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| author | Will Deacon <will.deacon@arm.com> | 2012-10-19 14:03:33 +0100 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2013-01-03 03:32:58 +0000 |
| commit | 1e02c9c8133e41c623596f5b09eb9185a2f69bcc (patch) | |
| tree | dd97aa32898c6d728b927ba091e372ec36f3b196 | |
| parent | 30d395b124c51db66d9f3ba0611cd62021afc392 (diff) | |
| download | kernel_samsung_smdk4412-1e02c9c8133e41c623596f5b09eb9185a2f69bcc.zip kernel_samsung_smdk4412-1e02c9c8133e41c623596f5b09eb9185a2f69bcc.tar.gz kernel_samsung_smdk4412-1e02c9c8133e41c623596f5b09eb9185a2f69bcc.tar.bz2 | |
virtio: force vring descriptors to be allocated from lowmem
commit b92b1b89a33c172c075edccf6afb0edc41d851fd upstream.
Virtio devices may attempt to add descriptors to a virtqueue from atomic
context using GFP_ATOMIC allocation. This is problematic because such
allocations can fall outside of the lowmem mapping, causing virt_to_phys
to report bogus physical addresses which are subsequently passed to
userspace via the buffers for the virtual device.
This patch masks out __GFP_HIGH and __GFP_HIGHMEM from the requested
flags when allocating descriptors for a virtqueue. If an atomic
allocation is requested and later fails, we will return -ENOSPC which
will be handled by the driver.
Cc: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -rw-r--r-- | drivers/virtio/virtio_ring.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index c7a2c20..dc2eed1 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -121,6 +121,13 @@ static int vring_add_indirect(struct vring_virtqueue *vq, unsigned head; int i; + /* + * We require lowmem mappings for the descriptors because + * otherwise virt_to_phys will give us bogus addresses in the + * virtqueue. + */ + gfp &= ~(__GFP_HIGHMEM | __GFP_HIGH); + desc = kmalloc((out + in) * sizeof(struct vring_desc), gfp); if (!desc) return -ENOMEM; |