Commit Graph

14 Commits

Author SHA1 Message Date
Cornelia Huck b0e5d90ebc dataplane: endianness-aware accesses
The vring.c code currently assumes that guest and host endianness match,
which is not true for a number of cases:

- emulating targets with a different endianness than the host
- bi-endian targets, where the correct endianness depends on the virtio
  device
- upcoming support for the virtio-1 standard mandates little-endian
  accesses even for big-endian targets and hosts

Make sure to use accessors that depend on the virtio device.

Note that dataplane now needs to be built per-target.

Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Fam Zheng <famz@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Tested-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 1422289602-17874-2-git-send-email-cornelia.huck@de.ibm.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2015-02-16 15:07:16 +00:00
Cornelia Huck 91d5c57a2e virtio: fix feature bit checks
Several places check against the feature bit number instead of against
the feature bit. Fix them.

Cc: qemu-stable@nongnu.org
Reported-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2015-01-27 14:46:17 +02:00
Bin Wu a3614c65cf hw/virtio/vring/event_idx: fix the vring_avail_event error
The event idx in virtio is an effective way to reduce the number of
interrupts and exits of the guest. When the guest puts an request
into the virtio ring, it doesn't exit immediately to inform the
backend. Instead, the guest checks the "avail" event idx to determine
the notification.

In virtqueue_pop, when a request is poped, the current avail event
idx should be set to the number of vq->last_avail_idx.

Signed-off-by: Bin Wu <wu.wubin@huawei.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-11-02 13:44:12 +02:00
Fam Zheng 032f8b8158 vring: Better error handling if num is too large
To be more consistent inside this function.

Signed-off-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1410329871-28885-3-git-send-email-famz@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-09-22 11:39:49 +01:00
Stefan Hajnoczi f897bf751f virtio-blk: embed VirtQueueElement in VirtIOBlockReq
The memory allocation between hw/block/virtio-blk.c,
hw/block/dataplane/virtio-blk.c, and hw/virtio/dataplane/vring.c is
messy.  Structs are allocated in different files than they are freed in.
This is risky and makes memory leaks easier.

Embed VirtQueueElement in VirtIOBlockReq to reduce the amount of memory
allocation we need to juggle.  This also makes vring.c and virtio.c
slightly more similar.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-07-14 12:03:20 +02:00
Stefan Hajnoczi abd764250f dataplane: do not free VirtQueueElement in vring_push()
VirtQueueElement is allocated in vring_pop() so it seems to make sense
that vring_push() should free it.  Alas, virtio-blk frees
VirtQueueElement itself in virtio_blk_free_request().

This patch solves a double-free assertion in glib's g_slice_free().

Rename vring_free_element() to vring_unmap_element() since it no longer
frees the VirtQueueElement.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Tested-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-07-14 12:03:20 +02:00
Stefan Hajnoczi 385c04d0b6 dataplane: fix shadowed return value
Propagate the error return value from get_indirect().  This bug was
introduced in commit 4d684832 ("vring: create a common function to parse
descriptors").

Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-01-22 13:48:18 +01:00
Paolo Bonzini 87b7f2f8c8 dataplane: replace hostmem with memory_region_find
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-20 09:11:57 +01:00
Paolo Bonzini 8c1b566fd1 dataplane: change vring API to use VirtQueueElement
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-20 09:11:57 +01:00
Paolo Bonzini 781c117f37 vring: factor common code for error exits
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-20 09:11:57 +01:00
Paolo Bonzini 4d684832e5 vring: create a common function to parse descriptors
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-12-20 09:11:57 +01:00
Stefan Hajnoczi 6793dfd1b6 virtio: clear signalled_used_valid when switching from dataplane
When the dataplane thread stops, its vring.c implementation synchronizes
vring state back to virtio.c so we can continue emulating the virtio
device.

This patch ensures that virtio.c's signalled_used_valid flag is reset so
that we do not suppress guest notifications due to stale signalled_used
values.

Suggested-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2013-08-12 12:19:04 +03:00
Stefan Hajnoczi 9154b02c53 dataplane: sync virtio.c and vring.c virtqueue state
Load the virtio.c state into vring.c when we start dataplane mode and
vice versa when stopping dataplane mode.  This patch makes it possible
to start and stop dataplane any time while the guest is running.

This will eventually allow us to go back to QEMU main loop for
bdrv_drain_all() and live migration.  In the meantime, this patch makes
the dataplane lifecycle more robust but should make no visible
difference.  It may be useful in the virtio-net dataplane effort.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-07-19 12:29:21 +08:00
Paolo Bonzini 6e7907468f hw: move virtio devices to hw/ subdirectories
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2013-04-08 18:13:12 +02:00