On Tue, 2 Dec 2014 15:54:44 +0100
Cornelia Huck <cornelia.huck@xxxxxxxxxx> wrote:
> On Tue, 2 Dec 2014 16:46:28 +0200
> "Michael S. Tsirkin" <mst@xxxxxxxxxx> wrote:
> > pa == -1ULL tricks look quite ugly.
> > Can't we set desc/avail/used unconditionally, and drop
> > the pa value?
>
> And have virtio_queue_get_addr() return desc? Let me see if I can come
> up with a patch.
I came up with the following (untested) patch, which should hopefully
suit mmio as well. I haven't cared about migration yet.
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 8f69ffa..ac3c615 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -69,7 +69,6 @@ typedef struct VRing
struct VirtQueue
{
VRing vring;
- hwaddr pa;
uint16_t last_avail_idx;
/* Last used index value we have signalled on */
uint16_t signalled_used;
@@ -92,12 +91,13 @@ struct VirtQueue
};
/* virt queue functions */
-static void virtqueue_init(VirtQueue *vq)
+static void virtqueue_update_rings(VirtQueue *vq)
{
- hwaddr pa = vq->pa;
-
- vq->vring.desc = pa;
- vq->vring.avail = pa + vq->vring.num * sizeof(VRingDesc);
+ if (!vq->vring.desc) {
+ /* not yet setup -> nothing to do */
+ return;
+ }
+ vq->vring.avail = vq->vring.desc + vq->vring.num * sizeof(VRingDesc);
vq->vring.used = vring_align(vq->vring.avail +
offsetof(VRingAvail, ring[vq->vring.num]),
vq->vring.align);
@@ -605,7 +605,6 @@ void virtio_reset(void *opaque)
vdev->vq[i].vring.avail = 0;
vdev->vq[i].vring.used = 0;
vdev->vq[i].last_avail_idx = 0;
- vdev->vq[i].pa = 0;
vdev->vq[i].vector = VIRTIO_NO_VECTOR;
vdev->vq[i].signalled_used = 0;
vdev->vq[i].signalled_used_valid = false;
@@ -708,17 +707,34 @@ void virtio_config_writel(VirtIODevice *vdev, uint32_t addr, uint32_t data)
void virtio_queue_set_addr(VirtIODevice *vdev, int n, hwaddr addr)
{
- vdev->vq[n].pa = addr;
- virtqueue_init(&vdev->vq[n]);
+ vdev->vq[n].vring.desc = addr;
+ virtqueue_update_rings(&vdev->vq[n]);
}
hwaddr virtio_queue_get_addr(VirtIODevice *vdev, int n)
{
- return vdev->vq[n].pa;
+ return vdev->vq[n].vring.desc;
+}
+
+void virtio_queue_set_rings(VirtIODevice *vdev, int n, hwaddr desc,
+ hwaddr avail, hwaddr used)
+{
+ vdev->vq[n].vring.desc = desc;
+ vdev->vq[n].vring.avail = avail;
+ vdev->vq[n].vring.used = used;
}
void virtio_queue_set_num(VirtIODevice *vdev, int n, int num)
{
+ /*
+ * For virtio-1 devices, the number of buffers may only be
+ * updated if the ring addresses have not yet been set up.
+ */
+ if (virtio_has_feature(vdev, VIRTIO_F_VERSION_1) &&
+ vdev->vq[n].vring.desc) {
+ error_report("tried to modify buffer num for virtio-1 device");
+ return;
+ }
/* Don't allow guest to flip queue between existent and
* nonexistent states, or to set it to an invalid size.
*/
@@ -728,7 +744,7 @@ void virtio_queue_set_num(VirtIODevice *vdev, int n, int num)
return;
}
vdev->vq[n].vring.num = num;
- virtqueue_init(&vdev->vq[n]);
+ virtqueue_update_rings(&vdev->vq[n]);
}
int virtio_queue_get_num(VirtIODevice *vdev, int n)
@@ -748,6 +764,11 @@ void virtio_queue_set_align(VirtIODevice *vdev, int n, int align)
BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
+ /* virtio-1 compliant devices cannot change the aligment */
+ if (virtio_has_feature(vdev, VIRTIO_F_VERSION_1)) {
+ error_report("tried to modify queue alignment for virtio-1 device");
+ return;
+ }
/* Check that the transport told us it was going to do this
* (so a buggy transport will immediately assert rather than
* silently failing to migrate this state)
@@ -755,7 +776,7 @@ void virtio_queue_set_align(VirtIODevice *vdev, int n, int align)
assert(k->has_variable_vring_alignment);
vdev->vq[n].vring.align = align;
- virtqueue_init(&vdev->vq[n]);
+ virtqueue_update_rings(&vdev->vq[n]);
}
void virtio_queue_notify_vq(VirtQueue *vq)
@@ -949,7 +970,8 @@ void virtio_save(VirtIODevice *vdev, QEMUFile *f)
if (k->has_variable_vring_alignment) {
qemu_put_be32(f, vdev->vq[i].vring.align);
}
- qemu_put_be64(f, vdev->vq[i].pa);
+ /* XXX virtio-1 devices */
+ qemu_put_be64(f, vdev->vq[i].vring.desc);
qemu_put_be16s(f, &vdev->vq[i].last_avail_idx);
if (k->save_queue) {
k->save_queue(qbus->parent, i, f);
@@ -1044,13 +1066,14 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id)
if (k->has_variable_vring_alignment) {
vdev->vq[i].vring.align = qemu_get_be32(f);
}
- vdev->vq[i].pa = qemu_get_be64(f);
+ vdev->vq[i].vring.desc = qemu_get_be64(f);
qemu_get_be16s(f, &vdev->vq[i].last_avail_idx);
vdev->vq[i].signalled_used_valid = false;
vdev->vq[i].notification = true;
- if (vdev->vq[i].pa) {
- virtqueue_init(&vdev->vq[i]);
+ if (vdev->vq[i].vring.desc) {
+ /* XXX virtio-1 devices */
+ virtqueue_update_rings(&vdev->vq[i]);
} else if (vdev->vq[i].last_avail_idx) {
error_report("VQ %d address 0x0 "
"inconsistent with Host index 0x%x",
@@ -1084,7 +1107,7 @@ int virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id)
}
for (i = 0; i < num; i++) {
- if (vdev->vq[i].pa) {
+ if (vdev->vq[i].vring.desc) {
uint16_t nheads;
nheads = vring_avail_idx(&vdev->vq[i]) - vdev->vq[i].last_avail_idx;
/* Check it isn't doing strange things with descriptor numbers. */
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index 68c40db..80ee313 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -224,6 +224,8 @@ void virtio_queue_set_addr(VirtIODevice *vdev, int n, hwaddr addr);
hwaddr virtio_queue_get_addr(VirtIODevice *vdev, int n);
void virtio_queue_set_num(VirtIODevice *vdev, int n, int num);
int virtio_queue_get_num(VirtIODevice *vdev, int n);
+void virtio_queue_set_rings(VirtIODevice *vdev, int n, hwaddr desc,
+ hwaddr avail, hwaddr used);
void virtio_queue_set_align(VirtIODevice *vdev, int n, int align);
void virtio_queue_notify(VirtIODevice *vdev, int n);
uint16_t virtio_queue_vector(VirtIODevice *vdev, int n);
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