vDPA: report virtio-block max segments in a request to user space

This commit allows vDPA reporting the maximum number of
segments in a request of virtio-block devices to
user space.

Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
Message-Id: <20240218185606.13509-5-lingshan.zhu@intel.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index d96dc2ad48aa484e235c1dd9075d9f18760268af..3e3c84bd0337968513b012b278234a7a9ba42e18 100644 (file)
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c
@@ -985,6 +985,20 @@ vdpa_dev_blk_block_size_config_fill(struct sk_buff *msg, u64 features,
        return nla_put_u32(msg, VDPA_ATTR_DEV_BLK_CFG_BLK_SIZE, val_u32);
 }
 
+static int
+vdpa_dev_blk_seg_max_config_fill(struct sk_buff *msg, u64 features,
+                                const struct virtio_blk_config *config)
+{
+       u32 val_u32;
+
+       if ((features & BIT_ULL(VIRTIO_BLK_F_SEG_MAX)) == 0)
+               return 0;
+
+       val_u32 = __virtio32_to_cpu(true, config->seg_max);
+
+       return nla_put_u32(msg, VDPA_ATTR_DEV_BLK_CFG_SEG_MAX, val_u32);
+}
+
 static int vdpa_dev_blk_config_fill(struct vdpa_device *vdev,
                                    struct sk_buff *msg)
 {
@@ -1008,6 +1022,9 @@ static int vdpa_dev_blk_config_fill(struct vdpa_device *vdev,
        if (vdpa_dev_blk_block_size_config_fill(msg, features_device, &config))
                return -EMSGSIZE;
 
+       if (vdpa_dev_blk_seg_max_config_fill(msg, features_device, &config))
+               return -EMSGSIZE;
+
        return 0;
 }
 

diff --git a/include/uapi/linux/vdpa.h b/include/uapi/linux/vdpa.h
index f3baf7ea7d6d9182cca1eb265b1494440f50505d..2dc92fca2052ec82cc2643eb56d055b058a4b792 100644 (file)
--- a/include/uapi/linux/vdpa.h
+++ b/include/uapi/linux/vdpa.h
@@ -59,6 +59,7 @@ enum vdpa_attr {
        VDPA_ATTR_DEV_BLK_CFG_CAPACITY,         /* u64 */
        VDPA_ATTR_DEV_BLK_CFG_SEG_SIZE,         /* u32 */
        VDPA_ATTR_DEV_BLK_CFG_BLK_SIZE,         /* u32 */
+       VDPA_ATTR_DEV_BLK_CFG_SEG_MAX,          /* u32 */
 
        /* new attributes must be added above here */
        VDPA_ATTR_MAX,