Saravanan D 9156758828 pci: clamp sparse mmap holes to physical BAR ...

For VFIO devices with non page aligned MSI-X offsets,
fixup_msix_region() relocates MSI-X table and PBA offsets
into an enlarged virtual BAR by mutating msix.cap in place.
generate_sparse_areas() later reads those relocated offsets
to carve mmap holes, but receives the physical BAR size as
region_size. The relocated offsets exceed the physical BAR
boundary, and the kernel rejects the mmap with EINVAL.

Guard inter_ranges insertion with an offset < region_size
check so relocated entries are skipped. The full physical
BAR is mmapped as a single region. The relocated MSI-X in
the upper half of the virtual BAR remains trapped because
it has no mmap backing.

Linux kernel commit a32295c612c5 ("vfio-pci: Allow mapping
MSIX BAR") allows mmapping the entire BAR including the
MSI-X region when VFIO_REGION_INFO_CAP_MSIX_MAPPABLE is
advertised. The actual security guarantees come from IOMMU
isolation and interrupt remapping, not from filtering
MSI-X table accesses. QEMU follows the same pattern,
mmapping the entire physical BAR when MsixMappable is
present.

Fixes: #7898

Signed-off-by: Saravanan D <saravanand@crusoe.ai>

2026-03-27 10:55:59 +00:00

..

src

pci: clamp sparse mmap holes to physical BAR

2026-03-27 10:55:59 +00:00

Cargo.toml

misc: make MSRV workspace-wide for cloud-hypervisor dependencies

2026-03-13 01:30:25 +00:00