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vhost-vdpa: fix vm_flags for virtqueue doorbell mapping

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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: ddd89d0a05 ("vhost_vdpa: support doorbell mapping via mmap")
Signed-off-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20210413091557.29008-1-jasowang@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Jason Wang 2021-04-13 17:15:57 +08:00 committed by Michael S. Tsirkin
parent 526cb8580b
commit 3a3e0fad16
1 changed files with 1 additions and 0 deletions
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1
drivers/vhost/vdpa.c
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@ -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) if (vma->vm_end - vma->vm_start != notify.size)
return -ENOTSUPP; return -ENOTSUPP;
vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
vma->vm_ops = &vhost_vdpa_vm_ops; vma->vm_ops = &vhost_vdpa_vm_ops;
return 0; return 0;
} }