Saravanan D 23a980cd54 pci: expand sub-page VFIO BAR mmap to page size ...

On aarch64 with 64K host pages, VFIO passthrough of devices with
sub-page BARs (e.g. 16K NVMe BAR0) crashes with EINVAL from
KVM_SET_USER_MEMORY_REGION, which requires memory_size to be a
multiple of the host page size.

Expand the mmap to page size instead of rejecting it, matching
QEMU's approach. The kernel's vfio_pci_probe_mmaps() already
verifies that sub-page BARs are page-aligned and reserves the
remainder of the page, so expansion is safe at offset 0. Reject
sub-page sparse areas at non-zero offsets where this guarantee
does not apply.

The expanded mmap region will not overlap with the relocated MSI-X
trap region because fixup_msix_region() ensures MSI-X relocation
at >= page_size offset.

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

2026-04-12 11:12:48 +00:00

..

src

pci: expand sub-page VFIO BAR mmap to page size

2026-04-12 11:12:48 +00:00

Cargo.toml

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

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