Re: [RFC v1 4/4] vhost: introduce vhost_set_vring_ready method

[Jason Wang <jasowang@redhat.com>]

On 2020/4/20 下午5:32, Cindy Lu wrote:
> From: Jason Wang <jasowang@redhat.com>
>
> Vhost-vdpa introduces VHOST_VDPA_SET_VRING_ENABLE which complies the
> semantic of queue_enable defined in virtio spec. This method can be
> used for preventing device from executing request for a specific
> virtqueue. This patch introduces the vhost_ops for this.
>
> Note that, we've already had vhost_set_vring_enable which has different
> semantic which allows to enable or disable a specific virtqueue for
> some kinds of vhost backends. E.g vhost-user use this to changes the
> number of active queue pairs.


This patch seems to mix fours things, please use dedicated patches for:

1) introduce queue_enabled method for virtio-bus
2) implement queue_enabled for virtio-pci
3) introduce vhost_set_vring_ready method for vhost ops
4) implement vhost_set_vring_ready for vdpa (need to be squashed into 
the patch of vhost-vdpa).

Thanks


>
> Author: Jason Wang <jasowang@redhat.com>
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
>   hw/net/vhost_net-stub.c           |  5 +++++
>   hw/net/vhost_net.c                | 16 ++++++++++++++++
>   hw/virtio/vhost-vdpa.c            |  9 +++------
>   hw/virtio/virtio-pci.c            | 13 +++++++++++++
>   hw/virtio/virtio.c                |  6 ++++++
>   include/hw/virtio/vhost-backend.h |  2 ++
>   include/hw/virtio/virtio-bus.h    |  4 ++++
>   include/net/vhost_net.h           |  1 +
>   8 files changed, 50 insertions(+), 6 deletions(-)
>
> diff --git a/hw/net/vhost_net-stub.c b/hw/net/vhost_net-stub.c
> index aac0e98228..f5ef1e3055 100644
> --- a/hw/net/vhost_net-stub.c
> +++ b/hw/net/vhost_net-stub.c
> @@ -86,6 +86,11 @@ int vhost_set_vring_enable(NetClientState *nc, int enable)
>       return 0;
>   }
>   
> +int vhost_set_vring_ready(NetClientState *nc)
> +{
> +    return 0;
> +}
> +
>   int vhost_net_set_mtu(struct vhost_net *net, uint16_t mtu)
>   {
>       return 0;
> diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
> index 0d13fda2fc..463e333531 100644
> --- a/hw/net/vhost_net.c
> +++ b/hw/net/vhost_net.c
> @@ -380,6 +380,10 @@ int vhost_net_start(VirtIODevice *dev, NetClientState *ncs,
>                   goto err_start;
>               }
>           }
> +
> +        if (virtio_queue_enabled(dev, i)) {
> +            vhost_set_vring_ready(peer);
> +        }
>       }
>   
>       return 0;
> @@ -487,6 +491,18 @@ int vhost_set_vring_enable(NetClientState *nc, int enable)
>       return 0;
>   }
>   
> +int vhost_set_vring_ready(NetClientState *nc)
> +{
> +    VHostNetState *net = get_vhost_net(nc);
> +    const VhostOps *vhost_ops = net->dev.vhost_ops;
> +
> +    if (vhost_ops && vhost_ops->vhost_set_vring_ready) {
> +        return vhost_ops->vhost_set_vring_ready(&net->dev);
> +    }
> +
> +    return 0;
> +}
> +
>   int vhost_net_set_mtu(struct vhost_net *net, uint16_t mtu)
>   {
>       const VhostOps *vhost_ops = net->dev.vhost_ops;
> diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c
> index 213b327600..49224ef9f8 100644
> --- a/hw/virtio/vhost-vdpa.c
> +++ b/hw/virtio/vhost-vdpa.c
> @@ -325,18 +325,15 @@ static int vhost_vdpa_get_vq_index(struct vhost_dev *dev, int idx)
>       return idx - dev->vq_index;
>   }
>   
> -static int vhost_vdpa_set_vring_enable(struct vhost_dev *dev, int enable)
> +static int vhost_vdpa_set_vring_ready(struct vhost_dev *dev)
>   {
>       int i;
>   
>       for (i = 0; i < dev->nvqs; ++i) {
>           struct vhost_vring_state state = {
>               .index = dev->vq_index + i,
> -            .num   = enable,
> +            .num = 1,
>           };
> -
> -        state.num = 1;
> -
>           vhost_vdpa_call(dev, VHOST_VDPA_SET_VRING_ENABLE, &state);
>       }
>   
> @@ -368,7 +365,7 @@ const VhostOps vdpa_ops = {
>           .vhost_set_owner = vhost_vdpa_set_owner,
>           .vhost_reset_device = vhost_vdpa_reset_device,
>           .vhost_get_vq_index = vhost_vdpa_get_vq_index,
> -        .vhost_set_vring_enable = vhost_vdpa_set_vring_enable,
> +        .vhost_set_vring_ready = vhost_vdpa_set_vring_ready,
>           .vhost_requires_shm_log = NULL,
>           .vhost_migration_done = NULL,
>           .vhost_backend_can_merge = NULL,
> diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
> index c6b47a9c73..4aaf5d953e 100644
> --- a/hw/virtio/virtio-pci.c
> +++ b/hw/virtio/virtio-pci.c
> @@ -1103,6 +1103,18 @@ static AddressSpace *virtio_pci_get_dma_as(DeviceState *d)
>       return pci_get_address_space(dev);
>   }
>   
> +static bool virtio_pci_queue_enabled(DeviceState *d, int n)
> +{
> +    VirtIOPCIProxy *proxy = VIRTIO_PCI(d);
> +    VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
> +
> +    if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
> +        return proxy->vqs[vdev->queue_sel].enabled;
> +    }
> +
> +    return virtio_queue_get_desc_addr(vdev, n) != 0;
> +}
> +
>   static int virtio_pci_add_mem_cap(VirtIOPCIProxy *proxy,
>                                      struct virtio_pci_cap *cap)
>   {
> @@ -2053,6 +2065,7 @@ static void virtio_pci_bus_class_init(ObjectClass *klass, void *data)
>       k->ioeventfd_enabled = virtio_pci_ioeventfd_enabled;
>       k->ioeventfd_assign = virtio_pci_ioeventfd_assign;
>       k->get_dma_as = virtio_pci_get_dma_as;
> +    k->queue_enabled = virtio_pci_queue_enabled;
>   }
>   
>   static const TypeInfo virtio_pci_bus_info = {
> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
> index 04716b5f6c..09732a8836 100644
> --- a/hw/virtio/virtio.c
> +++ b/hw/virtio/virtio.c
> @@ -3169,6 +3169,12 @@ hwaddr virtio_queue_get_desc_addr(VirtIODevice *vdev, int n)
>   
>   bool virtio_queue_enabled(VirtIODevice *vdev, int n)
>   {
> +    BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
> +    VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
> +
> +    if (k->queue_enabled)
> +        return k->queue_enabled(qbus->parent, n);
> +
>       return virtio_queue_get_desc_addr(vdev, n) != 0;
>   }
>   
> diff --git a/include/hw/virtio/vhost-backend.h b/include/hw/virtio/vhost-backend.h
> index d81bd9885f..ce8de6d308 100644
> --- a/include/hw/virtio/vhost-backend.h
> +++ b/include/hw/virtio/vhost-backend.h
> @@ -78,6 +78,7 @@ typedef int (*vhost_reset_device_op)(struct vhost_dev *dev);
>   typedef int (*vhost_get_vq_index_op)(struct vhost_dev *dev, int idx);
>   typedef int (*vhost_set_vring_enable_op)(struct vhost_dev *dev,
>                                            int enable);
> +typedef int (*vhost_set_vring_ready_op)(struct vhost_dev *dev);
>   typedef bool (*vhost_requires_shm_log_op)(struct vhost_dev *dev);
>   typedef int (*vhost_migration_done_op)(struct vhost_dev *dev,
>                                          char *mac_addr);
> @@ -140,6 +141,7 @@ typedef struct VhostOps {
>       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;
> +    vhost_set_vring_ready_op vhost_set_vring_ready;
>       vhost_requires_shm_log_op vhost_requires_shm_log;
>       vhost_migration_done_op vhost_migration_done;
>       vhost_backend_can_merge_op vhost_backend_can_merge;
> diff --git a/include/hw/virtio/virtio-bus.h b/include/hw/virtio/virtio-bus.h
> index 38c9399cd4..0f6f215925 100644
> --- a/include/hw/virtio/virtio-bus.h
> +++ b/include/hw/virtio/virtio-bus.h
> @@ -83,6 +83,10 @@ typedef struct VirtioBusClass {
>        */
>       int (*ioeventfd_assign)(DeviceState *d, EventNotifier *notifier,
>                               int n, bool assign);
> +    /*
> +     * Whether queue number n is enabled.
> +     */
> +    bool (*queue_enabled)(DeviceState *d, int n);
>       /*
>        * Does the transport have variable vring alignment?
>        * (ie can it ever call virtio_queue_set_align()?)
> diff --git a/include/net/vhost_net.h b/include/net/vhost_net.h
> index 6f3a624cf7..db473ff4d2 100644
> --- a/include/net/vhost_net.h
> +++ b/include/net/vhost_net.h
> @@ -35,6 +35,7 @@ int vhost_net_notify_migration_done(VHostNetState *net, char* mac_addr);
>   VHostNetState *get_vhost_net(NetClientState *nc);
>   
>   int vhost_set_vring_enable(NetClientState * nc, int enable);
> +int vhost_set_vring_ready(NetClientState * nc);
>   
>   uint64_t vhost_net_get_acked_features(VHostNetState *net);
>