Re: [RFC V2 5/8] Revert "vhost-backend: remove vhost_kernel_reset_device()"

[Steven Sistare <steven.sistare@oracle.com>]

On 7/17/2025 2:39 PM, Steve Sistare wrote:
> This reverts commit e6383293eb01928692047e617665a742cca87e23.
> The reset function is needed for CPR.
> 
> Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
> ---
>   hw/virtio/vhost-backend.c | 6 ++++++
>   1 file changed, 6 insertions(+)

This is broken.
Drop this patch 5/8 and replace it with the following.
I still need to refactor this slightly versus patch
   [RFC V2 3/8] vhost: reset vhost devices for cpr
before posting V3.

- Steve

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From: Steve Sistare <steven.sistare@oracle.com>
Date: Mon, 19 Aug 2024 11:16:27 -0700
Subject: [PATCH] vhost: vhost_reset_owner

Define vhost_reset_owner, needed for CPR.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
---
  hw/virtio/vhost-backend.c         | 6 ++++++
  hw/virtio/vhost.c                 | 4 ++--
  include/hw/virtio/vhost-backend.h | 1 +
  3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c
index 833804d..54fc8ee 100644
--- a/hw/virtio/vhost-backend.c
+++ b/hw/virtio/vhost-backend.c
@@ -221,6 +221,11 @@ static int vhost_kernel_set_owner(struct vhost_dev *dev)
      return vhost_kernel_call(dev, VHOST_SET_OWNER, NULL);
  }

+static int vhost_kernel_reset_owner(struct vhost_dev *dev)
+{
+    return vhost_kernel_call(dev, VHOST_RESET_OWNER, NULL);
+}
+
  static int vhost_kernel_get_vq_index(struct vhost_dev *dev, int idx)
  {
      assert(idx >= dev->vq_index && idx < dev->vq_index + dev->nvqs);
@@ -345,6 +350,7 @@ const VhostOps kernel_ops = {
          .vhost_get_features = vhost_kernel_get_features,
          .vhost_set_backend_cap = vhost_kernel_set_backend_cap,
          .vhost_set_owner = vhost_kernel_set_owner,
+        .vhost_reset_owner = vhost_kernel_reset_owner,
          .vhost_get_vq_index = vhost_kernel_get_vq_index,
          .vhost_vsock_set_guest_cid = vhost_kernel_vsock_set_guest_cid,
          .vhost_vsock_set_running = vhost_kernel_vsock_set_running,
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 40d5cd8..72e010f 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -1522,9 +1522,9 @@ static int vhost_cpr_notifier(NotifierWithReturn *notifier,
      }

      if (e->type == MIG_EVENT_PRECOPY_SETUP) {
-        r = dev->vhost_ops->vhost_reset_device(dev);
+        r = dev->vhost_ops->vhost_reset_owner(dev);
          if (r < 0) {
-            VHOST_OPS_DEBUG(r, "vhost_reset_device failed");
+            VHOST_OPS_DEBUG(r, "vhost_reset_owner failed");
          }
      } else if (e->type == MIG_EVENT_PRECOPY_FAILED) {
          r = dev->vhost_ops->vhost_set_owner(dev);
diff --git a/include/hw/virtio/vhost-backend.h b/include/hw/virtio/vhost-backend.h
index d6df209..5b68bfb 100644
--- a/include/hw/virtio/vhost-backend.h
+++ b/include/hw/virtio/vhost-backend.h
@@ -190,6 +190,7 @@ typedef struct VhostOps {
      vhost_get_features_op vhost_get_features;
      vhost_set_backend_cap_op vhost_set_backend_cap;
      vhost_set_owner_op vhost_set_owner;
+    vhost_set_owner_op vhost_reset_owner;
      vhost_reset_device_op vhost_reset_device;
      vhost_get_vq_index_op vhost_get_vq_index;
      vhost_set_vring_enable_op vhost_set_vring_enable;
--
1.8.3.1

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