[PATCH] vdpa: Avoid reset when stop device

From: 08005325@163.com
To: qemu-devel@nongnu.org
Cc: jasowang@redhat.com, Michael Qiu <qiudayu@archeros.com>, lulu@redhat.com
Subject: [PATCH] vdpa: Avoid reset when stop device
Date: Wed, 23 Mar 2022 04:42:46 -0400	[thread overview]
Message-ID: <1648024966-5170-1-git-send-email-08005325@163.com> (raw)

From: Michael Qiu <qiudayu@archeros.com>

Currently, when VM poweroff, it will trigger vdpa
device(such as mlx bluefield2 VF) reset twice, this leads
to below issue:

vhost VQ 2 ring restore failed: -22: Invalid argument (22)

This because in vhost_dev_stop(), qemu tries to stop the device,
then stop the queue: vhost_virtqueue_stop().
In vhost_dev_stop(), it resets the device, which clear some flags
in low level driver, and the driver finds
that the VQ is invalied, this is the root cause.

Actually, device reset will be called within func release()

To solve the issue, vdpa should set vring unready, and
remove reset ops in device stop: vhost_dev_start(hdev, false).

Signed-off-by: Michael Qiu<qiudayu@archeros.com>
---
 hw/virtio/vhost-vdpa.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index c5ed7a3..d858b4f 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -719,14 +719,14 @@ static int vhost_vdpa_get_vq_index(struct vhost_dev *dev, int idx)
     return idx;
 }
 
-static int vhost_vdpa_set_vring_ready(struct vhost_dev *dev)
+static int vhost_vdpa_set_vring_ready(struct vhost_dev *dev, unsigned int ready)
 {
     int i;
     trace_vhost_vdpa_set_vring_ready(dev);
     for (i = 0; i < dev->nvqs; ++i) {
         struct vhost_vring_state state = {
             .index = dev->vq_index + i,
-            .num = 1,
+            .num = ready,
         };
         vhost_vdpa_call(dev, VHOST_VDPA_SET_VRING_ENABLE, &state);
     }
@@ -1088,8 +1088,9 @@ static int vhost_vdpa_dev_start(struct vhost_dev *dev, bool started)
         if (unlikely(!ok)) {
             return -1;
         }
-        vhost_vdpa_set_vring_ready(dev);
+        vhost_vdpa_set_vring_ready(dev, 1);
     } else {
+        vhost_vdpa_set_vring_ready(dev, 0);
         ok = vhost_vdpa_svqs_stop(dev);
         if (unlikely(!ok)) {
             return -1;
@@ -1105,7 +1106,6 @@ static int vhost_vdpa_dev_start(struct vhost_dev *dev, bool 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);
-- 
1.8.3.1


