|
From: | Zhu, Lingshan |
Subject: | Re: [PATCH] vdpa: dont check vhost_vdpa->suspended when unsupported |
Date: | Fri, 9 Jun 2023 16:49:00 +0800 |
User-agent: | Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Firefox/102.0 Thunderbird/102.12.0 |
On 6/9/2023 11:13 AM, Jason Wang wrote:
On Wed, Jun 7, 2023 at 11:37 PM Eugenio Perez Martin <eperezma@redhat.com> wrote:On Wed, Jun 7, 2023 at 11:09 AM Zhu Lingshan <lingshan.zhu@intel.com> wrote:When read the state of a virtqueue, vhost_vdpa need to check whether the device is suspended. This commit verifies whether VHOST_BACKEND_F_SUSPEND is negotiated when checking vhost_vdpa->suspended.I'll add: Otherwise, qemu prints XXX error message. On second thought, not returning an error prevents the caller (vhost.c:vhost_virtqueue_stop) from recovering used idx from the guest. I'm not sure about the right fix for this, should we call virtio_queue_restore_last_avail_idx here?It should be the duty of the caller: E.g in vhost_virtqueue_stop() we had: => r = dev->vhost_ops->vhost_get_vring_base(dev, &state); if (r < 0) { VHOST_OPS_DEBUG(r, "vhost VQ %u ring restore failed: %d", idx, r); /* Connection to the backend is broken, so let's sync internal * last avail idx to the device used idx. */ virtio_queue_restore_last_avail_idx(vdev, idx); } else { virtio_queue_set_last_avail_idx(vdev, idx, state.num);
I agree call virtio_queue_restore_last_avail_idx here in the caller is better. However I found this debug message is confused: _get_vring_base() read the queue state, it does not restore anything,and if failed to read the queue state, it invokes virtio_queue_restore_last_avail_idx()
to recover, still works, handled the problem internally. So how about we remove this debug message or change it to: restore last_avail_idx of vhost vq N from vring used_idx. Thanks
ThanskCommunicate that the backend cannot suspend so vhost.c can print a better error message? Thanks!Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com> --- hw/virtio/vhost-vdpa.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c index b3094e8a8b..ae176c06dd 100644 --- a/hw/virtio/vhost-vdpa.c +++ b/hw/virtio/vhost-vdpa.c @@ -1397,7 +1397,7 @@ static int vhost_vdpa_get_vring_base(struct vhost_dev *dev, return 0; } - if (!v->suspended) { + if ((dev->backend_cap & BIT_ULL(VHOST_BACKEND_F_SUSPEND)) && (!v->suspended)) { /* * Cannot trust in value returned by device, let vhost recover used * idx from guest. -- 2.39.1
[Prev in Thread] | Current Thread | [Next in Thread] |