在 2023/2/8 17:42, Eugenio Pérez 写道:
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 Pérez <eperezma@xxxxxxxxxx>
---
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) {
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