Commit Graph

7192 Commits

Author SHA1 Message Date
Gleb Natapov
fe4c7b1914 KVM: reuse (pop|push)_irq from svm.c in vmx.c
The prioritized bit vector manipulation functions are useful in both vmx and
svm.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10 11:48:31 +03:00
Gleb Natapov
61c50edfcd KVM: SVM: Remove duplicate code in svm_do_inject_vector()
svm_do_inject_vector() reimplements pop_irq().

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10 11:48:30 +03:00
Amit Shah
7fe29e0faa KVM: x86: Ignore reads to EVNTSEL MSRs
We ignore writes to the performance counters and performance event
selector registers already. Kaspersky antivirus reads the eventsel
MSR causing it to crash with the current behaviour.

Return 0 as data when the eventsel registers are read to stop the
crash.

Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10 11:48:30 +03:00
Gleb Natapov
f00be0cae4 KVM: MMU: do not free active mmu pages in free_mmu_pages()
free_mmu_pages() should only undo what alloc_mmu_pages() does.
Free mmu pages from the generic VM destruction function, kvm_destroy_vm().

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10 11:48:30 +03:00
Sheng Yang
e56d532f20 KVM: Device assignment framework rework
After discussion with Marcelo, we decided to rework device assignment framework
together. The old problems are kernel logic is unnecessary complex. So Marcelo
suggest to split it into a more elegant way:

1. Split host IRQ assign and guest IRQ assign. And userspace determine the
combination. Also discard msi2intx parameter, userspace can specific
KVM_DEV_IRQ_HOST_MSI | KVM_DEV_IRQ_GUEST_INTX in assigned_irq->flags to
enable MSI to INTx convertion.

2. Split assign IRQ and deassign IRQ. Import two new ioctls:
KVM_ASSIGN_DEV_IRQ and KVM_DEASSIGN_DEV_IRQ.

This patch also fixed the reversed _IOR vs _IOW in definition(by deprecated the
old interface).

[avi: replace homemade bitcount() by hweight_long()]

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10 11:48:29 +03:00
Hannes Eder
386eb6e8b3 KVM: make 'lapic_timer_ops' and 'kpit_ops' static
Fix this sparse warnings:
  arch/x86/kvm/lapic.c:916:22: warning: symbol 'lapic_timer_ops' was not declared. Should it be static?
  arch/x86/kvm/i8254.c:268:22: warning: symbol 'kpit_ops' was not declared. Should it be static?

Signed-off-by: Hannes Eder <hannes@hanneseder.net>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10 11:48:29 +03:00
Gleb Natapov
58c2dde17d KVM: APIC: get rid of deliver_bitmask
Deliver interrupt during destination matching loop.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Acked-by: Xiantao Zhang <xiantao.zhang@intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-06-10 11:48:27 +03:00
Gleb Natapov
e1035715ef KVM: change the way how lowest priority vcpu is calculated
The new way does not require additional loop over vcpus to calculate
the one with lowest priority as one is chosen during delivery bitmap
construction.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-06-10 11:48:27 +03:00
Gleb Natapov
343f94fe4d KVM: consolidate ioapic/ipi interrupt delivery logic
Use kvm_apic_match_dest() in kvm_get_intr_delivery_bitmask() instead
of duplicating the same code. Use kvm_get_intr_delivery_bitmask() in
apic_send_ipi() to figure out ipi destination instead of reimplementing
the logic.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-06-10 11:48:27 +03:00
Gleb Natapov
6da7e3f643 KVM: APIC: kvm_apic_set_irq deliver all kinds of interrupts
Get rid of ioapic_inj_irq() and ioapic_inj_nmi() functions.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-06-10 11:48:26 +03:00
Joerg Roedel
f5a1e9f895 KVM: MMU: remove call to kvm_mmu_pte_write from walk_addr
There is no reason to update the shadow pte here because the guest pte
is only changed to dirty state.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
2009-06-10 11:48:26 +03:00
Marcelo Tosatti
d3c7b77d1a KVM: unify part of generic timer handling
Hide the internals of vcpu awakening / injection from the in-kernel
emulated timers. This makes future changes in this logic easier and
decreases the distance to more generic timer handling.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10 11:48:25 +03:00
Marcelo Tosatti
fd66842370 KVM: PIT: remove usage of count_load_time for channel 0
We can infer elapsed time from hrtimer_expires_remaining.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10 11:48:25 +03:00
Marcelo Tosatti
5a05d54554 KVM: PIT: remove unused scheduled variable
Unused.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10 11:48:25 +03:00
Marcelo Tosatti
a90ede7b17 KVM: x86: paravirt skip pit-through-ioapic boot check
Skip the test which checks if the PIT is properly routed when
using the IOAPIC, aimed at buggy hardware.

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10 11:48:24 +03:00
Matt T. Yourst
2dea4c84bc KVM: x86: silence preempt warning on kvm_write_guest_time
This issue just appeared in kvm-84 when running on 2.6.28.7 (x86-64)
with PREEMPT enabled.

We're getting syslog warnings like this many (but not all) times qemu
tells KVM to run the VCPU:

BUG: using smp_processor_id() in preemptible [00000000] code:
qemu-system-x86/28938
caller is kvm_arch_vcpu_ioctl_run+0x5d1/0xc70 [kvm]
Pid: 28938, comm: qemu-system-x86 2.6.28.7-mtyrel-64bit
Call Trace:
debug_smp_processor_id+0xf7/0x100
kvm_arch_vcpu_ioctl_run+0x5d1/0xc70 [kvm]
? __wake_up+0x4e/0x70
? wake_futex+0x27/0x40
kvm_vcpu_ioctl+0x2e9/0x5a0 [kvm]
enqueue_hrtimer+0x8a/0x110
_spin_unlock_irqrestore+0x27/0x50
vfs_ioctl+0x31/0xa0
do_vfs_ioctl+0x74/0x480
sys_futex+0xb4/0x140
sys_ioctl+0x99/0xa0
system_call_fastpath+0x16/0x1b

As it turns out, the call trace is messed up due to gcc's inlining, but
I isolated the problem anyway: kvm_write_guest_time() is being used in a
non-thread-safe manner on preemptable kernels.

Basically kvm_write_guest_time()'s body needs to be surrounded by
preempt_disable() and preempt_enable(), since the kernel won't let us
query any per-CPU data (indirectly using smp_processor_id()) without
preemption disabled. The attached patch fixes this issue by disabling
preemption inside kvm_write_guest_time().

[marcelo: surround only __get_cpu_var calls since the warning
is harmless]

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10 11:48:24 +03:00
Sheng Yang
d510d6cc65 KVM: Enable MSI-X for KVM assigned device
This patch finally enable MSI-X.

What we need for MSI-X:
1. Intercept one page in MMIO region of device. So that we can get guest desired
MSI-X table and set up the real one. Now this have been done by guest, and
transfer to kernel using ioctl KVM_SET_MSIX_NR and KVM_SET_MSIX_ENTRY.

2. Information for incoming interrupt. Now one device can have more than one
interrupt, and they are all handled by one workqueue structure. So we need to
identify them. The previous patch enable gsi_msg_pending_bitmap get this done.

3. Mapping from host IRQ to guest gsi as well as guest gsi to real MSI/MSI-X
message address/data. We used same entry number for the host and guest here, so
that it's easy to find the correlated guest gsi.

What we lack for now:
1. The PCI spec said nothing can existed with MSI-X table in the same page of
MMIO region, except pending bits. The patch ignore pending bits as the first
step (so they are always 0 - no pending).

2. The PCI spec allowed to change MSI-X table dynamically. That means, the OS
can enable MSI-X, then mask one MSI-X entry, modify it, and unmask it. The patch
didn't support this, and Linux also don't work in this way.

3. The patch didn't implement MSI-X mask all and mask single entry. I would
implement the former in driver/pci/msi.c later. And for single entry, userspace
should have reposibility to handle it.

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10 11:48:23 +03:00
Sheng Yang
bfd349d073 KVM: bit ops for deliver_bitmap
It's also convenient when we extend KVM supported vcpu number in the future.

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10 11:48:22 +03:00
Sheng Yang
110c2faeba KVM: Update intr delivery func to accept unsigned long* bitmap
Would be used with bit ops, and would be easily extended if KVM_MAX_VCPUS is
increased.

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10 11:48:22 +03:00
Avi Kivity
5897297bc2 KVM: VMX: Don't intercept MSR_KERNEL_GS_BASE
Windows 2008 accesses this MSR often on context switch intensive workloads;
since we run in guest context with the guest MSR value loaded (so swapgs can
work correctly), we can simply disable interception of rdmsr/wrmsr for this
MSR.

A complication occurs since in legacy mode, we run with the host MSR value
loaded. In this case we enable interception.  This means we need two MSR
bitmaps, one for legacy mode and one for long mode.

Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10 11:48:21 +03:00
Avi Kivity
3e7c73e9b1 KVM: VMX: Don't use highmem pages for the msr and pio bitmaps
Highmem pages are a pain, and saving three lowmem pages on i386 isn't worth
the extra code.

Signed-off-by: Avi Kivity <avi@redhat.com>
2009-06-10 11:48:21 +03:00
Yinghai Lu
eaa958402e cpumask: alloc zeroed cpumask for static cpumask_var_ts
These are defined as static cpumask_var_t so if MAXSMP is not used,
they are cleared already.  Avoid surprises when MAXSMP is enabled.

Signed-off-by: Yinghai Lu <yinghai.lu@kernel.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2009-06-09 22:30:27 +09:30
Linus Torvalds
ccc0d38ec1 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci-2.6:
  x86/pci: fix mmconfig detection with 32bit near 4g
  PCI: use fixed-up device class when configuring device
2009-06-06 14:33:54 -07:00
Dave Jones
2c701b1028 [CPUFREQ] powernow-k8: check space_id of _PCT registers to be FFH
The powernow-k8 driver checks to see that the Performance Control/Status
Registers are declared as FFH (functional fixed hardware) by the BIOS.
However, this check got broken in the commit:
 0e64a0c982
 [CPUFREQ] checkpatch cleanups for powernow-k8

Fix based on an original patch from Naga Chumbalkar.

Signed-off-by: Naga Chumbalkar <nagananda.chumbalkar@hp.com>
Cc: Mark Langsdorf <mark.langsdorf@amd.com>
Signed-off-by: Dave Jones <davej@redhat.com>
2009-06-05 13:25:25 -04:00
Rusty Russell
2cb7878a3a lguest: fix 'unhandled trap 13' with CONFIG_CC_STACKPROTECTOR
We don't set up the canary; let's disable stack protector on boot.c so
we can get into lguest_init, then set it up.  As a side effect,
switch_to_new_gdt() sets up %fs for us properly too.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-04 11:50:06 -07:00
Yinghai Lu
75e613cdc7 x86/pci: fix mmconfig detection with 32bit near 4g
Pascal reported and bisected a commit:
|	x86/PCI: don't call e820_all_mapped with -1 in the mmconfig case

which broke one system system.

ACPI: Using IOAPIC for interrupt routing
PCI: MCFG configuration 0: base f0000000 segment 0 buses 0 - 255
PCI: MCFG area at f0000000 reserved in ACPI motherboard resources
PCI: Using MMCONFIG for extended config space

it didn't have
PCI: updated MCFG configuration 0: base f0000000 segment 0 buses 0 - 63
anymore, and try to use 0xf000000 - 0xffffffff for mmconfig

For 32bit, mcfg_res->end could be 32bit only (if 64 resources aren't used)
So use end - 1 to pass the value in mcfg->end to avoid overflow.

We don't need to worry about the e820 path, they are always 64 bit.

Reported-by: Pascal Terjan <pterjan@mandriva.com>
Bisected-by: Pascal Terjan <pterjan@mandriva.com>
Tested-by: Pascal Terjan <pterjan@mandriva.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: stable@kernel.org
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2009-06-04 11:31:13 +01:00
Joe Perches
61c8c67e3a acpi-cpufreq: fix printk typo and indentation
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
2009-05-29 21:26:26 -04:00
Mel Gorman
32b154c0b0 x86: ignore VM_LOCKED when determining if hugetlb-backed page tables can be shared or not
Addresses http://bugzilla.kernel.org/show_bug.cgi?id=13302

On x86 and x86-64, it is possible that page tables are shared beween
shared mappings backed by hugetlbfs.  As part of this,
page_table_shareable() checks a pair of vma->vm_flags and they must match
if they are to be shared.  All VMA flags are taken into account, including
VM_LOCKED.

The problem is that VM_LOCKED is cleared on fork().  When a process with a
shared memory segment forks() to exec() a helper, there will be shared
VMAs with different flags.  The impact is that the shared segment is
sometimes considered shareable and other times not, depending on what
process is checking.

What happens is that the segment page tables are being shared but the
count is inaccurate depending on the ordering of events.  As the page
tables are freed with put_page(), bad pmd's are found when some of the
children exit.  The hugepage counters also get corrupted and the Total and
Free count will no longer match even when all the hugepage-backed regions
are freed.  This requires a reboot of the machine to "fix".

This patch addresses the problem by comparing all flags except VM_LOCKED
when deciding if pagetables should be shared or not for hugetlbfs-backed
mapping.

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: <stable@kernel.org>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: <starlight@binnacle.cx>
Cc: Eric B Munson <ebmunson@us.ibm.com>
Cc: Adam Litke <agl@us.ibm.com>
Cc: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-05-29 08:40:03 -07:00
Linus Torvalds
cd86a536c8 Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: avoid back to back on_each_cpu in cpa_flush_array
  x86, relocs: ignore R_386_NONE in kernel relocation entries
2009-05-26 15:06:12 -07:00
Pallipadi, Venkatesh
2171787be2 x86: avoid back to back on_each_cpu in cpa_flush_array
Cleanup cpa_flush_array() to avoid back to back on_each_cpu() calls.

[ Impact: optimizes fix 0af48f42df ]

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-05-26 13:12:12 -07:00
Andreas Herrmann
ca446d0635 [CPUFREQ] powernow-k8: determine exact CPU frequency for HW Pstates
Slightly modified by trenn@suse.de -> only do this on fam 10h and fam 11h.

Currently powernow-k8 determines CPU frequency from ACPI PSS objects, but
according to AMD family 11h BKDG this frequency is just a rounded value:

  "CoreFreq (MHz) = The CPU COF specified by MSRC001_00[6B:64][CpuFid]
  rounded to the nearest 100 Mhz."

As a consequnce powernow-k8 reports wrong CPU frequency on some systems,
e.g. on Turion X2 Ultra:

  powernow-k8: Found 1 AMD Turion(tm)X2 Ultra DualCore Mobile ZM-82
               processors (2 cpu cores) (version 2.20.00)
  powernow-k8:    0 : pstate 0 (2200 MHz)
  powernow-k8:    1 : pstate 1 (1100 MHz)
  powernow-k8:    2 : pstate 2 (600 MHz)

But this is wrong as frequency for Pstate2 is 550 MHz. x86info reports it
correctly:

  #x86info -a |grep Pstate
  ...
  Pstate-0: fid=e, did=0, vid=24 (2200MHz)
  Pstate-1: fid=e, did=1, vid=30 (1100MHz)
  Pstate-2: fid=e, did=2, vid=3c (550MHz) (current)

Solution is to determine the frequency directly from Pstate MSRs instead
of using rounded values from ACPI table.

Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Dave Jones <davej@redhat.com>
2009-05-26 12:04:51 -04:00
Thomas Renninger
df1829770d [CPUFREQ] powernow-k8 cleanup msg if BIOS does not export ACPI _PSS cpufreq data
- Make the message shorter and easier to grep for
- Use printk_once instead of WARN_ONCE (functionality of these was mixed)

Signed-off-by: Thomas Renninger <trenn@suse.de>
Cc: Langsdorf, Mark <mark.langsdorf@amd.com>
Signed-off-by: Dave Jones <davej@redhat.com>
2009-05-26 12:04:51 -04:00
Dave Jones
d38e73e8da [CPUFREQ] powernow-k7 build fix when ACPI=n
arch/x86/kernel/cpu/cpufreq/powernow-k7.c:172: warning: 'invalidate_entry' defined but not used

Reported-by: Toralf Förster <toralf.foerster@gmx.de>
Signed-off-by: Dave Jones <davej@redhat.com>
2009-05-26 12:04:50 -04:00
Jarod Wilson
4319503779 [CPUFREQ] add atom family to p4-clockmod
Some atom procs don't do freq scaling (such as the atom 330 on my own
littlefalls2 board). By adding the atom family here, we at least get
the benefit of passive cooling in a thermal emergency. Not sure how
to see that its actually helping any, but the driver does bind and
claim its functioning on my atom 330.

Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Dave Jones <davej@redhat.com>
2009-05-26 12:04:50 -04:00
Tejun Heo
46176b4f6b x86, relocs: ignore R_386_NONE in kernel relocation entries
For relocatable 32bit kernels, boot/compressed/relocs.c processes
relocation entries in the kernel image and appends it to the kernel
image such that boot/compressed/head_32.S can relocate the kernel.
The kernel image is one statically linked object and only uses two
relocation types - R_386_PC32 and R_386_32, of the two only the latter
needs massaging during kernel relocation and thus handled by relocs.
R_386_PC32 is ignored and all other relocation types are considered
error.

When the target of a relocation resides in a discarded section,
binutils doesn't throw away the relocation record but nullifies it by
changing it to R_386_NONE, which unfortunately makes relocs fail.

The problem was triggered by yet out-of-tree x86 stack unwind patches
but given the binutils behavior, ignoring R_386_NONE is the right
thing to do.

The problem has been tracked down to binutils behavior by Jan Beulich.

[ Impact: fix build with certain binutils by ignoring R_386_NONE ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jan Beulich <JBeulich@novell.com>
Cc: Ingo Molnar <mingo@elte.hu>
LKML-Reference: <4A1B8150.40702@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-05-25 22:52:49 -07:00
Linus Torvalds
b18f1e2199 Merge branch 'kvm-updates/2.6.30' of git://git.kernel.org/pub/scm/virt/kvm/kvm
* 'kvm-updates/2.6.30' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: Fix PDPTR reloading on CR4 writes
  KVM: Make paravirt tlb flush also reload the PAE PDPTRs
2009-05-25 15:51:27 -07:00
Avi Kivity
a2edf57f51 KVM: Fix PDPTR reloading on CR4 writes
The processor is documented to reload the PDPTRs while in PAE mode if any
of the CR4 bits PSE, PGE, or PAE change.  Linux relies on this
behaviour when zapping the low mappings of PAE kernels during boot.

The code already handled changes to CR4.PAE; augment it to also notice changes
to PSE and PGE.

This triggered while booting an F11 PAE kernel; the futex initialization code
runs before any CR3 reloads and writes to a NULL pointer; the futex subsystem
ended up uninitialized, killing PI futexes and pulseaudio which uses them.

Cc: stable@kernel.org
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-05-25 20:00:53 +03:00
Avi Kivity
a8cd0244e9 KVM: Make paravirt tlb flush also reload the PAE PDPTRs
The paravirt tlb flush may be used not only to flush TLBs, but also
to reload the four page-directory-pointer-table entries, as it is used
as a replacement for reloading CR3.  Change the code to do the entire
CR3 reloading dance instead of simply flushing the TLB.

Cc: stable@kernel.org
Signed-off-by: Avi Kivity <avi@redhat.com>
2009-05-25 20:00:50 +03:00
Tejun Heo
71c9d8b68b x86: Remove remap percpu allocator for the time being
Remap percpu allocator has subtle bug when combined with page
attribute changing.  Remap percpu allocator aliases PMD pages for the
first chunk and as pageattr doesn't know about the alias it ends up
updating page attributes of the original mapping thus leaving the
alises in inconsistent state which might lead to subtle data
corruption.  Please read the following threads for more information:

  http://thread.gmane.org/gmane.linux.kernel/835783

The following is the proposed fix which teaches pageattr about percpu
aliases.

  http://thread.gmane.org/gmane.linux.kernel/837157

However, the above changes are deemed too pervasive for upstream
inclusion for 2.6.30 release, so this patch essentially disables
the remap allocator for the time being.

Signed-off-by: Tejun Heo <tj@kernel.org>
LKML-Reference: <4A1A0A27.4050301@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-05-25 05:37:55 +02:00
venkatesh.pallipadi@intel.com
0af48f42df x86: cpa_flush_array wbinvd should be done on all CPUs
cpa_flush_array seems to prefer wbinvd() over clflush at 4M threshold.
clflush needs to be done on only one CPU as per instruction definition.
wbinvd() however, should be done on all CPUs.

[ Impact: fix missing flush which could cause data corruption ]

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-05-22 13:33:59 -07:00
venkatesh.pallipadi@intel.com
0b827537e3 x86: bugfix wbinvd() model check instead of family check
wbinvd is supported on all CPUs 486 or later. But,
pageattr.c is checking x86_model >= 4 before wbinvd(), which looks like
an oversight bug. It was first introduced at one place by changeset
d7c8f21a8c and got copied over to second
place in the same file later.

[ Impact: fix missing cache flush on early-model CPUs, potential data corruption ]

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-05-22 13:33:27 -07:00
Suresh Siddha
0c752a9335 x86: introduce noxsave boot parameter
Introduce "noxsave" boot parameter which will disable the cpu's xsave/xrstor
capabilities. Useful for debugging and working around xsave related issues.

[ Impact: make it possible to debug problems in the field ]

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-05-22 13:10:54 -07:00
H. Peter Anvin
bca23dba76 x86, setup: revert ACPI 3 E820 extended attributes support
Remove ACPI 3 E820 extended memory attributes support.  At least one
vendor actively set all the flags to zero, but left ECX on return at
24.  This bug may be present in other BIOSes.

The breakage functionally means the ACPI 3 flags are probably
completely useless, and that no OS any time soon is going to rely on
their existence.  Therefore, drop support completely.  We may want to
revisit this question in the future, if we find ourselves actually
needing the flags.

This reverts all or part of the following checkins:

     cd670599b7
     c549e71d07

However, retain the part from the latter commit that copies e820 into
a temporary buffer; that is an unrelated BIOS workaround.  Put in a
comment to explain that part.

See https://bugzilla.redhat.com/show_bug.cgi?id=499396 for some
additional information.

[ Impact: detect all memory on affected machines ]

Reported-by: Thomas J. Baker <tjb@unh.edu>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Acked-by: Len Brown <len.brown@intel.com>
Cc: Chuck Ebbert <cebbert@redhat.com>
Cc: Kyle McMartin <kmcmartin@redhat.com>
Cc: Matt Domsch <matt_domsch@dell.com>
2009-05-22 11:14:02 -07:00
Zhang Rui
88dff4936c x86: DMI match for the Sony VGN-Z540N as it needs BIOS reboot
x86: DMI match for the Sony VGN-Z540N as it needs BIOS reboot,
see:

  http://bugzilla.kernel.org/show_bug.cgi?id=12901

[ Impact: fix hung reboot on certain systems ]

Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Cc: Len Brown <lenb@kernel.org>
LKML-Reference: <1242963350.32574.53.camel@rzhang-dt>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-05-22 09:11:30 +02:00
Linus Torvalds
13bba6fda9 Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86: Fix performance regression caused by paravirt_ops on native kernels
  xen: use header for EXPORT_SYMBOL_GPL
  x86, 32-bit: fix kernel_trap_sp()
  x86: fix percpu_{to,from}_op()
  x86: mtrr: Fix high_width computation when phys-addr is >= 44bit
  x86: Fix false positive section mismatch warnings in the apic code
2009-05-18 09:17:37 -07:00
Linus Torvalds
0130b2d701 Merge branch 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  tracing: Append prompt in /debug/tracing/README file
  x86/function-graph: fix constraint for recording old return value
2009-05-18 09:15:41 -07:00
Jeremy Fitzhardinge
b4ecc12699 x86: Fix performance regression caused by paravirt_ops on native kernels
Xiaohui Xin and some other folks at Intel have been looking into what's
behind the performance hit of paravirt_ops when running native.

It appears that the hit is entirely due to the paravirtualized
spinlocks introduced by:

 | commit 8efcbab674
 | Date:   Mon Jul 7 12:07:51 2008 -0700
 |
 |     paravirt: introduce a "lock-byte" spinlock implementation

The extra call/return in the spinlock path is somehow
causing an increase in the cycles/instruction of somewhere around 2-7%
(seems to vary quite a lot from test to test).  The working theory is
that the CPU's pipeline is getting upset about the
call->call->locked-op->return->return, and seems to be failing to
speculate (though I haven't seen anything definitive about the precise
reasons).  This doesn't entirely make sense, because the performance
hit is also visible on unlock and other operations which don't involve
locked instructions.  But spinlock operations clearly swamp all the
other pvops operations, even though I can't imagine that they're
nearly as common (there's only a .05% increase in instructions
executed).

If I disable just the pv-spinlock calls, my tests show that pvops is
identical to non-pvops performance on native (my measurements show that
it is actually about .1% faster, but Xiaohui shows a .05% slowdown).

Summary of results, averaging 10 runs of the "mmperf" test, using a
no-pvops build as baseline:

		nopv		Pv-nospin	Pv-spin
CPU cycles	100.00%		99.89%		102.18%
instructions	100.00%		100.10%		100.15%
CPI		100.00%		99.79%		102.03%
cache ref	100.00%		100.84%		100.28%
cache miss	100.00%		90.47%		88.56%
cache miss rate	100.00%		89.72%		88.31%
branches	100.00%		99.93%		100.04%
branch miss	100.00%		103.66%		107.72%
branch miss rt	100.00%		103.73%		107.67%
wallclock	100.00%		99.90%		102.20%

The clear effect here is that the 2% increase in CPI is
directly reflected in the final wallclock time.

(The other interesting effect is that the more ops are
out of line calls via pvops, the lower the cache access
and miss rates.  Not too surprising, but it suggests that
the non-pvops kernel is over-inlined.  On the flipside,
the branch misses go up correspondingly...)

So, what's the fix?

Paravirt patching turns all the pvops calls into direct calls, so
_spin_lock etc do end up having direct calls.  For example, the compiler
generated code for paravirtualized _spin_lock is:

<_spin_lock+0>:		mov    %gs:0xb4c8,%rax
<_spin_lock+9>:		incl   0xffffffffffffe044(%rax)
<_spin_lock+15>:	callq  *0xffffffff805a5b30
<_spin_lock+22>:	retq

The indirect call will get patched to:
<_spin_lock+0>:		mov    %gs:0xb4c8,%rax
<_spin_lock+9>:		incl   0xffffffffffffe044(%rax)
<_spin_lock+15>:	callq <__ticket_spin_lock>
<_spin_lock+20>:	nop; nop		/* or whatever 2-byte nop */
<_spin_lock+22>:	retq

One possibility is to inline _spin_lock, etc, when building an
optimised kernel (ie, when there's no spinlock/preempt
instrumentation/debugging enabled).  That will remove the outer
call/return pair, returning the instruction stream to a single
call/return, which will presumably execute the same as the non-pvops
case.  The downsides arel 1) it will replicate the
preempt_disable/enable code at eack lock/unlock callsite; this code is
fairly small, but not nothing; and 2) the spinlock definitions are
already a very heavily tangled mass of #ifdefs and other preprocessor
magic, and making any changes will be non-trivial.

The other obvious answer is to disable pv-spinlocks.  Making them a
separate config option is fairly easy, and it would be trivial to
enable them only when Xen is enabled (as the only non-default user).
But it doesn't really address the common case of a distro build which
is going to have Xen support enabled, and leaves the open question of
whether the native performance cost of pv-spinlocks is worth the
performance improvement on a loaded Xen system (10% saving of overall
system CPU when guests block rather than spin).  Still it is a
reasonable short-term workaround.

[ Impact: fix pvops performance regression when running native ]

Analysed-by: "Xin Xiaohui" <xiaohui.xin@intel.com>
Analysed-by: "Li Xin" <xin.li@intel.com>
Analysed-by: "Nakajima Jun" <jun.nakajima@intel.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Xen-devel <xen-devel@lists.xensource.com>
LKML-Reference: <4A0B62F7.5030802@goop.org>
[ fixed the help text ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-05-15 20:07:42 +02:00
Jason Wessel
33ab1979bc kgdb,i386: use address that SP register points to in the exception frame
The treatment of the SP register is different on x86_64 and i386.
This is a regression fix that lived outside the mainline kernel from
2.6.27 to now.  The regression was a result of the original merge
consolidation of the i386 and x86_64 archs to x86.

The incorrectly reported SP on i386 prevented stack tracebacks from
working correctly in gdb.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2009-05-15 07:56:25 -05:00
Steven Rostedt
aa512a27e9 x86/function-graph: fix constraint for recording old return value
After upgrading from gcc 4.2.2 to 4.4.0, the function graph tracer broke.
Investigating, I found that in the asm that replaces the return value,
gcc was using the same register for the old value as it was for the
new value.

	mov	(addr), old
	mov	new, (addr)

But if old and new are the same register, we clobber new with old!
I first thought this was a bug in gcc 4.4.0 and reported it:

  http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40132

Andrew Pinski responded (quickly), saying that it was correct gcc behavior
and the code needed to denote old as an "early clobber".

Instead of "=r"(old), we need "=&r"(old).

[Impact: keep function graph tracer from breaking with gcc 4.4.0 ]

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-05-13 13:52:19 -04:00
Randy Dunlap
44408ad736 xen: use header for EXPORT_SYMBOL_GPL
mmu.c needs to #include module.h to prevent these warnings:

 arch/x86/xen/mmu.c:239: warning: data definition has no type or storage class
 arch/x86/xen/mmu.c:239: warning: type defaults to 'int' in declaration of 'EXPORT_SYMBOL_GPL'
 arch/x86/xen/mmu.c:239: warning: parameter names (without types) in function declaration

[ Impact: cleanup ]

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-05-13 15:43:55 +02:00