Commit 3a3e0fad authored by Jason Wang's avatar Jason Wang Committed by Michael S. Tsirkin
Browse files

vhost-vdpa: fix vm_flags for virtqueue doorbell mapping 



The virtqueue doorbell is usually implemented via registeres but we
don't provide the necessary vma->flags like VM_PFNMAP. This may cause
several issues e.g when userspace tries to map the doorbell via vhost
IOTLB, kernel may panic due to the page is not backed by page
structure. This patch fixes this by setting the necessary
vm_flags. With this patch, try to map doorbell via IOTLB will fail
with bad address.

Cc: stable@vger.kernel.org
Fixes: ddd89d0a ("vhost_vdpa: support doorbell mapping via mmap")
Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20210413091557.29008-1-jasowang@redhat.com


Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 526cb858

drivers/vhost/vdpa.c

+1 −0
Original line number Diff line number Diff line
@@ -993,6 +993,7 @@ 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_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;

	vma->vm_ops = &vhost_vdpa_vm_ops;

	return 0;

}