vdpa: add new attribute VDPA_ATTR_DEV_MIN_VQ_SIZE

This attribute advertises the min value of virtqueue size. The value is
1 by default.

Signed-off-by: Wu Zongyong <wuzongyong@linux.alibaba.com>
Link: https://lore.kernel.org/r/2bbc417355c4d22298050b1ba887cecfbde3e85d.1635493219.git.wuzongyong@linux.alibaba.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index d783a94..fcf02a3 100644 (file)
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c
@@ -500,6 +500,7 @@ vdpa_dev_fill(struct vdpa_device *vdev, struct sk_buff *msg, u32 portid, u32 seq
              int flags, struct netlink_ext_ack *extack)
 {
        u16 max_vq_size;
+       u16 min_vq_size = 1;
        u32 device_id;
        u32 vendor_id;
        void *hdr;
@@ -516,6 +517,8 @@ vdpa_dev_fill(struct vdpa_device *vdev, struct sk_buff *msg, u32 portid, u32 seq
        device_id = vdev->config->get_device_id(vdev);
        vendor_id = vdev->config->get_vendor_id(vdev);
        max_vq_size = vdev->config->get_vq_num_max(vdev);
+       if (vdev->config->get_vq_num_min)
+               min_vq_size = vdev->config->get_vq_num_min(vdev);
 
        err = -EMSGSIZE;
        if (nla_put_string(msg, VDPA_ATTR_DEV_NAME, dev_name(&vdev->dev)))
@@ -528,6 +531,8 @@ vdpa_dev_fill(struct vdpa_device *vdev, struct sk_buff *msg, u32 portid, u32 seq
                goto msg_err;
        if (nla_put_u16(msg, VDPA_ATTR_DEV_MAX_VQ_SIZE, max_vq_size))
                goto msg_err;
+       if (nla_put_u16(msg, VDPA_ATTR_DEV_MIN_VQ_SIZE, min_vq_size))
+               goto msg_err;
 
        genlmsg_end(msg, hdr);
        return 0;

diff --git a/include/uapi/linux/vdpa.h b/include/uapi/linux/vdpa.h
index 66a41e4..e3b8787 100644 (file)
--- a/include/uapi/linux/vdpa.h
+++ b/include/uapi/linux/vdpa.h
@@ -32,6 +32,7 @@ enum vdpa_attr {
        VDPA_ATTR_DEV_VENDOR_ID,                /* u32 */
        VDPA_ATTR_DEV_MAX_VQS,                  /* u32 */
        VDPA_ATTR_DEV_MAX_VQ_SIZE,              /* u16 */
+       VDPA_ATTR_DEV_MIN_VQ_SIZE,              /* u16 */
 
        /* new attributes must be added above here */
        VDPA_ATTR_MAX,