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author | Greg Kurz <gkurz@linux.vnet.ibm.com> | 2015-06-17 15:23:39 +0200 |
---|---|---|
committer | Michael S. Tsirkin <mst@redhat.com> | 2015-06-17 17:12:54 +0200 |
commit | 04b7a1523d65bb5c78832098cf3108a1aadcaf8a (patch) | |
tree | ffcd7a89ade77fd5603e0c3390d18822cd83409f | |
parent | 41d283bdab08868a244b9c19dce507fdf15a8990 (diff) | |
download | hqemu-04b7a1523d65bb5c78832098cf3108a1aadcaf8a.zip hqemu-04b7a1523d65bb5c78832098cf3108a1aadcaf8a.tar.gz |
vhost: set vring endianness for legacy virtio
Legacy virtio is native endian: if the guest and host endianness differ,
we have to tell vhost so it can swap bytes where appropriate. This is
done through a vhost ring ioctl.
Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
-rw-r--r-- | hw/virtio/vhost.c | 50 |
1 files changed, 49 insertions, 1 deletions
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c index 7908255..7ea45b3 100644 --- a/hw/virtio/vhost.c +++ b/hw/virtio/vhost.c @@ -17,9 +17,11 @@ #include "hw/hw.h" #include "qemu/atomic.h" #include "qemu/range.h" +#include "qemu/error-report.h" #include <linux/vhost.h> #include "exec/address-spaces.h" #include "hw/virtio/virtio-bus.h" +#include "hw/virtio/virtio-access.h" #include "migration/migration.h" static struct vhost_log *vhost_log; @@ -686,6 +688,27 @@ static void vhost_log_stop(MemoryListener *listener, /* FIXME: implement */ } +static int vhost_virtqueue_set_vring_endian_legacy(struct vhost_dev *dev, + bool is_big_endian, + int vhost_vq_index) +{ + struct vhost_vring_state s = { + .index = vhost_vq_index, + .num = is_big_endian + }; + + if (!dev->vhost_ops->vhost_call(dev, VHOST_SET_VRING_ENDIAN, &s)) { + return 0; + } + + if (errno == ENOTTY) { + error_report("vhost does not support cross-endian"); + return -ENOSYS; + } + + return -errno; +} + static int vhost_virtqueue_start(struct vhost_dev *dev, struct VirtIODevice *vdev, struct vhost_virtqueue *vq, @@ -716,6 +739,16 @@ static int vhost_virtqueue_start(struct vhost_dev *dev, return -errno; } + if (!virtio_has_feature(vdev, VIRTIO_F_VERSION_1) && + virtio_legacy_is_cross_endian(vdev)) { + r = vhost_virtqueue_set_vring_endian_legacy(dev, + virtio_is_big_endian(vdev), + vhost_vq_index); + if (r) { + return -errno; + } + } + s = l = virtio_queue_get_desc_size(vdev, idx); a = virtio_queue_get_desc_addr(vdev, idx); vq->desc = cpu_physical_memory_map(a, &l, 0); @@ -786,8 +819,9 @@ static void vhost_virtqueue_stop(struct vhost_dev *dev, struct vhost_virtqueue *vq, unsigned idx) { + int vhost_vq_index = idx - dev->vq_index; struct vhost_vring_state state = { - .index = idx - dev->vq_index + .index = vhost_vq_index, }; int r; assert(idx >= dev->vq_index && idx < dev->vq_index + dev->nvqs); @@ -798,6 +832,20 @@ static void vhost_virtqueue_stop(struct vhost_dev *dev, } virtio_queue_set_last_avail_idx(vdev, idx, state.num); virtio_queue_invalidate_signalled_used(vdev, idx); + + /* In the cross-endian case, we need to reset the vring endianness to + * native as legacy devices expect so by default. + */ + if (!virtio_has_feature(vdev, VIRTIO_F_VERSION_1) && + virtio_legacy_is_cross_endian(vdev)) { + r = vhost_virtqueue_set_vring_endian_legacy(dev, + !virtio_is_big_endian(vdev), + vhost_vq_index); + if (r < 0) { + error_report("failed to reset vring endianness"); + } + } + assert (r >= 0); cpu_physical_memory_unmap(vq->ring, virtio_queue_get_ring_size(vdev, idx), 0, virtio_queue_get_ring_size(vdev, idx)); |