CVQ can be shadowed two ways:
- Device has x-svq=on parameter (current way)
- The device can isolate CVQ in its own vq group

QEMU needs to check for the second condition dynamically, because CVQ
index is not known at initialization time. Since this is dynamic, the
CVQ isolation could vary with different conditions, making it possible
to go from "not isolated group" to "isolated".

Saving the cmdline parameter in an extra field so we never disable CVQ
SVQ in case the device was started with cmdline.

Signed-off-by: Eugenio Pérez <eperezma@redhat.com>
---
 net/vhost-vdpa.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
index 89b01fcaec..5185ac7042 100644
--- a/net/vhost-vdpa.c
+++ b/net/vhost-vdpa.c
@@ -38,6 +38,8 @@ typedef struct VhostVDPAState {
     void *cvq_cmd_out_buffer;
     virtio_net_ctrl_ack *status;
 
+    /* The device always have SVQ enabled */
+    bool always_svq;
     bool started;
 } VhostVDPAState;
 
@@ -566,6 +568,7 @@ static NetClientState *net_vhost_vdpa_init(NetClientState *peer,
 
     s->vhost_vdpa.device_fd = vdpa_device_fd;
     s->vhost_vdpa.index = queue_pair_index;
+    s->always_svq = svq;
     s->vhost_vdpa.shadow_vqs_enabled = svq;
     s->vhost_vdpa.iova_tree = iova_tree;
     if (!is_datapath) {
-- 
2.31.1

在 2022/11/16 23:05, Eugenio Pérez 写道:
> CVQ can be shadowed two ways:
> - Device has x-svq=on parameter (current way)
> - The device can isolate CVQ in its own vq group
>
> QEMU needs to check for the second condition dynamically, because CVQ
> index is not known at initialization time. Since this is dynamic, the
> CVQ isolation could vary with different conditions, making it possible
> to go from "not isolated group" to "isolated".
>
> Saving the cmdline parameter in an extra field so we never disable CVQ
> SVQ in case the device was started with cmdline.
>
> Signed-off-by: Eugenio Pérez <eperezma@redhat.com>


Acked-by: Jason Wang <jasowang@redhat.com>

Thanks


> ---
>   net/vhost-vdpa.c | 3 +++
>   1 file changed, 3 insertions(+)
>
> diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
> index 89b01fcaec..5185ac7042 100644
> --- a/net/vhost-vdpa.c
> +++ b/net/vhost-vdpa.c
> @@ -38,6 +38,8 @@ typedef struct VhostVDPAState {
>       void *cvq_cmd_out_buffer;
>       virtio_net_ctrl_ack *status;
>   
> +    /* The device always have SVQ enabled */
> +    bool always_svq;
>       bool started;
>   } VhostVDPAState;
>   
> @@ -566,6 +568,7 @@ static NetClientState *net_vhost_vdpa_init(NetClientState *peer,
>   
>       s->vhost_vdpa.device_fd = vdpa_device_fd;
>       s->vhost_vdpa.index = queue_pair_index;
> +    s->always_svq = svq;
>       s->vhost_vdpa.shadow_vqs_enabled = svq;
>       s->vhost_vdpa.iova_tree = iova_tree;
>       if (!is_datapath) {