linux.git/drivers/vfio/pci, branch v5.8

vfio/pci: fix racy on error and request eventfd ctx

2020-07-17T14:28:40+00:00

The vfio_pci_release call will free and clear the error and request
eventfd ctx while these ctx could be in use at the same time in the
function like vfio_pci_request, and it's expected to protect them under
the vdev->igate mutex, which is missing in vfio_pci_release.

This issue is introduced since commit 1518ac272e78 ("vfio/pci: fix memory
leaks of eventfd ctx"),and since commit 5c5866c593bb ("vfio/pci: Clear
error and request eventfd ctx after releasing"), it's very easily to
trigger the kernel panic like this:

[ 9513.904346] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000008
[ 9513.913091] Mem abort info:
[ 9513.915871]   ESR = 0x96000006
[ 9513.918912]   EC = 0x25: DABT (current EL), IL = 32 bits
[ 9513.924198]   SET = 0, FnV = 0
[ 9513.927238]   EA = 0, S1PTW = 0
[ 9513.930364] Data abort info:
[ 9513.933231]   ISV = 0, ISS = 0x00000006
[ 9513.937048]   CM = 0, WnR = 0
[ 9513.940003] user pgtable: 4k pages, 48-bit VAs, pgdp=0000007ec7d12000
[ 9513.946414] [0000000000000008] pgd=0000007ec7d13003, p4d=0000007ec7d13003, pud=0000007ec728c003, pmd=0000000000000000
[ 9513.956975] Internal error: Oops: 96000006 [#1] PREEMPT SMP
[ 9513.962521] Modules linked in: vfio_pci vfio_virqfd vfio_iommu_type1 vfio hclge hns3 hnae3 [last unloaded: vfio_pci]
[ 9513.972998] CPU: 4 PID: 1327 Comm: bash Tainted: G        W         5.8.0-rc4+ #3
[ 9513.980443] Hardware name: Huawei TaiShan 2280 V2/BC82AMDC, BIOS 2280-V2 CS V3.B270.01 05/08/2020
[ 9513.989274] pstate: 80400089 (Nzcv daIf +PAN -UAO BTYPE=--)
[ 9513.994827] pc : _raw_spin_lock_irqsave+0x48/0x88
[ 9513.999515] lr : eventfd_signal+0x6c/0x1b0
[ 9514.003591] sp : ffff800038a0b960
[ 9514.006889] x29: ffff800038a0b960 x28: ffff007ef7f4da10
[ 9514.012175] x27: ffff207eefbbfc80 x26: ffffbb7903457000
[ 9514.017462] x25: ffffbb7912191000 x24: ffff007ef7f4d400
[ 9514.022747] x23: ffff20be6e0e4c00 x22: 0000000000000008
[ 9514.028033] x21: 0000000000000000 x20: 0000000000000000
[ 9514.033321] x19: 0000000000000008 x18: 0000000000000000
[ 9514.038606] x17: 0000000000000000 x16: ffffbb7910029328
[ 9514.043893] x15: 0000000000000000 x14: 0000000000000001
[ 9514.049179] x13: 0000000000000000 x12: 0000000000000002
[ 9514.054466] x11: 0000000000000000 x10: 0000000000000a00
[ 9514.059752] x9 : ffff800038a0b840 x8 : ffff007ef7f4de60
[ 9514.065038] x7 : ffff007fffc96690 x6 : fffffe01faffb748
[ 9514.070324] x5 : 0000000000000000 x4 : 0000000000000000
[ 9514.075609] x3 : 0000000000000000 x2 : 0000000000000001
[ 9514.080895] x1 : ffff007ef7f4d400 x0 : 0000000000000000
[ 9514.086181] Call trace:
[ 9514.088618]  _raw_spin_lock_irqsave+0x48/0x88
[ 9514.092954]  eventfd_signal+0x6c/0x1b0
[ 9514.096691]  vfio_pci_request+0x84/0xd0 [vfio_pci]
[ 9514.101464]  vfio_del_group_dev+0x150/0x290 [vfio]
[ 9514.106234]  vfio_pci_remove+0x30/0x128 [vfio_pci]
[ 9514.111007]  pci_device_remove+0x48/0x108
[ 9514.115001]  device_release_driver_internal+0x100/0x1b8
[ 9514.120200]  device_release_driver+0x28/0x38
[ 9514.124452]  pci_stop_bus_device+0x68/0xa8
[ 9514.128528]  pci_stop_and_remove_bus_device+0x20/0x38
[ 9514.133557]  pci_iov_remove_virtfn+0xb4/0x128
[ 9514.137893]  sriov_disable+0x3c/0x108
[ 9514.141538]  pci_disable_sriov+0x28/0x38
[ 9514.145445]  hns3_pci_sriov_configure+0x48/0xb8 [hns3]
[ 9514.150558]  sriov_numvfs_store+0x110/0x198
[ 9514.154724]  dev_attr_store+0x44/0x60
[ 9514.158373]  sysfs_kf_write+0x5c/0x78
[ 9514.162018]  kernfs_fop_write+0x104/0x210
[ 9514.166010]  __vfs_write+0x48/0x90
[ 9514.169395]  vfs_write+0xbc/0x1c0
[ 9514.172694]  ksys_write+0x74/0x100
[ 9514.176079]  __arm64_sys_write+0x24/0x30
[ 9514.179987]  el0_svc_common.constprop.4+0x110/0x200
[ 9514.184842]  do_el0_svc+0x34/0x98
[ 9514.188144]  el0_svc+0x14/0x40
[ 9514.191185]  el0_sync_handler+0xb0/0x2d0
[ 9514.195088]  el0_sync+0x140/0x180
[ 9514.198389] Code: b9001020 d2800000 52800022 f9800271 (885ffe61)
[ 9514.204455] ---[ end trace 648de00c8406465f ]---
[ 9514.212308] note: bash[1327] exited with preempt_count 1

Cc: Qian Cai 
Cc: Alex Williamson 
Fixes: 1518ac272e78 ("vfio/pci: fix memory leaks of eventfd ctx")
Signed-off-by: Zeng Tao 
Signed-off-by: Alex Williamson

vfio/pci: Fix SR-IOV VF handling with MMIO blocking

2020-06-25T17:04:23+00:00

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: abafbc551fdd ("vfio-pci: Invalidate mmaps and block MMIO access on disabled memory")
Signed-off-by: Alex Williamson

vfio/pci: Clear error and request eventfd ctx after releasing

2020-06-17T21:18:42+00:00

The next use of the device will generate an underflow from the
stale reference.

Cc: Qian Cai 
Fixes: 1518ac272e78 ("vfio/pci: fix memory leaks of eventfd ctx")
Reported-by: Daniel Wagner 
Reviewed-by: Cornelia Huck 
Tested-by: Daniel Wagner 
Signed-off-by: Alex Williamson

mmap locking API: convert mmap_sem comments

2020-06-09T16:39:14+00:00

Convert comments that reference mmap_sem to reference mmap_lock instead.

[akpm@linux-foundation.org: fix up linux-next leftovers]
[akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil]
[akpm@linux-foundation.org: more linux-next fixups, per Michel]

Signed-off-by: Michel Lespinasse 
Signed-off-by: Andrew Morton 
Reviewed-by: Vlastimil Babka 
Reviewed-by: Daniel Jordan 
Cc: Davidlohr Bueso 
Cc: David Rientjes 
Cc: Hugh Dickins 
Cc: Jason Gunthorpe 
Cc: Jerome Glisse 
Cc: John Hubbard 
Cc: Laurent Dufour 
Cc: Liam Howlett 
Cc: Matthew Wilcox 
Cc: Peter Zijlstra 
Cc: Ying Han 
Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com
Signed-off-by: Linus Torvalds

mmap locking API: convert mmap_sem call sites missed by coccinelle

2020-06-09T16:39:14+00:00

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 
Signed-off-by: Andrew Morton 
Reviewed-by: Daniel Jordan 
Reviewed-by: Laurent Dufour 
Reviewed-by: Vlastimil Babka 
Cc: Davidlohr Bueso 
Cc: David Rientjes 
Cc: Hugh Dickins 
Cc: Jason Gunthorpe 
Cc: Jerome Glisse 
Cc: John Hubbard 
Cc: Liam Howlett 
Cc: Matthew Wilcox 
Cc: Peter Zijlstra 
Cc: Ying Han 
Link: http://lkml.kernel.org/r/20200520052908.204642-6-walken@google.com
Signed-off-by: Linus Torvalds

Merge tag 'vfio-v5.8-rc1' of git://github.com/awilliam/linux-vfio

2020-06-05T20:51:49+00:00

Pull VFIO updates from Alex Williamson:

 - Block accesses to disabled MMIO space (Alex Williamson)

 - VFIO device migration API (Kirti Wankhede)

 - type1 IOMMU dirty bitmap API and implementation (Kirti Wankhede)

 - PCI NULL capability masking (Alex Williamson)

 - Memory leak fixes (Qian Cai)

 - Reference leak fix (Qiushi Wu)

* tag 'vfio-v5.8-rc1' of git://github.com/awilliam/linux-vfio:
  vfio iommu: typecast corrections
  vfio iommu: Use shift operation for 64-bit integer division
  vfio/mdev: Fix reference count leak in add_mdev_supported_type
  vfio: Selective dirty page tracking if IOMMU backed device pins pages
  vfio iommu: Add migration capability to report supported features
  vfio iommu: Update UNMAP_DMA ioctl to get dirty bitmap before unmap
  vfio iommu: Implementation of ioctl for dirty pages tracking
  vfio iommu: Add ioctl definition for dirty pages tracking
  vfio iommu: Cache pgsize_bitmap in struct vfio_iommu
  vfio iommu: Remove atomicity of ref_count of pinned pages
  vfio: UAPI for migration interface for device state
  vfio/pci: fix memory leaks of eventfd ctx
  vfio/pci: fix memory leaks in alloc_perm_bits()
  vfio-pci: Mask cap zero
  vfio-pci: Invalidate mmaps and block MMIO access on disabled memory
  vfio-pci: Fault mmaps to enable vma tracking
  vfio/type1: Support faulting PFNMAP vmas

Merge branches 'v5.8/vfio/alex-block-mmio-v3', 'v5.8/vfio/alex-zero-cap-v2' and 'v5.8/vfio/qian-leak-fixes' into v5.8/vfio/next

2020-05-26T16:27:15+00:00

vfio/pci: fix memory leaks of eventfd ctx

2020-05-26T16:23:22+00:00

Finished a qemu-kvm (-device vfio-pci,host=0001:01:00.0) triggers a few
memory leaks after a while because vfio_pci_set_ctx_trigger_single()
calls eventfd_ctx_fdget() without the matching eventfd_ctx_put() later.
Fix it by calling eventfd_ctx_put() for those memory in
vfio_pci_release() before vfio_device_release().

unreferenced object 0xebff008981cc2b00 (size 128):
  comm "qemu-kvm", pid 4043, jiffies 4294994816 (age 9796.310s)
  hex dump (first 32 bytes):
    01 00 00 00 6b 6b 6b 6b 00 00 00 00 ad 4e ad de  ....kkkk.....N..
    ff ff ff ff 6b 6b 6b 6b ff ff ff ff ff ff ff ff  ....kkkk........
  backtrace:
    [<00000000917e8f8d>] slab_post_alloc_hook+0x74/0x9c
    [<00000000df0f2aa2>] kmem_cache_alloc_trace+0x2b4/0x3d4
    [<000000005fcec025>] do_eventfd+0x54/0x1ac
    [<0000000082791a69>] __arm64_sys_eventfd2+0x34/0x44
    [<00000000b819758c>] do_el0_svc+0x128/0x1dc
    [<00000000b244e810>] el0_sync_handler+0xd0/0x268
    [<00000000d495ef94>] el0_sync+0x164/0x180
unreferenced object 0x29ff008981cc4180 (size 128):
  comm "qemu-kvm", pid 4043, jiffies 4294994818 (age 9796.290s)
  hex dump (first 32 bytes):
    01 00 00 00 6b 6b 6b 6b 00 00 00 00 ad 4e ad de  ....kkkk.....N..
    ff ff ff ff 6b 6b 6b 6b ff ff ff ff ff ff ff ff  ....kkkk........
  backtrace:
    [<00000000917e8f8d>] slab_post_alloc_hook+0x74/0x9c
    [<00000000df0f2aa2>] kmem_cache_alloc_trace+0x2b4/0x3d4
    [<000000005fcec025>] do_eventfd+0x54/0x1ac
    [<0000000082791a69>] __arm64_sys_eventfd2+0x34/0x44
    [<00000000b819758c>] do_el0_svc+0x128/0x1dc
    [<00000000b244e810>] el0_sync_handler+0xd0/0x268
    [<00000000d495ef94>] el0_sync+0x164/0x180

Signed-off-by: Qian Cai 
Signed-off-by: Alex Williamson

vfio/pci: fix memory leaks in alloc_perm_bits()

2020-05-18T15:58:28+00:00

vfio_pci_disable() calls vfio_config_free() but forgets to call
free_perm_bits() resulting in memory leaks,

unreferenced object 0xc000000c4db2dee0 (size 16):
  comm "qemu-kvm", pid 4305, jiffies 4295020272 (age 3463.780s)
  hex dump (first 16 bytes):
    00 00 ff 00 ff ff ff ff ff ff ff ff ff ff 00 00  ................
  backtrace:
    [<00000000a6a4552d>] alloc_perm_bits+0x58/0xe0 [vfio_pci]
    [<00000000ac990549>] vfio_config_init+0xdf0/0x11b0 [vfio_pci]
    init_pci_cap_msi_perm at drivers/vfio/pci/vfio_pci_config.c:1125
    (inlined by) vfio_msi_cap_len at drivers/vfio/pci/vfio_pci_config.c:1180
    (inlined by) vfio_cap_len at drivers/vfio/pci/vfio_pci_config.c:1241
    (inlined by) vfio_cap_init at drivers/vfio/pci/vfio_pci_config.c:1468
    (inlined by) vfio_config_init at drivers/vfio/pci/vfio_pci_config.c:1707
    [<000000006db873a1>] vfio_pci_open+0x234/0x700 [vfio_pci]
    [<00000000630e1906>] vfio_group_fops_unl_ioctl+0x8e0/0xb84 [vfio]
    [<000000009e34c54f>] ksys_ioctl+0xd8/0x130
    [<000000006577923d>] sys_ioctl+0x28/0x40
    [<000000006d7b1cf2>] system_call_exception+0x114/0x1e0
    [<0000000008ea7dd5>] system_call_common+0xf0/0x278
unreferenced object 0xc000000c4db2e330 (size 16):
  comm "qemu-kvm", pid 4305, jiffies 4295020272 (age 3463.780s)
  hex dump (first 16 bytes):
    00 ff ff 00 ff ff ff ff ff ff ff ff ff ff 00 00  ................
  backtrace:
    [<000000004c71914f>] alloc_perm_bits+0x44/0xe0 [vfio_pci]
    [<00000000ac990549>] vfio_config_init+0xdf0/0x11b0 [vfio_pci]
    [<000000006db873a1>] vfio_pci_open+0x234/0x700 [vfio_pci]
    [<00000000630e1906>] vfio_group_fops_unl_ioctl+0x8e0/0xb84 [vfio]
    [<000000009e34c54f>] ksys_ioctl+0xd8/0x130
    [<000000006577923d>] sys_ioctl+0x28/0x40
    [<000000006d7b1cf2>] system_call_exception+0x114/0x1e0
    [<0000000008ea7dd5>] system_call_common+0xf0/0x278

Fixes: 89e1f7d4c66d ("vfio: Add PCI device driver")
Signed-off-by: Qian Cai 
[aw: rolled in follow-up patch]
Signed-off-by: Alex Williamson

vfio-pci: Mask cap zero

2020-05-18T15:55:35+00:00

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 
Signed-off-by: Alex Williamson