[RFC PATCH v4 05/20] vhost: Add x-vhost-enable-shadow-vq qmp

["Eugenio Pérez" <eperezma@redhat.com>]

Command to enable shadow virtqueue.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 qapi/net.json          | 23 +++++++++++++++++++++++
 hw/virtio/vhost-vdpa.c |  8 ++++++++
 2 files changed, 31 insertions(+)

diff --git a/qapi/net.json b/qapi/net.json
index 7fab2e7cd8..a2c30fd455 100644
--- a/qapi/net.json
+++ b/qapi/net.json
@@ -79,6 +79,29 @@
 { 'command': 'netdev_del', 'data': {'id': 'str'},
   'allow-preconfig': true }
 
+##
+# @x-vhost-enable-shadow-vq:
+#
+# Use vhost shadow virtqueue.
+#
+# @name: the device name of the VirtIO device
+#
+# @enable: true to use the alternate shadow VQ notifications
+#
+# Returns: Always error, since SVQ is not implemented at the moment.
+#
+# Since: 6.2
+#
+# Example:
+#
+# -> { "execute": "x-vhost-enable-shadow-vq",
+#     "arguments": { "name": "virtio-net", "enable": false } }
+#
+##
+{ 'command': 'x-vhost-enable-shadow-vq',
+  'data': {'name': 'str', 'enable': 'bool'},
+  'if': 'defined(CONFIG_VHOST_KERNEL)' }
+
 ##
 # @NetLegacyNicOptions:
 #
diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
index 4fa414feea..c63e311d7c 100644
--- a/hw/virtio/vhost-vdpa.c
+++ b/hw/virtio/vhost-vdpa.c
@@ -23,6 +23,8 @@
 #include "cpu.h"
 #include "trace.h"
 #include "qemu-common.h"
+#include "qapi/qapi-commands-net.h"
+#include "qapi/error.h"
 
 static bool vhost_vdpa_listener_skipped_section(MemoryRegionSection *section)
 {
@@ -656,6 +658,12 @@ static bool  vhost_vdpa_force_iommu(struct vhost_dev *dev)
     return true;
 }
 
+
+void qmp_x_vhost_enable_shadow_vq(const char *name, bool enable, Error **errp)
+{
+    error_setg(errp, "Shadow virtqueue still not implemented");
+}
+
 const VhostOps vdpa_ops = {
         .backend_type = VHOST_BACKEND_TYPE_VDPA,
         .vhost_backend_init = vhost_vdpa_init,
-- 
2.27.0