If riov and wiov are both defined and they point to different
objects, only riov is initialized. If the wiov is not initialized
by the caller, the function fails returning -EINVAL and printing
"Readable desc 0x... after writable" error message.
This issue happens when descriptors have both readable and writable
buffers (eg. virtio-blk devices has virtio_blk_outhdr in the readable
buffer and status as last byte of writable buffer) and we call
__vringh_iov() to get both type of buffers in two different iovecs.
Let's replace the 'else if' clause with 'if' to initialize both
riov and wiov if they are not NULL.
As checkpatch pointed out, we also avoid crashing the kernel
when riov and wiov are both NULL, replacing BUG() with WARN_ON()
and returning -EINVAL.
Fixes: f87d0fbb57 ("vringh: host-side implementation of virtio rings.")
Cc: stable@vger.kernel.org
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Link: https://lore.kernel.org/r/20201008204256.162292-1-sgarzare@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
The ring element addresses are passed between components with different
alignments assumptions. Thus, if guest/userspace selects a pointer and
host then gets and dereferences it, we might need to decrease the
compiler-selected alignment to prevent compiler on the host from
assuming pointer is aligned.
This actually triggers on ARM with -mabi=apcs-gnu - which is a
deprecated configuration, but it seems safer to handle this
generally.
Note that userspace that allocates the memory is actually OK and does
not need to be fixed, but userspace that gets it from guest or another
process does need to be fixed. The later doesn't generally talk to the
kernel so while it might be buggy it's not talking to the kernel in the
buggy way - it's just using the header in the buggy way - so fixing
header and asking userspace to recompile is the best we can do.
I verified that the produced kernel binary on x86 is exactly identical
before and after the change.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Allow building vringh without IOTLB (that's the case for userspace
builds, will be useful for CAIF/VOD down the road too).
Update for API tweaks.
Don't include vringh with userspace builds.
Cc: Jason Wang <jasowang@redhat.com>
Cc: Eugenio Pérez <eperezma@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
This patch implements the third memory accessor for vringh besides
current kernel and userspace accessors. This idea is to allow vringh
to do the address translation through an IOTLB which is implemented
via vhost_map interval tree. Users should setup and IOVA to PA mapping
in this IOTLB.
This allows us to:
- Use vringh to access virtqueues with vIOMMU
- Use vringh to implement software virtqueues for vDPA devices
Signed-off-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20200326140125.19794-5-jasowang@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
We want to copy from iov to buf, so the direction was wrong.
Note: no real user for the helper, but it will be used by future
features.
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Add SPDX license identifiers to all files which:
- Have no license information of any form
- Have MODULE_LICENCE("GPL*") inside which was used in the initial
scan/conversion to ignore the file
These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:
GPL-2.0-only
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Despite living under drivers/ vringh.c is also used as part of the userspace
virtio tools. Before we can kill off the ACCESS_ONCE()definition in the tools,
we must convert vringh.c to use {READ,WRITE}_ONCE().
This patch does so, along with the required include of <linux/compiler.h> for
the relevant definitions. The userspace tools provide their own definitions in
their own <linux/compiler.h>.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: virtualization@lists.linux-foundation.org
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Jason Wang <jasowang@redhat.com>
When switching everything over to virtio 1.0 memory access APIs,
I missed converting vringh.
Fortunately, it's straight-forward.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Getting use of virtio rings correct is tricky, and a recent patch saw
an implementation of in-kernel rings (as separate from userspace).
This abstracts the business of dealing with the virtio ring layout
from the access (userspace or direct); to do this, we use function
pointers, which gcc inlines correctly.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Stefano Garzarella