Jason Wang
2023-Feb-21 05:36 UTC
[PATCH v2 04/13] vdpa: move vhost reset after get vring base
? 2023/2/8 17:42, Eugenio P?rez ??:> The function vhost.c:vhost_dev_stop calls vhost operation > vhost_dev_start(false). In the case of vdpa it totally reset and wipes > the device, making the fetching of the vring base (virtqueue state) totally > useless. > > The kernel backend does not use vhost_dev_start vhost op callback, but > vhost-user do. A patch to make vhost_user_dev_start more similar to vdpa > is desirable, but it can be added on top. > > Signed-off-by: Eugenio P?rez <eperezma at redhat.com> > --- > include/hw/virtio/vhost-backend.h | 4 ++++ > hw/virtio/vhost-vdpa.c | 22 ++++++++++++++++------ > hw/virtio/vhost.c | 3 +++ > 3 files changed, 23 insertions(+), 6 deletions(-) > > diff --git a/include/hw/virtio/vhost-backend.h b/include/hw/virtio/vhost-backend.h > index c5ab49051e..ec3fbae58d 100644 > --- a/include/hw/virtio/vhost-backend.h > +++ b/include/hw/virtio/vhost-backend.h > @@ -130,6 +130,9 @@ typedef bool (*vhost_force_iommu_op)(struct vhost_dev *dev); > > typedef int (*vhost_set_config_call_op)(struct vhost_dev *dev, > int fd); > + > +typedef void (*vhost_reset_status_op)(struct vhost_dev *dev); > + > typedef struct VhostOps { > VhostBackendType backend_type; > vhost_backend_init vhost_backend_init; > @@ -177,6 +180,7 @@ typedef struct VhostOps { > vhost_get_device_id_op vhost_get_device_id; > vhost_force_iommu_op vhost_force_iommu; > vhost_set_config_call_op vhost_set_config_call; > + vhost_reset_status_op vhost_reset_status; > } VhostOps; > > int vhost_backend_update_device_iotlb(struct vhost_dev *dev, > diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c > index cbbe92ffe8..26e38a6aab 100644 > --- a/hw/virtio/vhost-vdpa.c > +++ b/hw/virtio/vhost-vdpa.c > @@ -1152,14 +1152,23 @@ static int vhost_vdpa_dev_start(struct vhost_dev *dev, bool started) > if (started) { > memory_listener_register(&v->listener, &address_space_memory); > return vhost_vdpa_add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK); > - } else { > - vhost_vdpa_reset_device(dev); > - vhost_vdpa_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE | > - VIRTIO_CONFIG_S_DRIVER); > - memory_listener_unregister(&v->listener); > + } > > - return 0; > + return 0; > +} > + > +static void vhost_vdpa_reset_status(struct vhost_dev *dev) > +{ > + struct vhost_vdpa *v = dev->opaque; > + > + if (dev->vq_index + dev->nvqs != dev->vq_index_end) { > + return; > } > + > + vhost_vdpa_reset_device(dev); > + vhost_vdpa_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE | > + VIRTIO_CONFIG_S_DRIVER); > + memory_listener_unregister(&v->listener); > } > > static int vhost_vdpa_set_log_base(struct vhost_dev *dev, uint64_t base, > @@ -1346,4 +1355,5 @@ const VhostOps vdpa_ops = { > .vhost_vq_get_addr = vhost_vdpa_vq_get_addr, > .vhost_force_iommu = vhost_vdpa_force_iommu, > .vhost_set_config_call = vhost_vdpa_set_config_call, > + .vhost_reset_status = vhost_vdpa_reset_status, > }; > diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c > index eb8c4c378c..a266396576 100644 > --- a/hw/virtio/vhost.c > +++ b/hw/virtio/vhost.c > @@ -2049,6 +2049,9 @@ void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev, bool vrings) > hdev->vqs + i, > hdev->vq_index + i); > } > + if (hdev->vhost_ops->vhost_reset_status) { > + hdev->vhost_ops->vhost_reset_status(hdev); > + }This looks racy, if we don't suspend/reset the device, device can move last_avail_idx even after get_vring_base()? Instead of doing things like this, should we fallback to virtio_queue_restore_last_avail_idx() in this case? Thanks> > if (vhost_dev_has_iommu(hdev)) { > if (hdev->vhost_ops->vhost_set_iotlb_callback) {