size_t is an unsigned type, thus the error case is never reached in
the below call to pread. If bytes is negative, it will be seen as
a very high positive value.
Spotted by Coverity.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Somehow these GPUs manage not to respond to a PCI bus reset, removing
our primary mechanism for resetting graphics cards. The result is
that these devices typically work well for a single VM boot. If the
VM is rebooted or restarted, the guest driver is not able to init the
card from the dirty state, resulting in a blue screen for Windows
guests.
The workaround is to use a device specific reset. This is not 100%
reliable though since it depends on the incoming state of the device,
but it substantially improves the usability of these devices in a VM.
Credit to Alex Deucher <alexander.deucher@amd.com> for his guidance.
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This is an impossible error path due to the fact that we're reading a
kernel provided, rather than user provided link, which will certainly
always fit in PATH_MAX. Currently it returns a fixed 26 char path
plus %d group number, which typically maxes out at double digits.
However, the caller of the initfn certainly expects a less-than zero
return value on error, not just a non-zero value. Therefore we
should correct the sign here.
Reported-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
In an analysis by Laszlo, the resulting type of our calculation for
the end of the MSI-X table, and thus the start of memory after the
table, is uint32_t. We're therefore not correctly preventing the
corner case overflow that we intended to fix here where a BAR >=4G
could place the MSI-X table to end exactly at the 4G boundary. The
MSI-X table offset is defined by the hardware spec to 32bits, so we
simply use a cast rather than changing data structure types. This
scenario is purely theoretically, typically the MSI-X table is located
at the front of the BAR.
Reported-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Rather than retaining io_mem_read/write as simple wrappers around
the memory_region_dispatch_read/write functions, make the latter
public and change all the callers to use them, since we need to
touch all the callsites anyway to add MemTxAttrs and MemTxResult
support. Delete io_mem_read and io_mem_write entirely.
(All the callers currently pass MEMTXATTRS_UNSPECIFIED
and convert the return value back to bool or ignore it.)
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Linux v4.0-rc1 vfio-pci introduced a new virtual interrupt to allow
the kernel to request a device from the user. When signaled, QEMU
will by default attmempt to hot-unplug the device. This is a one-
shot attempt with the expectation that the kernel will continue to
poll for the device if it is not returned. Returning the device when
requested is the expected standard model of cooperative usage, but we
also add an option option to disable this feature. Initially this
opt-out is set as an experimental option because we really should
honor kernel requests for the device.
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Disabling MMAP support uses the slower read/write accesses but allows to
trace all MMIO accesses, which is not good for performance, but very
useful for reverse engineering PCI drivers. This option allows to
disable MMAP per device without a compile-time change.
Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This fixes a compiler error which occurs if DEBUG_VFIO is defined.
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
In the case of VFIO, the unrealize callback is too early to munmap the
BARs. The munmap must be delayed until memory accesses are complete.
To do this, split vfio_unmap_bars in two. The removal step, now called
vfio_unregister_bars, remains in vfio_exitfn. The reclamation step
is vfio_unmap_bars and is moved to the instance_finalize callback.
Similarly, quirk MemoryRegions have to be removed during
vfio_unregister_bars, but freeing the data structure must be delayed
to vfio_unmap_bars.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
In order to enable out-of-BQL address space lookup, destruction of
devices needs to be split in two phases.
Unrealize is the first phase; once it complete no new accesses will
be started, but there may still be pending memory accesses can still
be completed.
The second part is freeing the device, which only happens once all memory
accesses are complete. At this point the reference count has dropped to
zero, an RCU grace period must have completed (because the RCU-protected
FlatViews hold a reference to the device via memory_region_ref). This is
when instance_finalize is called.
Freeing data belongs in an instance_finalize callback, because the
dynamically allocated memory can still be used after unrealize by the
pending memory accesses.
This starts the process by creating an instance_finalize callback and
freeing most of the dynamically-allocated data in instance_finalize.
Because instance_finalize is also called on error paths or also when
the device is actually not realized, the common code needs some changes
to be ready for this. The error path in vfio_initfn can be simplified too.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Now that vfio_put_base_device is called unconditionally at instance_finalize
time, it can be called twice if vfio_populate_device fails. This works
but it is slightly harder to follow.
Change vfio_get_device to not touch the vbasedev struct until it will
definitely succeed, moving the vfio_populate_device call back to vfio-pci.
This way, vfio_put_base_device will only be called once.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Commit d8d9581460 added explicit object_unparent() calls for
dynamically allocated MemoryRegions. The VFIOMSIXInfo structure also
contains such a MemoryRegion, covering the mmap'd region of a PCI BAR
above the MSI-X table. This structure is freed as part of the class
exit function and therefore also needs an explicit object_unparent().
Failing to do this results in random segfaults due to fields within
the structure, often the class pointer, being reclaimed and corrupted
by the time object_finalize_child_property() is called for the object.
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: qemu-stable@nongnu.org # 2.2
When disabling MSI/X interrupts the disable functions will leave the
device in INTx mode (when available). This matches how hardware
operates, INTx is enabled unless MSI/X is enabled (DisINTx is handled
separately). Therefore when we really want to disable all interrupts,
such as when removing the device, and we start with the device in
MSI/X mode, we need to pass through INTx on our way to being
completely quiesced.
In well behaved situations, the guest driver will have shutdown the
device and it will start vfio_exitfn() in INTx mode, producing the
desired result. If hot-unplug causes the guest to crash, we may get
the device in MSI/X state, which will leave QEMU with a bogus handler
installed.
Fix this by re-ordering our disable routine so that it should always
finish in VFIO_INT_NONE state, which is what all callers expect.
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
We use an unsigned int when working with the PCI BAR size, which can
obviously overflow if the BAR is 4GB or larger. This needs to change
to a fixed length uint64_t. A similar issue is possible, though even
more unlikely, when mapping the region above an MSI-X table. The
start of the MSI-X vector table must be below 4GB, but the end, and
therefore the start of the next mapping region, could still land at
4GB.
Suggested-by: Nishank Trivedi <nishank.trivedi@netapp.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Reviewed-by: Don Slutz <dslutz@verizon.com>
Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru>
With the conversion to tracepoints, a couple previous DPRINTKs are
now quite a bit more visible and are really just informational.
Remove these and add a bit more description to another.
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
A new common module is created. It implements all functions
that have no device specificity (PCI, Platform).
This patch only consists in move (no functional changes)
Signed-off-by: Kim Phillips <kim.phillips@linaro.org>
Signed-off-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
vfio_get_device now takes a VFIODevice as argument. The function is split
into 2 parts: vfio_get_device which is generic and vfio_populate_device
which is bus specific.
3 new fields are introduced in VFIODevice to store dev_info.
vfio_put_base_device is created.
Signed-off-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This structure is going to be shared by VFIOPCIDevice and
VFIOPlatformDevice. VFIOBAR includes it.
vfio_eoi becomes an ops of VFIODevice specialized by parent device.
This makes possible to transform vfio_bar_write/read into generic
vfio_region_write/read that will be used by VFIOPlatformDevice too.
vfio_mmap_bar becomes vfio_map_region
Signed-off-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Since we can potentially have both PCI and platform devices in
the same VFIO group, this latter now owns a list of VFIODevices.
A unified reset handler, vfio_reset_handler, is registered, looping
through this VFIODevice list. 2 specialized operations are introduced
(vfio_compute_needs_reset and vfio_hot_reset_multi): they allow to
implement type specific behavior. also reset_works and needs_reset
VFIOPCIDevice fields are moved into VFIODevice.
Signed-off-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Add 3 new fields in the VFIODevice struct. Type is set to
VFIO_DEVICE_TYPE_PCI. The type enum value will later be used
to discriminate between VFIO PCI and platform devices. The name is
set to domain🚌slot:function. Currently used to test whether
the device already is attached to the group. Later on, the name
will be used to simplify all traces. The group is simply moved
from VFIOPCIDevice to VFIODevice.
Signed-off-by: Eric Auger <eric.auger@linaro.org>
[Fix g_strdup_printf() usage]
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Introduce a new base VFIODevice strcut that will be used by both PCI
and Platform VFIO device. Move VFIOPCIDevice fd field there. Obviously
other fields from VFIOPCIDevice will be moved there but this patch
file is introduced to ease the review.
Also vfio_mask_single_irqindex, vfio_unmask_single_irqindex,
vfio_disable_irqindex now take a VFIODevice handle as argument.
Signed-off-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
To prepare for platform device introduction, rename vfio_mask_intx
and vfio_unmask_intx into vfio_mask_single_irqindex and respectively
unmask_single_irqindex. Also use a nex index parameter.
With that name and prototype the function will be usable for other
indexes than VFIO_PCI_INTX_IRQ_INDEX.
Signed-off-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This prepares for the introduction of VFIOPlatformDevice
Signed-off-by: Eric Auger <eric.auger@linaro.org>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This is done in preparation for the addition of VFIO platform
device support.
Signed-off-by: Kim Phillips <kim.phillips@linaro.org>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
