vhost: fix caching attributes of MMIO regions by setting them explicitly

Explicitly set non-cached caching attributes for MMIO regions.
Default write-back mode can cause CPU to cache device memory,
causing invalid reads and unpredictable behavior.

Invalid read and write issues were observed on ARM64 when mapping the
notification area to userspace via mmap.

Signed-off-by: Kommula Shiva Shankar <kshankar@marvell.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-Id: <20260102065703.656255-1-kshankar@marvell.com>
This commit is contained in:
Kommula Shiva Shankar
2026-01-02 12:27:03 +05:30
committed by Michael S. Tsirkin
parent 503ef41e88
commit 5145b27730

View File

@@ -1529,6 +1529,7 @@ static int vhost_vdpa_mmap(struct file *file, struct vm_area_struct *vma)
if (vma->vm_end - vma->vm_start != notify.size)
return -ENOTSUPP;
vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
vm_flags_set(vma, VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP);
vma->vm_ops = &vhost_vdpa_vm_ops;
return 0;