linux-stable.git/drivers/vfio, branch v6.1.44

vfio/mdev: Move the compat_class initialization to module init

2023-07-19T14:21:41+00:00

[ Upstream commit ff598081e5b9d0bdd6874bfe340811bbb75b35e4 ]

The pointer to mdev_bus_compat_class is statically defined at the top
of mdev_core, and was originally (commit 7b96953bc640 ("vfio: Mediated
device Core driver") serialized by the parent_list_lock. The blamed
commit removed this mutex, leaving the pointer initialization
unserialized. As a result, the creation of multiple MDEVs in parallel
(such as during boot) can encounter errors during the creation of the
sysfs entries, such as:

  [    8.337509] sysfs: cannot create duplicate filename '/class/mdev_bus'
  [    8.337514] vfio_ccw 0.0.01d8: MDEV: Registered
  [    8.337516] CPU: 13 PID: 946 Comm: driverctl Not tainted 6.4.0-rc7 #20
  [    8.337522] Hardware name: IBM 3906 M05 780 (LPAR)
  [    8.337525] Call Trace:
  [    8.337528]  [<0000000162b0145a>] dump_stack_lvl+0x62/0x80
  [    8.337540]  [<00000001622aeb30>] sysfs_warn_dup+0x78/0x88
  [    8.337549]  [<00000001622aeca6>] sysfs_create_dir_ns+0xe6/0xf8
  [    8.337552]  [<0000000162b04504>] kobject_add_internal+0xf4/0x340
  [    8.337557]  [<0000000162b04d48>] kobject_add+0x78/0xd0
  [    8.337561]  [<0000000162b04e0a>] kobject_create_and_add+0x6a/0xb8
  [    8.337565]  [<00000001627a110e>] class_compat_register+0x5e/0x90
  [    8.337572]  [<000003ff7fd815da>] mdev_register_parent+0x102/0x130 [mdev]
  [    8.337581]  [<000003ff7fdc7f2c>] vfio_ccw_sch_probe+0xe4/0x178 [vfio_ccw]
  [    8.337588]  [<0000000162a7833c>] css_probe+0x44/0x80
  [    8.337599]  [<000000016279f4da>] really_probe+0xd2/0x460
  [    8.337603]  [<000000016279fa08>] driver_probe_device+0x40/0xf0
  [    8.337606]  [<000000016279fb78>] __device_attach_driver+0xc0/0x140
  [    8.337610]  [<000000016279cbe0>] bus_for_each_drv+0x90/0xd8
  [    8.337618]  [<00000001627a00b0>] __device_attach+0x110/0x190
  [    8.337621]  [<000000016279c7c8>] bus_rescan_devices_helper+0x60/0xb0
  [    8.337626]  [<000000016279cd48>] drivers_probe_store+0x48/0x80
  [    8.337632]  [<00000001622ac9b0>] kernfs_fop_write_iter+0x138/0x1f0
  [    8.337635]  [<00000001621e5e14>] vfs_write+0x1ac/0x2f8
  [    8.337645]  [<00000001621e61d8>] ksys_write+0x70/0x100
  [    8.337650]  [<0000000162b2bdc4>] __do_syscall+0x1d4/0x200
  [    8.337656]  [<0000000162b3c828>] system_call+0x70/0x98
  [    8.337664] kobject: kobject_add_internal failed for mdev_bus with -EEXIST, don't try to register things with the same name in the same directory.
  [    8.337668] kobject: kobject_create_and_add: kobject_add error: -17
  [    8.337674] vfio_ccw: probe of 0.0.01d9 failed with error -12
  [    8.342941] vfio_ccw_mdev aeb9ca91-10c6-42bc-a168-320023570aea: Adding to iommu group 2

Move the initialization of the mdev_bus_compat_class pointer to the
init path, to match the cleanup in module exit. This way the code
in mdev_register_parent() can simply link the new parent to it,
rather than determining whether initialization is required first.

Fixes: 89345d5177aa ("vfio/mdev: embedd struct mdev_parent in the parent data structure")
Reported-by: Alexander Egorenkov 
Signed-off-by: Eric Farman 
Reviewed-by: Kevin Tian 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Tony Krowiak 
Reviewed-by: Jason Gunthorpe 
Link: https://lore.kernel.org/r/20230626133642.2939168-1-farman@linux.ibm.com
Signed-off-by: Alex Williamson 
Signed-off-by: Sasha Levin

vfio/type1: check pfn valid before converting to struct page

2023-06-05T07:26:19+00:00

[ Upstream commit 4752354af71043e6fd72ef5490ed6da39e6cab4a ]

Check physical PFN is valid before converting the PFN to a struct page
pointer to be returned to caller of vfio_pin_pages().

vfio_pin_pages() pins user pages with contiguous IOVA.
If the IOVA of a user page to be pinned belongs to vma of vm_flags
VM_PFNMAP, pin_user_pages_remote() will return -EFAULT without returning
struct page address for this PFN. This is because usually this kind of PFN
(e.g. MMIO PFN) has no valid struct page address associated.
Upon this error, vaddr_get_pfns() will obtain the physical PFN directly.

While previously vfio_pin_pages() returns to caller PFN arrays directly,
after commit
34a255e67615 ("vfio: Replace phys_pfn with pages for vfio_pin_pages()"),
PFNs will be converted to "struct page *" unconditionally and therefore
the returned "struct page *" array may contain invalid struct page
addresses.

Given current in-tree users of vfio_pin_pages() only expect "struct page *
returned, check PFN validity and return -EINVAL to let the caller be
aware of IOVAs to be pinned containing PFN not able to be returned in
"struct page *" array. So that, the caller will not consume the returned
pointer (e.g. test PageReserved()) and avoid error like "supervisor read
access in kernel mode".

Fixes: 34a255e67615 ("vfio: Replace phys_pfn with pages for vfio_pin_pages()")
Cc: Sean Christopherson 
Reviewed-by: Jason Gunthorpe 
Signed-off-by: Yan Zhao 
Reviewed-by: Sean Christopherson 
Link: https://lore.kernel.org/r/20230519065843.10653-1-yan.y.zhao@intel.com
Signed-off-by: Alex Williamson 
Signed-off-by: Sasha Levin

vfio/type1: restore locked_vm

2023-03-10T08:34:32+00:00

commit 90fdd158a695d70403163f9a0e4efc5b20f3fd3e upstream.

When a vfio container is preserved across exec or fork-exec, the new
task's mm has a locked_vm count of 0.  After a dma vaddr is updated using
VFIO_DMA_MAP_FLAG_VADDR, locked_vm remains 0, and the pinned memory does
not count against the task's RLIMIT_MEMLOCK.

To restore the correct locked_vm count, when VFIO_DMA_MAP_FLAG_VADDR is
used and the dma's mm has changed, add the dma's locked_vm count to
the new mm->locked_vm, subject to the rlimit, and subtract it from the
old mm->locked_vm.

Fixes: c3cbab24db38 ("vfio/type1: implement interfaces to update vaddr")
Cc: stable@vger.kernel.org
Signed-off-by: Steve Sistare 
Reviewed-by: Kevin Tian 
Reviewed-by: Jason Gunthorpe 
Link: https://lore.kernel.org/r/1675184289-267876-5-git-send-email-steven.sistare@oracle.com
Signed-off-by: Alex Williamson 
Signed-off-by: Greg Kroah-Hartman

vfio/type1: track locked_vm per dma

2023-03-10T08:34:32+00:00

commit 18e292705ba21cc9b3227b9ad5b1c28973605ee5 upstream.

Track locked_vm per dma struct, and create a new subroutine, both for use
in a subsequent patch.  No functional change.

Fixes: c3cbab24db38 ("vfio/type1: implement interfaces to update vaddr")
Cc: stable@vger.kernel.org
Signed-off-by: Steve Sistare 
Reviewed-by: Kevin Tian 
Reviewed-by: Jason Gunthorpe 
Link: https://lore.kernel.org/r/1675184289-267876-4-git-send-email-steven.sistare@oracle.com
Signed-off-by: Alex Williamson 
Signed-off-by: Greg Kroah-Hartman

vfio/type1: prevent underflow of locked_vm via exec()

2023-03-10T08:34:32+00:00

commit 046eca5018f8a5dd1dc2cedf87fb5843b9ea3026 upstream.

When a vfio container is preserved across exec, the task does not change,
but it gets a new mm with locked_vm=0, and loses the count from existing
dma mappings.  If the user later unmaps a dma mapping, locked_vm underflows
to a large unsigned value, and a subsequent dma map request fails with
ENOMEM in __account_locked_vm.

To avoid underflow, grab and save the mm at the time a dma is mapped.
Use that mm when adjusting locked_vm, rather than re-acquiring the saved
task's mm, which may have changed.  If the saved mm is dead, do nothing.

locked_vm is incremented for existing mappings in a subsequent patch.

Fixes: 73fa0d10d077 ("vfio: Type1 IOMMU implementation")
Cc: stable@vger.kernel.org
Signed-off-by: Steve Sistare 
Reviewed-by: Kevin Tian 
Reviewed-by: Jason Gunthorpe 
Link: https://lore.kernel.org/r/1675184289-267876-3-git-send-email-steven.sistare@oracle.com
Signed-off-by: Alex Williamson 
Signed-off-by: Greg Kroah-Hartman

vfio/type1: exclude mdevs from VFIO_UPDATE_VADDR

2023-03-10T08:34:32+00:00

commit ef3a3f6a294ba65fd906a291553935881796f8a5 upstream.

Disable the VFIO_UPDATE_VADDR capability if mediated devices are present.
Their kernel threads could be blocked indefinitely by a misbehaving
userland while trying to pin/unpin pages while vaddrs are being updated.

Do not allow groups to be added to the container while vaddr's are invalid,
so we never need to block user threads from pinning, and can delete the
vaddr-waiting code in a subsequent patch.

Fixes: c3cbab24db38 ("vfio/type1: implement interfaces to update vaddr")
Cc: stable@vger.kernel.org
Signed-off-by: Steve Sistare 
Reviewed-by: Kevin Tian 
Reviewed-by: Jason Gunthorpe 
Link: https://lore.kernel.org/r/1675184289-267876-2-git-send-email-steven.sistare@oracle.com
Signed-off-by: Alex Williamson 
Signed-off-by: Greg Kroah-Hartman

vfio/type1: Respect IOMMU reserved regions in vfio_test_domain_fgsp()

2023-02-01T07:34:36+00:00

[ Upstream commit 895c0747f726bb50c9b7a805613a61d1b6f9fa06 ]

Since commit cbf7827bc5dc ("iommu/s390: Fix potential s390_domain
aperture shrinking") the s390 IOMMU driver uses reserved regions for the
system provided DMA ranges of PCI devices. Previously it reduced the
size of the IOMMU aperture and checked it on each mapping operation.
On current machines the system denies use of DMA addresses below 2^32 for
all PCI devices.

Usually mapping IOVAs in a reserved regions is harmless until a DMA
actually tries to utilize the mapping. However on s390 there is
a virtual PCI device called ISM which is implemented in firmware and
used for cross LPAR communication. Unlike real PCI devices this device
does not use the hardware IOMMU but inspects IOMMU translation tables
directly on IOTLB flush (s390 RPCIT instruction). If it detects IOVA
mappings outside the allowed ranges it goes into an error state. This
error state then causes the device to be unavailable to the KVM guest.

Analysing this we found that vfio_test_domain_fgsp() maps 2 pages at DMA
address 0 irrespective of the IOMMUs reserved regions. Even if usually
harmless this seems wrong in the general case so instead go through the
freshly updated IOVA list and try to find a range that isn't reserved,
and fits 2 pages, is PAGE_SIZE * 2 aligned. If found use that for
testing for fine grained super pages.

Fixes: af029169b8fd ("vfio/type1: Check reserved region conflict and update iova list")
Signed-off-by: Niklas Schnelle 
Reviewed-by: Matthew Rosato 
Reviewed-by: Jason Gunthorpe 
Link: https://lore.kernel.org/r/20230110164427.4051938-2-schnelle@linux.ibm.com
Signed-off-by: Alex Williamson 
Signed-off-by: Sasha Levin

vfio/iova_bitmap: refactor iova_bitmap_set() to better handle page boundaries

2022-12-31T12:32:41+00:00

[ Upstream commit b058ea3ab5afea873ab8d976277539ca9e43869a ]

Commit f38044e5ef58 ("vfio/iova_bitmap: Fix PAGE_SIZE unaligned bitmaps")
had fixed the unaligned bitmaps by capping the remaining iterable set at
the start of the bitmap. Although, that mistakenly worked around
iova_bitmap_set() incorrectly setting bits across page boundary.

Fix this by reworking the loop inside iova_bitmap_set() to iterate over a
range of bits to set (cur_bit .. last_bit) which may span different pinned
pages, thus updating @page_idx and @offset as it sets the bits. The
previous cap to the first page is now adjusted to be always accounted
rather than when there's only a non-zero pgoff.

While at it, make @page_idx , @offset and @nbits to be unsigned int given
that it won't be more than 512 and 4096 respectively (even a bigger
PAGE_SIZE or a smaller struct page size won't make this bigger than the
above 32-bit max). Also, delete the stale kdoc on Return type.

Cc: Avihai Horon 
Fixes: f38044e5ef58 ("vfio/iova_bitmap: Fix PAGE_SIZE unaligned bitmaps")
Co-developed-by: Jason Gunthorpe 
Signed-off-by: Jason Gunthorpe 
Signed-off-by: Joao Martins 
Reviewed-by: Jason Gunthorpe 
Tested-by: Avihai Horon 
Link: https://lore.kernel.org/r/20221129131235.38880-1-joao.m.martins@oracle.com
Signed-off-by: Alex Williamson 
Signed-off-by: Sasha Levin

vfio/iova_bitmap: Fix PAGE_SIZE unaligned bitmaps

2022-12-31T12:32:38+00:00

[ Upstream commit f38044e5ef58ad0346fdabd7027ea5c1e1a3b624 ]

iova_bitmap_set() doesn't consider the end of the page boundary when the
first bitmap page offset isn't zero, and wrongly changes the consecutive
page right after. Consequently this leads to missing dirty pages from
reported by the device as seen from the VMM.

The current logic iterates over a given number of base pages and clamps it
to the remaining indexes to iterate in the last page.  Instead of having to
consider extra pages to pin (e.g. first and extra pages), just handle the
first page as its own range and let the rest of the bitmap be handled as if
it was base page aligned.

This is done by changing iova_bitmap_mapped_remaining() to return PAGE_SIZE
- pgoff (on the first bitmap page), and leads to pgoff being set to 0 on
following iterations.

Fixes: 58ccf0190d19 ("vfio: Add an IOVA bitmap support")
Reported-by: Avihai Horon 
Tested-by: Avihai Horon 
Signed-off-by: Joao Martins 
Link: https://lore.kernel.org/r/20221025193114.58695-3-joao.m.martins@oracle.com
Signed-off-by: Alex Williamson 
Signed-off-by: Sasha Levin

vfio: platform: Do not pass return buffer to ACPI _RST method

2022-12-31T12:32:38+00:00

[ Upstream commit e67e070632a665c932d534b8b800477bb3111449 ]

The ACPI _RST method has no return value, there's no need to pass a return
buffer to acpi_evaluate_object().

Fixes: d30daa33ec1d ("vfio: platform: call _RST method when using ACPI")
Signed-off-by: Rafael Mendonca 
Reviewed-by: Eric Auger 
Link: https://lore.kernel.org/r/20221018152825.891032-1-rafaelmendsr@gmail.com
Signed-off-by: Alex Williamson 
Signed-off-by: Sasha Levin