linux-stable.git/drivers/vfio, branch v6.18

vfio/type1: handle DMA map/unmap up to the addressable limit

2025-10-28T21:54:41+00:00

Before this commit, it was possible to create end of address space
mappings, but unmapping them via VFIO_IOMMU_UNMAP_DMA, replaying them
for newly added iommu domains, and querying their dirty pages via
VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP was broken due to bugs caused by
comparisons against (iova + size) expressions, which overflow to zero.
Additionally, there appears to be a page pinning leak in the
vfio_iommu_type1_release() path, since vfio_unmap_unpin()'s loop body
where unmap_unpin_*() are called will never be entered due to overflow
of (iova + size) to zero.

This commit handles DMA map/unmap operations up to the addressable
limit by comparing against inclusive end-of-range limits, and changing
iteration to perform relative traversals across range sizes, rather than
absolute traversals across addresses.

vfio_link_dma() inserts a zero-sized vfio_dma into the rb-tree, and is
only used for that purpose, so discard the size from consideration for
the insertion point.

Tested-by: Alejandro Jimenez 
Fixes: 73fa0d10d077 ("vfio: Type1 IOMMU implementation")
Reviewed-by: Jason Gunthorpe 
Reviewed-by: Alejandro Jimenez 
Signed-off-by: Alex Mastro 
Link: https://lore.kernel.org/r/20251028-fix-unmap-v6-3-2542b96bcc8e@fb.com
Signed-off-by: Alex Williamson

vfio/type1: move iova increment to unmap_unpin_*() caller

2025-10-28T21:54:41+00:00

Move incrementing iova to the caller of these functions as part of
preparing to handle end of address space map/unmap.

Tested-by: Alejandro Jimenez 
Fixes: 73fa0d10d077 ("vfio: Type1 IOMMU implementation")
Reviewed-by: Jason Gunthorpe 
Reviewed-by: Alejandro Jimenez 
Signed-off-by: Alex Mastro 
Link: https://lore.kernel.org/r/20251028-fix-unmap-v6-2-2542b96bcc8e@fb.com
Signed-off-by: Alex Williamson

vfio/type1: sanitize for overflow using check_*_overflow()

2025-10-28T21:54:41+00:00

Adopt check_*_overflow() functions to clearly express overflow check
intent.

Tested-by: Alejandro Jimenez 
Fixes: 73fa0d10d077 ("vfio: Type1 IOMMU implementation")
Reviewed-by: Jason Gunthorpe 
Reviewed-by: Alejandro Jimenez 
Signed-off-by: Alex Mastro 
Link: https://lore.kernel.org/r/20251028-fix-unmap-v6-1-2542b96bcc8e@fb.com
Signed-off-by: Alex Williamson

vfio: Dump migration features under debugfs

2025-10-06T17:22:48+00:00

A debugfs directory was recently added for VFIO devices. Add a new
"features" file under the migration sub-directory to expose which
features the device supports.

Signed-off-by: Cédric Le Goater 
Link: https://lore.kernel.org/r/20250918121928.1921871-1-clg@redhat.com
Signed-off-by: Alex Williamson

vfio/type1: optimize vfio_unpin_pages_remote()

2025-10-06T17:21:27+00:00

When vfio_unpin_pages_remote() is called with a range of addresses that
includes large folios, the function currently performs individual
put_pfn() operations for each page. This can lead to significant
performance overheads, especially when dealing with large ranges of pages.

It would be very rare for reserved PFNs and non reserved will to be mixed
within the same range. So this patch utilizes the has_rsvd variable
introduced in the previous patch to determine whether batch put_pfn()
operations can be performed. Moreover, compared to put_pfn(),
unpin_user_page_range_dirty_lock() is capable of handling large folio
scenarios more efficiently.

The performance test results for completing the 16G VFIO IOMMU DMA
unmapping are as follows.

Base(v6.16):
------- AVERAGE (MADV_HUGEPAGE) --------
VFIO UNMAP DMA in 0.141 s (113.7 GB/s)
------- AVERAGE (MAP_POPULATE) --------
VFIO UNMAP DMA in 0.307 s (52.2 GB/s)
------- AVERAGE (HUGETLBFS) --------
VFIO UNMAP DMA in 0.135 s (118.6 GB/s)

With this patchset:
------- AVERAGE (MADV_HUGEPAGE) --------
VFIO UNMAP DMA in 0.044 s (363.2 GB/s)
------- AVERAGE (MAP_POPULATE) --------
VFIO UNMAP DMA in 0.289 s (55.3 GB/s)
------- AVERAGE (HUGETLBFS) --------
VFIO UNMAP DMA in 0.044 s (361.3 GB/s)

For large folio, we achieve an over 67% performance improvement in
the VFIO UNMAP DMA item. For small folios, the performance test
results appear to show a slight improvement.

Suggested-by: Jason Gunthorpe 
Signed-off-by: Li Zhe 
Reviewed-by: David Hildenbrand 
Acked-by: David Hildenbrand 
Link: https://lore.kernel.org/r/20250814064714.56485-6-lizhe.67@bytedance.com
Signed-off-by: Alex Williamson

vfio/type1: introduce a new member has_rsvd for struct vfio_dma

2025-10-06T17:21:26+00:00

Introduce a new member has_rsvd for struct vfio_dma. This member is
used to indicate whether there are any reserved or invalid pfns in
the region represented by this vfio_dma. If it is true, it indicates
that there is at least one pfn in this region that is either reserved
or invalid.

Signed-off-by: Li Zhe 
Reviewed-by: David Hildenbrand 
Link: https://lore.kernel.org/r/20250814064714.56485-5-lizhe.67@bytedance.com
Signed-off-by: Alex Williamson

vfio/type1: batch vfio_find_vpfn() in function vfio_unpin_pages_remote()

2025-10-06T17:21:26+00:00

The function vpfn_pages() can help us determine the number of vpfn
nodes on the vpfn rb tree within a specified range. This allows us
to avoid searching for each vpfn individually in the function
vfio_unpin_pages_remote(). This patch batches the vfio_find_vpfn()
calls in function vfio_unpin_pages_remote().

Signed-off-by: Li Zhe 
Link: https://lore.kernel.org/r/20250814064714.56485-4-lizhe.67@bytedance.com
Signed-off-by: Alex Williamson

vfio/type1: optimize vfio_pin_pages_remote()

2025-10-06T17:21:26+00:00

When vfio_pin_pages_remote() is called with a range of addresses that
includes large folios, the function currently performs individual
statistics counting operations for each page. This can lead to significant
performance overheads, especially when dealing with large ranges of pages.
Batch processing of statistical counting operations can effectively enhance
performance.

In addition, the pages obtained through longterm GUP are neither invalid
nor reserved. Therefore, we can reduce the overhead associated with some
calls to function is_invalid_reserved_pfn().

The performance test results for completing the 16G VFIO IOMMU DMA mapping
are as follows.

Base(v6.16):
------- AVERAGE (MADV_HUGEPAGE) --------
VFIO MAP DMA in 0.049 s (328.5 GB/s)
------- AVERAGE (MAP_POPULATE) --------
VFIO MAP DMA in 0.268 s (59.6 GB/s)
------- AVERAGE (HUGETLBFS) --------
VFIO MAP DMA in 0.051 s (310.9 GB/s)

With this patch:
------- AVERAGE (MADV_HUGEPAGE) --------
VFIO MAP DMA in 0.025 s (629.8 GB/s)
------- AVERAGE (MAP_POPULATE) --------
VFIO MAP DMA in 0.253 s (63.1 GB/s)
------- AVERAGE (HUGETLBFS) --------
VFIO MAP DMA in 0.030 s (530.5 GB/s)

For large folio, we achieve an over 40% performance improvement.
For small folios, the performance test results indicate a
slight improvement.

Signed-off-by: Li Zhe 
Co-developed-by: Alex Williamson 
Acked-by: David Hildenbrand 
Tested-by: Eric Farman 
Link: https://lore.kernel.org/r/20250814064714.56485-3-lizhe.67@bytedance.com
Signed-off-by: Alex Williamson

Merge tag 'vfio-v6.18-rc1' of https://github.com/awilliam/linux-vfio

2025-10-04T15:24:54+00:00

Pull VFIO updates from Alex Williamson:

 - Use fdinfo to expose the sysfs path of a device represented by a vfio
   device file (Alex Mastro)

 - Mark vfio-fsl-mc, vfio-amba, and the reset functions for
   vfio-platform for removal as these are either orphaned or believed to
   be unused (Alex Williamson)

 - Add reviewers for vfio-platform to save it from also being marked for
   removal (Mostafa Saleh, Pranjal Shrivastava)

 - VFIO selftests, including basic sanity testing and minimal userspace
   drivers for testing against real hardware. This is also expected to
   provide integration with KVM selftests for KVM-VFIO interfaces (David
   Matlack, Josh Hilke)

 - Fix drivers/cdx and vfio/cdx to build without CONFIG_GENERIC_MSI_IRQ
   (Nipun Gupta)

 - Fix reference leak in hisi_acc (Miaoqian Lin)

 - Use consistent return for unsupported device feature (Alex Mastro)

 - Unwind using the correct memory free callback in vfio/pds (Zilin
   Guan)

 - Use IRQ_DISABLE_LAZY flag to improve handling of pre-PCI2.3 INTx and
   resolve stalled interrupt on ppc64 (Timothy Pearson)

 - Enable GB300 in nvgrace-gpu vfio-pci variant driver (Tushar Dave)

 - Misc:
    - Drop unnecessary ternary conversion in vfio/pci (Xichao Zhao)
    - Grammatical fix in nvgrace-gpu (Morduan Zang)
    - Update Shameer's email address (Shameer Kolothum)
    - Fix document build warning (Alex Williamson)

* tag 'vfio-v6.18-rc1' of https://github.com/awilliam/linux-vfio: (48 commits)
  vfio/nvgrace-gpu: Add GB300 SKU to the devid table
  vfio/pci: Fix INTx handling on legacy non-PCI 2.3 devices
  vfio/pds: replace bitmap_free with vfree
  vfio: return -ENOTTY for unsupported device feature
  hisi_acc_vfio_pci: Fix reference leak in hisi_acc_vfio_debug_init
  vfio/platform: Mark reset drivers for removal
  vfio/amba: Mark for removal
  MAINTAINERS: Add myself as VFIO-platform reviewer
  MAINTAINERS: Add myself as VFIO-platform reviewer
  docs: proc.rst: Fix VFIO Device title formatting
  vfio: selftests: Fix .gitignore for already tracked files
  vfio/cdx: update driver to build without CONFIG_GENERIC_MSI_IRQ
  cdx: don't select CONFIG_GENERIC_MSI_IRQ
  MAINTAINERS: Update Shameer Kolothum's email address
  vfio: selftests: Add a script to help with running VFIO selftests
  vfio: selftests: Make iommufd the default iommu_mode
  vfio: selftests: Add iommufd mode
  vfio: selftests: Add iommufd_compat_type1{,v2} modes
  vfio: selftests: Add vfio_type1v2_mode
  vfio: selftests: Replicate tests across all iommu_modes
  ...

vfio/nvgrace-gpu: Add GB300 SKU to the devid table

2025-09-26T14:38:05+00:00

GB300 is NVIDIA's Grace Blackwell Ultra Superchip.

Add the GB300 SKU device-id to nvgrace_gpu_vfio_pci_table.

Signed-off-by: Tushar Dave 
Reviewed-by: Ankit Agrawal 
Link: https://lore.kernel.org/r/20250925170935.121587-1-tdave@nvidia.com
Signed-off-by: Alex Williamson