From 74c2f378bdf278a03c02ae48948b00b4431a3fd6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Eugenio=20P=C3=A9rez?= <eperezma@redhat.com>
Date: Fri, 2 Jun 2023 16:38:52 +0200
Subject: [PATCH 6/9] vdpa: do not block migration if device has cvq and
 x-svq=on
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RH-Author: Eugenio Pérez <eperezma@redhat.com>
RH-MergeRequest: 190: vdpa: do not block migration if device has cvq and x-svq=on
RH-Jira: RHEL-573
RH-Acked-by: Jason Wang <jasowang@redhat.com>
RH-Acked-by: Laurent Vivier <lvivier@redhat.com>
RH-Commit: [1/1] b0e2ec3c9e5c17252cf6a043fe1374ddc3c37de7 (eperezmartin/qemu-kvm)

It was a mistake to forbid in all cases, as SVQ is already able to send
all the CVQ messages before start forwarding data vqs.  It actually
caused a regression, making impossible to migrate device previously
migratable.

Fixes: 36e4647247f2 ("vdpa: add vhost_vdpa_net_valid_svq_features")
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
Message-Id: <20230602143854.1879091-2-eperezma@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
(cherry picked from commit 8bc0049eadafb984d305c847cedff550b58e5fc0)
Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 net/vhost-vdpa.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index 8c8900f0f4..1ae839da34 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -844,13 +844,16 @@ static NetClientState *net_vhost_vdpa_init(NetClientState *peer,
         s->vhost_vdpa.shadow_vq_ops_opaque = s;
 
         /*
-         * TODO: We cannot migrate devices with CVQ as there is no way to set
-         * the device state (MAC, MQ, etc) before starting the datapath.
+         * TODO: We cannot migrate devices with CVQ and no x-svq enabled as
+         * there is no way to set the device state (MAC, MQ, etc) before
+         * starting the datapath.
          *
          * Migration blocker ownership now belongs to s->vhost_vdpa.
          */
-        error_setg(&s->vhost_vdpa.migration_blocker,
-                   "net vdpa cannot migrate with CVQ feature");
+        if (!svq) {
+            error_setg(&s->vhost_vdpa.migration_blocker,
+                       "net vdpa cannot migrate with CVQ feature");
+        }
     }
     ret = vhost_vdpa_add(nc, (void *)&s->vhost_vdpa, queue_pair_index, nvqs);
     if (ret) {
-- 
2.39.3