The vfio_iommu_replay() function does not currently unwind on error,
yet it does pin pages, perform IOMMU mapping, and modify the vfio_dma
structure to indicate IOMMU mapping. The IOMMU mappings are torn down
when the domain is destroyed, but the other actions go on to cause
trouble later. For example, the iommu->domain_list can be empty if we
only have a non-IOMMU backed mdev attached. We don't currently check
if the list is empty before getting the first entry in the list, which
leads to a bogus domain pointer. If a vfio_dma entry is erroneously
marked as iommu_mapped, we'll attempt to use that bogus pointer to
retrieve the existing physical page addresses.
This is the scenario that uncovered this issue, attempting to hot-add
a vfio-pci device to a container with an existing mdev device and DMA
mappings, one of which could not be pinned, causing a failure adding
the new group to the existing container and setting the conditions
for a subsequent attempt to explode.
To resolve this, we can first check if the domain_list is empty so
that we can reject replay of a bogus domain, should we ever encounter
this inconsistent state again in the future. The real fix though is
to add the necessary unwind support, which means cleaning up the
current pinning if an IOMMU mapping fails, then walking back through
the r-b tree of DMA entries, reading from the IOMMU which ranges are
mapped, and unmapping and unpinning those ranges. To be able to do
this, we also defer marking the DMA entry as IOMMU mapped until all
entries are processed, in order to allow the unwind to know the
disposition of each entry.
Fixes: a54eb55045 ("vfio iommu type1: Add support for mediated devices")
Reported-by: Zhiyi Guo <zhguo@redhat.com>
Tested-by: Zhiyi Guo <zhguo@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
A down_read on memory_lock is held when performing read/write accesses
to MMIO BAR space, including across the copy_to/from_user() callouts
which may fault. If the user buffer for these copies resides in an
mmap of device MMIO space, the mmap fault handler will acquire a
recursive read-lock on memory_lock. Avoid this by reducing the lock
granularity. Sequential accesses requiring multiple ioread/iowrite
cycles are expected to be rare, therefore typical accesses should not
see additional overhead.
VGA MMIO accesses are expected to be non-fatal regardless of the PCI
memory enable bit to allow legacy probing, this behavior remains with
a comment added. ioeventfds are now included in memory access testing,
with writes dropped while memory space is disabled.
Fixes: abafbc551f ("vfio-pci: Invalidate mmaps and block MMIO access on disabled memory")
Reported-by: Zhiyi Guo <zhguo@redhat.com>
Tested-by: Zhiyi Guo <zhguo@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
After the cleanup of page fault accounting, gup does not need to pass
task_struct around any more. Remove that parameter in the whole gup
stack.
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Link: http://lkml.kernel.org/r/20200707225021.200906-26-peterx@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch refactors the vfio_iommu_type1_ioctl() to use switch instead of
if-else, and each command got a helper function.
Cc: Kevin Tian <kevin.tian@intel.com>
CC: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Eric Auger <eric.auger@redhat.com>
Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
The current generation of Intel® QuickAssist Technology devices
are not designed to run in an untrusted environment because of the
following issues reported in the document "Intel® QuickAssist Technology
(Intel® QAT) Software for Linux" (document number 336211-014):
QATE-39220 - GEN - Intel® QAT API submissions with bad addresses that
trigger DMA to invalid or unmapped addresses can cause a
platform hang
QATE-7495 - GEN - An incorrectly formatted request to Intel® QAT can
hang the entire Intel® QAT Endpoint
The document is downloadable from https://01.org/intel-quickassist-technology
at the following link:
https://01.org/sites/default/files/downloads/336211-014-qatforlinux-releasenotes-hwv1.7_0.pdf
This patch adds the following QAT devices to the denylist: DH895XCC,
C3XXX and C62X.
Signed-off-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Reviewed-by: Fiona Trahe <fiona.trahe@intel.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Add denylist of devices that by default are not probed by vfio-pci.
Devices in this list may be susceptible to untrusted application, even
if the IOMMU is enabled. To be accessed via vfio-pci, the user has to
explicitly disable the denylist.
The denylist can be disabled via the module parameter disable_denylist.
Signed-off-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Fiona Trahe <fiona.trahe@intel.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
No need to release and immediately re-acquire igate while clearing
out the eventfd ctxs.
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This code was using get_user_pages*(), in a "Case 2" scenario
(DMA/RDMA), using the categorization from [1]. That means that it's
time to convert the get_user_pages*() + put_page() calls to
pin_user_pages*() + unpin_user_pages() calls.
There is some helpful background in [2]: basically, this is a small
part of fixing a long-standing disconnect between pinning pages, and
file systems' use of those pages.
[1] Documentation/core-api/pin_user_pages.rst
[2] "Explicit pinning of user-space pages":
https://lwn.net/Articles/807108/
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Cornelia Huck <cohuck@redhat.com>
Cc: kvm@vger.kernel.org
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Commit c5e6688752 ("vfio/type1: Add conditional rescheduling")
missed a "cond_resched()" in vfio_iommu_map if iommu map failed.
This is a very tiny optimization and the case can hardly happen.
Signed-off-by: Xiang Zheng <zhengxiang9@huawei.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Intel document 333717-008, "Intel® Ethernet Controller X550
Specification Update", version 2.7, dated June 2020, includes errata
#22, added in version 2.1, May 2016, indicating X550 NICs suffer from
the same implementation deficiency as the 700-series NICs:
"The Interrupt Status bit in the Status register of the PCIe
configuration space is not implemented and is not set as described
in the PCIe specification."
Without the interrupt status bit, vfio-pci cannot determine when
these devices signal INTx. They are therefore added to the nointx
quirk.
Cc: Jesse Brandeburg <jesse.brandeburg@intel.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
SR-IOV VFs do not implement the memory enable bit of the command
register, therefore this bit is not set in config space after
pci_enable_device(). This leads to an unintended difference
between PF and VF in hand-off state to the user. We can correct
this by setting the initial value of the memory enable bit in our
virtualized config space. There's really no need however to
ever fault a user on a VF though as this would only indicate an
error in the user's management of the enable bit, versus a PF
where the same access could trigger hardware faults.
Fixes: abafbc551f ("vfio-pci: Invalidate mmaps and block MMIO access on disabled memory")
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
The next use of the device will generate an underflow from the
stale reference.
Cc: Qian Cai <cai@lca.pw>
Fixes: 1518ac272e ("vfio/pci: fix memory leaks of eventfd ctx")
Reported-by: Daniel Wagner <dwagner@suse.de>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Tested-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Switch the function documentation to kerneldoc comments, and add
WARN_ON_ONCE asserts that the calling thread is a kernel thread and does
not have ->mm set (or has ->mm set in the case of unuse_mm).
Also give the functions a kthread_ prefix to better document the use case.
[hch@lst.de: fix a comment typo, cover the newly merged use_mm/unuse_mm caller in vfio]
Link: http://lkml.kernel.org/r/20200416053158.586887-3-hch@lst.de
[sfr@canb.auug.org.au: powerpc/vas: fix up for {un}use_mm() rename]
Link: http://lkml.kernel.org/r/20200422163935.5aa93ba5@canb.auug.org.au
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [usb]
Acked-by: Haren Myneni <haren@linux.ibm.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Felipe Balbi <balbi@kernel.org>
Cc: Jason Wang <jasowang@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: Zhi Wang <zhi.a.wang@intel.com>
Link: http://lkml.kernel.org/r/20200404094101.672954-6-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
cover the newly merged use_mm/unuse_mm caller in vfio
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Felipe Balbi <balbi@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: Zhi Wang <zhi.a.wang@intel.com>
Link: http://lkml.kernel.org/r/20200416053158.586887-2-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Convert the last few remaining mmap_sem rwsem calls to use the new mmap
locking API. These were missed by coccinelle for some reason (I think
coccinelle does not support some of the preprocessor constructs in these
files ?)
[akpm@linux-foundation.org: convert linux-next leftovers]
[akpm@linux-foundation.org: more linux-next leftovers]
[akpm@linux-foundation.org: more linux-next leftovers]
Signed-off-by: Michel Lespinasse <walken@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Liam Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ying Han <yinghan@google.com>
Link: http://lkml.kernel.org/r/20200520052908.204642-6-walken@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- Support for userspace to send requests directly to the on-chip GZIP
accelerator on Power9.
- Rework of our lockless page table walking (__find_linux_pte()) to make it
safe against parallel page table manipulations without relying on an IPI for
serialisation.
- A series of fixes & enhancements to make our machine check handling more
robust.
- Lots of plumbing to add support for "prefixed" (64-bit) instructions on
Power10.
- Support for using huge pages for the linear mapping on 8xx (32-bit).
- Remove obsolete Xilinx PPC405/PPC440 support, and an associated sound driver.
- Removal of some obsolete 40x platforms and associated cruft.
- Initial support for booting on Power10.
- Lots of other small features, cleanups & fixes.
Thanks to:
Alexey Kardashevskiy, Alistair Popple, Andrew Donnellan, Andrey Abramov,
Aneesh Kumar K.V, Balamuruhan S, Bharata B Rao, Bulent Abali, Cédric Le
Goater, Chen Zhou, Christian Zigotzky, Christophe JAILLET, Christophe Leroy,
Dmitry Torokhov, Emmanuel Nicolet, Erhard F., Gautham R. Shenoy, Geoff Levand,
George Spelvin, Greg Kurz, Gustavo A. R. Silva, Gustavo Walbon, Haren Myneni,
Hari Bathini, Joel Stanley, Jordan Niethe, Kajol Jain, Kees Cook, Leonardo
Bras, Madhavan Srinivasan., Mahesh Salgaonkar, Markus Elfring, Michael
Neuling, Michal Simek, Nathan Chancellor, Nathan Lynch, Naveen N. Rao,
Nicholas Piggin, Oliver O'Halloran, Paul Mackerras, Pingfan Liu, Qian Cai, Ram
Pai, Raphael Moreira Zinsly, Ravi Bangoria, Sam Bobroff, Sandipan Das, Segher
Boessenkool, Stephen Rothwell, Sukadev Bhattiprolu, Tyrel Datwyler, Wolfram
Sang, Xiongfeng Wang.
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Merge tag 'powerpc-5.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
- Support for userspace to send requests directly to the on-chip GZIP
accelerator on Power9.
- Rework of our lockless page table walking (__find_linux_pte()) to
make it safe against parallel page table manipulations without
relying on an IPI for serialisation.
- A series of fixes & enhancements to make our machine check handling
more robust.
- Lots of plumbing to add support for "prefixed" (64-bit) instructions
on Power10.
- Support for using huge pages for the linear mapping on 8xx (32-bit).
- Remove obsolete Xilinx PPC405/PPC440 support, and an associated sound
driver.
- Removal of some obsolete 40x platforms and associated cruft.
- Initial support for booting on Power10.
- Lots of other small features, cleanups & fixes.
Thanks to: Alexey Kardashevskiy, Alistair Popple, Andrew Donnellan,
Andrey Abramov, Aneesh Kumar K.V, Balamuruhan S, Bharata B Rao, Bulent
Abali, Cédric Le Goater, Chen Zhou, Christian Zigotzky, Christophe
JAILLET, Christophe Leroy, Dmitry Torokhov, Emmanuel Nicolet, Erhard F.,
Gautham R. Shenoy, Geoff Levand, George Spelvin, Greg Kurz, Gustavo A.
R. Silva, Gustavo Walbon, Haren Myneni, Hari Bathini, Joel Stanley,
Jordan Niethe, Kajol Jain, Kees Cook, Leonardo Bras, Madhavan
Srinivasan., Mahesh Salgaonkar, Markus Elfring, Michael Neuling, Michal
Simek, Nathan Chancellor, Nathan Lynch, Naveen N. Rao, Nicholas Piggin,
Oliver O'Halloran, Paul Mackerras, Pingfan Liu, Qian Cai, Ram Pai,
Raphael Moreira Zinsly, Ravi Bangoria, Sam Bobroff, Sandipan Das, Segher
Boessenkool, Stephen Rothwell, Sukadev Bhattiprolu, Tyrel Datwyler,
Wolfram Sang, Xiongfeng Wang.
* tag 'powerpc-5.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (299 commits)
powerpc/pseries: Make vio and ibmebus initcalls pseries specific
cxl: Remove dead Kconfig options
powerpc: Add POWER10 architected mode
powerpc/dt_cpu_ftrs: Add MMA feature
powerpc/dt_cpu_ftrs: Enable Prefixed Instructions
powerpc/dt_cpu_ftrs: Advertise support for ISA v3.1 if selected
powerpc: Add support for ISA v3.1
powerpc: Add new HWCAP bits
powerpc/64s: Don't set FSCR bits in INIT_THREAD
powerpc/64s: Save FSCR to init_task.thread.fscr after feature init
powerpc/64s: Don't let DT CPU features set FSCR_DSCR
powerpc/64s: Don't init FSCR_DSCR in __init_FSCR()
powerpc/32s: Fix another build failure with CONFIG_PPC_KUAP_DEBUG
powerpc/module_64: Use special stub for _mcount() with -mprofile-kernel
powerpc/module_64: Simplify check for -mprofile-kernel ftrace relocations
powerpc/module_64: Consolidate ftrace code
powerpc/32: Disable KASAN with pages bigger than 16k
powerpc/uaccess: Don't set KUEP by default on book3s/32
powerpc/uaccess: Don't set KUAP by default on book3s/32
powerpc/8xx: Reduce time spent in allow_user_access() and friends
...
Fixes sparse warnings by adding '__user' in typecast for
copy_[from,to]_user()
Fixes: d6a4c18566 ("vfio iommu: Implementation of ioctl for dirty pages tracking")
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Fixes compilation error with ARCH=i386.
Error fixed by this commit:
ld: drivers/vfio/vfio_iommu_type1.o: in function `vfio_dma_populate_bitmap':
>> vfio_iommu_type1.c:(.text+0x666): undefined reference to `__udivdi3'
Fixes: d6a4c18566 ("vfio iommu: Implementation of ioctl for dirty pages tracking")
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
kobject_init_and_add() takes reference even when it fails.
If this function returns an error, kobject_put() must be called to
properly clean up the memory associated with the object. Thus,
replace kfree() by kobject_put() to fix this issue. Previous
commit "b8eb718348b8" fixed a similar problem.
Fixes: 7b96953bc6 ("vfio: Mediated device Core driver")
Signed-off-by: Qiushi Wu <wu000273@umn.edu>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Added a check such that only singleton IOMMU groups can pin pages.
>From the point when vendor driver pins any pages, consider IOMMU group
dirty page scope to be limited to pinned pages.
To optimize to avoid walking list often, added flag
pinned_page_dirty_scope to indicate if all of the vfio_groups for each
vfio_domain in the domain_list dirty page scope is limited to pinned
pages. This flag is updated on first pinned pages request for that IOMMU
group and on attaching/detaching group.
Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Neo Jia <cjia@nvidia.com>
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Added migration capability in IOMMU info chain.
User application should check IOMMU info chain for migration capability
to use dirty page tracking feature provided by kernel module.
User application must check page sizes supported and maximum dirty
bitmap size returned by this capability structure for ioctls used to get
dirty bitmap.
Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
DMA mapped pages, including those pinned by mdev vendor drivers, might
get unpinned and unmapped while migration is active and device is still
running. For example, in pre-copy phase while guest driver could access
those pages, host device or vendor driver can dirty these mapped pages.
Such pages should be marked dirty so as to maintain memory consistency
for a user making use of dirty page tracking.
To get bitmap during unmap, user should allocate memory for bitmap, set
it all zeros, set size of allocated memory, set page size to be
considered for bitmap and set flag VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP.
Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Neo Jia <cjia@nvidia.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
VFIO_IOMMU_DIRTY_PAGES ioctl performs three operations:
- Start dirty pages tracking while migration is active
- Stop dirty pages tracking.
- Get dirty pages bitmap. Its user space application's responsibility to
copy content of dirty pages from source to destination during migration.
To prevent DoS attack, memory for bitmap is allocated per vfio_dma
structure. Bitmap size is calculated considering smallest supported page
size. Bitmap is allocated for all vfio_dmas when dirty logging is enabled
Bitmap is populated for already pinned pages when bitmap is allocated for
a vfio_dma with the smallest supported page size. Update bitmap from
pinning functions when tracking is enabled. When user application queries
bitmap, check if requested page size is same as page size used to
populated bitmap. If it is equal, copy bitmap, but if not equal, return
error.
Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Neo Jia <cjia@nvidia.com>
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Fixed error reported by build bot by changing pgsize type from uint64_t
to size_t.
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Calculate and cache pgsize_bitmap when iommu->domain_list is updated
and iommu->external_domain is set for mdev device.
Add iommu->lock protection when cached pgsize_bitmap is accessed.
Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Reviewed-by: Neo Jia <cjia@nvidia.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
The PCI Code and ID Assignment Specification changed capability ID 0
from reserved to a NULL capability in the v1.1 revision. The NULL
capability is defined to include only the 16-bit capability header,
ie. only the ID and next pointer. Unfortunately vfio-pci creates a
map of config space, where ID 0 is used to reserve the standard type
0 header. Finding an actual capability with this ID therefore results
in a bogus range marked in that map and conflicts with subsequent
capabilities. As this seems to be a dummy capability anyway and we
already support dropping capabilities, let's hide this one rather than
delving into the potentially subtle dependencies within our map.
Seen on an NVIDIA Tesla T4.
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Accessing the disabled memory space of a PCI device would typically
result in a master abort response on conventional PCI, or an
unsupported request on PCI express. The user would generally see
these as a -1 response for the read return data and the write would be
silently discarded, possibly with an uncorrected, non-fatal AER error
triggered on the host. Some systems however take it upon themselves
to bring down the entire system when they see something that might
indicate a loss of data, such as this discarded write to a disabled
memory space.
To avoid this, we want to try to block the user from accessing memory
spaces while they're disabled. We start with a semaphore around the
memory enable bit, where writers modify the memory enable state and
must be serialized, while readers make use of the memory region and
can access in parallel. Writers include both direct manipulation via
the command register, as well as any reset path where the internal
mechanics of the reset may both explicitly and implicitly disable
memory access, and manipulation of the MSI-X configuration, where the
MSI-X vector table resides in MMIO space of the device. Readers
include the read and write file ops to access the vfio device fd
offsets as well as memory mapped access. In the latter case, we make
use of our new vma list support to zap, or invalidate, those memory
mappings in order to force them to be faulted back in on access.
Our semaphore usage will stall user access to MMIO spaces across
internal operations like reset, but the user might experience new
behavior when trying to access the MMIO space while disabled via the
PCI command register. Access via read or write while disabled will
return -EIO and access via memory maps will result in a SIGBUS. This
is expected to be compatible with known use cases and potentially
provides better error handling capabilities than present in the
hardware, while avoiding the more readily accessible and severe
platform error responses that might otherwise occur.
Fixes: CVE-2020-12888
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Rather than calling remap_pfn_range() when a region is mmap'd, setup
a vm_ops handler to support dynamic faulting of the range on access.
This allows us to manage a list of vmas actively mapping the area that
we can later use to invalidate those mappings. The open callback
invalidates the vma range so that all tracking is inserted in the
fault handler and removed in the close handler.
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
With conversion to follow_pfn(), DMA mapping a PFNMAP range depends on
the range being faulted into the vma. Add support to manually provide
that, in the same way as done on KVM with hva_to_pfn_remapped().
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Use follow_pfn() to get the PFN of a PFNMAP VMA instead of assuming that
vma->vm_pgoff holds the base PFN of the VMA. This fixes a bug where
attempting to do VFIO_IOMMU_MAP_DMA on an arbitrary PFNMAP'd region of
memory calculates garbage for the PFN.
Hilariously, this only got detected because the first "PFN" calculated
by vaddr_get_pfn() is PFN 0 (vma->vm_pgoff==0), and iommu_iova_to_phys()
uses PA==0 as an error, which triggers a WARN in vfio_unmap_unpin()
because the translation "failed". PFN 0 is now unconditionally reserved
on x86 in order to mitigate L1TF, which causes is_invalid_reserved_pfn()
to return true and in turns results in vaddr_get_pfn() returning success
for PFN 0. Eventually the bogus calculation runs into PFNs that aren't
reserved and leads to failure in vfio_pin_map_dma(). The subsequent
call to vfio_remove_dma() attempts to unmap PFN 0 and WARNs.
WARNING: CPU: 8 PID: 5130 at drivers/vfio/vfio_iommu_type1.c:750 vfio_unmap_unpin+0x2e1/0x310 [vfio_iommu_type1]
Modules linked in: vfio_pci vfio_virqfd vfio_iommu_type1 vfio ...
CPU: 8 PID: 5130 Comm: sgx Tainted: G W 5.6.0-rc5-705d787c7fee-vfio+ #3
Hardware name: Intel Corporation Mehlow UP Server Platform/Moss Beach Server, BIOS CNLSE2R1.D00.X119.B49.1803010910 03/01/2018
RIP: 0010:vfio_unmap_unpin+0x2e1/0x310 [vfio_iommu_type1]
Code: <0f> 0b 49 81 c5 00 10 00 00 e9 c5 fe ff ff bb 00 10 00 00 e9 3d fe
RSP: 0018:ffffbeb5039ebda8 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff9a55cbf8d480 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff9a52b771c200
RBP: 0000000000000000 R08: 0000000000000040 R09: 00000000fffffff2
R10: 0000000000000001 R11: ffff9a51fa896000 R12: 0000000184010000
R13: 0000000184000000 R14: 0000000000010000 R15: ffff9a55cb66ea08
FS: 00007f15d3830b40(0000) GS:ffff9a55d5600000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000561cf39429e0 CR3: 000000084f75f005 CR4: 00000000003626e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
vfio_remove_dma+0x17/0x70 [vfio_iommu_type1]
vfio_iommu_type1_ioctl+0x9e3/0xa7b [vfio_iommu_type1]
ksys_ioctl+0x92/0xb0
__x64_sys_ioctl+0x16/0x20
do_syscall_64+0x4c/0x180
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f15d04c75d7
Code: <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 81 48 2d 00 f7 d8 64 89 01 48
Fixes: 73fa0d10d0 ("vfio: Type1 IOMMU implementation")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
add parentheses to avoid possible vaddr overflow.
Fixes: a54eb55045 ("vfio iommu type1: Add support for mediated devices")
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
instead of calling __copy_to/from_user(), use copy_to_from_user() to
ensure vaddr range is a valid user address range before accessing them.
Fixes: 8d46c0cca5 ("vfio: introduce vfio_dma_rw to read/write a range of IOVAs")
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
Reported-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
When we try to get an MSI cookie for a VFIO device, that can fail if
CONFIG_IOMMU_DMA is not set. In this case iommu_get_msi_cookie() returns
-ENODEV, and that should not be fatal.
Ignore that case and proceed with the initialisation.
This fixes VFIO with a platform device on the Calxeda Midway (no MSIs).
Fixes: f6810c15cf ("iommu/arm-smmu: Clean up early-probing workarounds")
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Older versions of skiboot only provide a single value in the device
tree property "ibm,mmio-atsd", even when multiple Address Translation
Shoot Down (ATSD) registers are present. This prevents NVLink2 devices
(other than the first) from being used with vfio-pci because vfio-pci
expects to be able to assign a dedicated ATSD register to each NVLink2
device.
However, ATSD registers can be shared among devices. This change
allows vfio-pci to fall back to sharing the register at index 0 if
necessary.
Fixes: 7f92891778 ("vfio_pci: Add NVIDIA GV100GL [Tesla V100 SXM2] subdriver")
Signed-off-by: Sam Bobroff <sbobroff@linux.ibm.com>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
The cleanup is getting a tad long.
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
It currently results in messages like:
"vfio-pci 0000:03:00.0: vfio_pci: ..."
Which is quite a bit redundant.
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Gustavo A. R. Silva