changes include support for little-endian guests and
enablement for new POWER8 features"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (45 commits)
x86, kvm: correctly access the KVM_CPUID_FEATURES leaf at 0x40000101
x86, kvm: cache the base of the KVM cpuid leaves
kvm: x86: move KVM_CAP_HYPERV_TIME outside #ifdef
KVM: PPC: Book3S PR: Cope with doorbell interrupts
KVM: PPC: Book3S HV: Add software abort codes for transactional memory
KVM: PPC: Book3S HV: Add new state for transactional memory
powerpc/Kconfig: Make TM select VSX and VMX
KVM: PPC: Book3S HV: Basic little-endian guest support
KVM: PPC: Book3S HV: Add support for DABRX register on POWER7
KVM: PPC: Book3S HV: Prepare for host using hypervisor doorbells
KVM: PPC: Book3S HV: Handle new LPCR bits on POWER8
KVM: PPC: Book3S HV: Handle guest using doorbells for IPIs
KVM: PPC: Book3S HV: Consolidate code that checks reason for wake from nap
KVM: PPC: Book3S HV: Implement architecture compatibility modes for POWER8
KVM: PPC: Book3S HV: Add handler for HV facility unavailable
KVM: PPC: Book3S HV: Flush the correct number of TLB sets on POWER8
KVM: PPC: Book3S HV: Context-switch new POWER8 SPRs
KVM: PPC: Book3S HV: Align physical and virtual CPU thread numbers
KVM: PPC: Book3S HV: Don't set DABR on POWER8
kvm/ppc: IRQ disabling cleanup
...
Pull powerpc updates from Ben Herrenschmidt:
"So here's my next branch for powerpc. A bit late as I was on vacation
last week. It's mostly the same stuff that was in next already, I
just added two patches today which are the wiring up of lockref for
powerpc, which for some reason fell through the cracks last time and
is trivial.
The highlights are, in addition to a bunch of bug fixes:
- Reworked Machine Check handling on kernels running without a
hypervisor (or acting as a hypervisor). Provides hooks to handle
some errors in real mode such as TLB errors, handle SLB errors,
etc...
- Support for retrieving memory error information from the service
processor on IBM servers running without a hypervisor and routing
them to the memory poison infrastructure.
- _PAGE_NUMA support on server processors
- 32-bit BookE relocatable kernel support
- FSL e6500 hardware tablewalk support
- A bunch of new/revived board support
- FSL e6500 deeper idle states and altivec powerdown support
You'll notice a generic mm change here, it has been acked by the
relevant authorities and is a pre-req for our _PAGE_NUMA support"
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (121 commits)
powerpc: Implement arch_spin_is_locked() using arch_spin_value_unlocked()
powerpc: Add support for the optimised lockref implementation
powerpc/powernv: Call OPAL sync before kexec'ing
powerpc/eeh: Escalate error on non-existing PE
powerpc/eeh: Handle multiple EEH errors
powerpc: Fix transactional FP/VMX/VSX unavailable handlers
powerpc: Don't corrupt transactional state when using FP/VMX in kernel
powerpc: Reclaim two unused thread_info flag bits
powerpc: Fix races with irq_work
Move precessing of MCE queued event out from syscall exit path.
pseries/cpuidle: Remove redundant call to ppc64_runlatch_off() in cpu idle routines
powerpc: Make add_system_ram_resources() __init
powerpc: add SATA_MV to ppc64_defconfig
powerpc/powernv: Increase candidate fw image size
powerpc: Add debug checks to catch invalid cpu-to-node mappings
powerpc: Fix the setup of CPU-to-Node mappings during CPU online
powerpc/iommu: Don't detach device without IOMMU group
powerpc/eeh: Hotplug improvement
powerpc/eeh: Call opal_pci_reinit() on powernv for restoring config space
powerpc/eeh: Add restore_config operation
...
Add new state for transactional memory (TM) to kvm_vcpu_arch. Also add
asm-offset bits that are going to be required.
This also moves the existing TFHAR, TFIAR and TEXASR SPRs into a
CONFIG_PPC_TRANSACTIONAL_MEM section. This requires some code changes to
ensure we still compile with CONFIG_PPC_TRANSACTIONAL_MEM=N. Much of the added
the added #ifdefs are removed in a later patch when the bulk of the TM code is
added.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
[agraf: fix merge conflict]
Signed-off-by: Alexander Graf <agraf@suse.de>
We create a guest MSR from scratch when delivering exceptions in
a few places. Instead of extracting LPCR[ILE] and inserting it
into MSR_LE each time, we simply create a new variable intr_msr which
contains the entire MSR to use. For a little-endian guest, userspace
needs to set the ILE (interrupt little-endian) bit in the LPCR for
each vcpu (or at least one vcpu in each virtual core).
[paulus@samba.org - removed H_SET_MODE implementation from original
version of the patch, and made kvmppc_set_lpcr update vcpu->arch.intr_msr.]
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
The DABRX (DABR extension) register on POWER7 processors provides finer
control over which accesses cause a data breakpoint interrupt. It
contains 3 bits which indicate whether to enable accesses in user,
kernel and hypervisor modes respectively to cause data breakpoint
interrupts, plus one bit that enables both real mode and virtual mode
accesses to cause interrupts. Currently, KVM sets DABRX to allow
both kernel and user accesses to cause interrupts while in the guest.
This adds support for the guest to specify other values for DABRX.
PAPR defines a H_SET_XDABR hcall to allow the guest to set both DABR
and DABRX with one call. This adds a real-mode implementation of
H_SET_XDABR, which shares most of its code with the existing H_SET_DABR
implementation. To support this, we add a per-vcpu field to store the
DABRX value plus code to get and set it via the ONE_REG interface.
For Linux guests to use this new hcall, userspace needs to add
"hcall-xdabr" to the set of strings in the /chosen/hypertas-functions
property in the device tree. If userspace does this and then migrates
the guest to a host where the kernel doesn't include this patch, then
userspace will need to implement H_SET_XDABR by writing the specified
DABR value to the DABR using the ONE_REG interface. In that case, the
old kernel will set DABRX to DABRX_USER | DABRX_KERNEL. That should
still work correctly, at least for Linux guests, since Linux guests
cope with getting data breakpoint interrupts in modes that weren't
requested by just ignoring the interrupt, and Linux guests never set
DABRX_BTI.
The other thing this does is to make H_SET_DABR and H_SET_XDABR work
on POWER8, which has the DAWR and DAWRX instead of DABR/X. Guests that
know about POWER8 should use H_SET_MODE rather than H_SET_[X]DABR, but
guests running in POWER7 compatibility mode will still use H_SET_[X]DABR.
For them, this adds the logic to convert DABR/X values into DAWR/X values
on POWER8.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
POWER8 has support for hypervisor doorbell interrupts. Though the
kernel doesn't use them for IPIs on the powernv platform yet, it
probably will in future, so this makes KVM cope gracefully if a
hypervisor doorbell interrupt arrives while in a guest.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
POWER8 has a bit in the LPCR to enable or disable the PURR and SPURR
registers to count when in the guest. Set this bit.
POWER8 has a field in the LPCR called AIL (Alternate Interrupt Location)
which is used to enable relocation-on interrupts. Allow userspace to
set this field.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
* SRR1 wake reason field for system reset interrupt on wakeup from nap
is now a 4-bit field on P8, compared to 3 bits on P7.
* Set PECEDP in LPCR when napping because of H_CEDE so guest doorbells
will wake us up.
* Waking up from nap because of a guest doorbell interrupt is not a
reason to exit the guest.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Currently in book3s_hv_rmhandlers.S we have three places where we
have woken up from nap mode and we check the reason field in SRR1
to see what event woke us up. This consolidates them into a new
function, kvmppc_check_wake_reason. It looks at the wake reason
field in SRR1, and if it indicates that an external interrupt caused
the wakeup, calls kvmppc_read_intr to check what sort of interrupt
it was.
This also consolidates the two places where we synthesize an external
interrupt (0x500 vector) for the guest. Now, if the guest exit code
finds that there was an external interrupt which has been handled
(i.e. it was an IPI indicating that there is now an interrupt pending
for the guest), it jumps to deliver_guest_interrupt, which is in the
last part of the guest entry code, where we synthesize guest external
and decrementer interrupts. That code has been streamlined a little
and now clears LPCR[MER] when appropriate as well as setting it.
The extra clearing of any pending IPI on a secondary, offline CPU
thread before going back to nap mode has been removed. It is no longer
necessary now that we have code to read and acknowledge IPIs in the
guest exit path.
This fixes a minor bug in the H_CEDE real-mode handling - previously,
if we found that other threads were already exiting the guest when we
were about to go to nap mode, we would branch to the cede wakeup path
and end up looking in SRR1 for a wakeup reason. Now we branch to a
point after we have checked the wakeup reason.
This also fixes a minor bug in kvmppc_read_intr - previously it could
return 0xff rather than 1, in the case where we find that a host IPI
is pending after we have cleared the IPI. Now it returns 1.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
This allows us to select architecture 2.05 (POWER6) or 2.06 (POWER7)
compatibility modes on a POWER8 processor. (Note that transactional
memory is disabled for usermode if either or both of the PCR_TM_DIS
and PCR_ARCH_206 bits are set.)
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
At present this should never happen, since the host kernel sets
HFSCR to allow access to all facilities. It's better to be prepared
to handle it cleanly if it does ever happen, though.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
POWER8 has 512 sets in the TLB, compared to 128 for POWER7, so we need
to do more tlbiel instructions when flushing the TLB on POWER8.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
This adds fields to the struct kvm_vcpu_arch to store the new
guest-accessible SPRs on POWER8, adds code to the get/set_one_reg
functions to allow userspace to access this state, and adds code to
the guest entry and exit to context-switch these SPRs between host
and guest.
Note that DPDES (Directed Privileged Doorbell Exception State) is
shared between threads on a core; hence we store it in struct
kvmppc_vcore and have the master thread save and restore it.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
On a threaded processor such as POWER7, we group VCPUs into virtual
cores and arrange that the VCPUs in a virtual core run on the same
physical core. Currently we don't enforce any correspondence between
virtual thread numbers within a virtual core and physical thread
numbers. Physical threads are allocated starting at 0 on a first-come
first-served basis to runnable virtual threads (VCPUs).
POWER8 implements a new "msgsndp" instruction which guest kernels can
use to interrupt other threads in the same core or sub-core. Since
the instruction takes the destination physical thread ID as a parameter,
it becomes necessary to align the physical thread IDs with the virtual
thread IDs, that is, to make sure virtual thread N within a virtual
core always runs on physical thread N.
This means that it's possible that thread 0, which is where we call
__kvmppc_vcore_entry, may end up running some other vcpu than the
one whose task called kvmppc_run_core(), or it may end up running
no vcpu at all, if for example thread 0 of the virtual core is
currently executing in userspace. However, we do need thread 0
to be responsible for switching the MMU -- a previous version of
this patch that had other threads switching the MMU was found to
be responsible for occasional memory corruption and machine check
interrupts in the guest on POWER7 machines.
To accommodate this, we no longer pass the vcpu pointer to
__kvmppc_vcore_entry, but instead let the assembly code load it from
the PACA. Since the assembly code will need to know the kvm pointer
and the thread ID for threads which don't have a vcpu, we move the
thread ID into the PACA and we add a kvm pointer to the virtual core
structure.
In the case where thread 0 has no vcpu to run, it still calls into
kvmppc_hv_entry in order to do the MMU switch, and then naps until
either its vcpu is ready to run in the guest, or some other thread
needs to exit the guest. In the latter case, thread 0 jumps to the
code that switches the MMU back to the host. This control flow means
that now we switch the MMU before loading any guest vcpu state.
Similarly, on guest exit we now save all the guest vcpu state before
switching the MMU back to the host. This has required substantial
code movement, making the diff rather large.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
POWER8 doesn't have the DABR and DABRX registers; instead it has
new DAWR/DAWRX registers, which will be handled in a later patch.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
