vhost-blk: turn on pre-defined RO feature bit

Read only feature shouldn't be negotiable, because if the
backend device reported Read only feature supported, QEMU
host driver shouldn't change backend's RO attribute. While
here, also enable the vhost-user-blk test utility to test
RO feature.

Signed-off-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 35 insertions, 13 deletions

diff --git a/contrib/vhost-user-blk/vhost-user-blk.c b/contrib/vhost-user-blk/vhost-user-blk.c
index a6a132a492..571f114a56 100644
--- a/contrib/vhost-user-blk/vhost-user-blk.c
+++ b/contrib/vhost-user-blk/vhost-user-blk.c
@@ -31,6 +31,7 @@ typedef struct VubDev {
     VugDev parent;
     int blk_fd;
     struct virtio_blk_config blkcfg;
+    bool enable_ro;
     char *blk_name;
     GMainLoop *loop;
 } VubDev;
@@ -301,14 +302,27 @@ static void vub_queue_set_started(VuDev *vu_dev, int idx, bool started)
 static uint64_t
 vub_get_features(VuDev *dev)
 {
-    return 1ull << VIRTIO_BLK_F_SIZE_MAX |
-           1ull << VIRTIO_BLK_F_SEG_MAX |
-           1ull << VIRTIO_BLK_F_TOPOLOGY |
-           1ull << VIRTIO_BLK_F_BLK_SIZE |
-           1ull << VIRTIO_BLK_F_FLUSH |
-           1ull << VIRTIO_BLK_F_CONFIG_WCE |
-           1ull << VIRTIO_F_VERSION_1 |
-           1ull << VHOST_USER_F_PROTOCOL_FEATURES;
+    uint64_t features;
+    VugDev *gdev;
+    VubDev *vdev_blk;
+
+    gdev = container_of(dev, VugDev, parent);
+    vdev_blk = container_of(gdev, VubDev, parent);
+
+    features = 1ull << VIRTIO_BLK_F_SIZE_MAX |
+               1ull << VIRTIO_BLK_F_SEG_MAX |
+               1ull << VIRTIO_BLK_F_TOPOLOGY |
+               1ull << VIRTIO_BLK_F_BLK_SIZE |
+               1ull << VIRTIO_BLK_F_FLUSH |
+               1ull << VIRTIO_BLK_F_CONFIG_WCE |
+               1ull << VIRTIO_F_VERSION_1 |
+               1ull << VHOST_USER_F_PROTOCOL_FEATURES;
+
+    if (vdev_blk->enable_ro) {
+        features |= 1ull << VIRTIO_BLK_F_RO;
+    }
+
+    return features;
 }
 
 static uint64_t
@@ -476,6 +490,7 @@ vub_new(char *blk_file)
         vub_free(vdev_blk);
         return NULL;
     }
+    vdev_blk->enable_ro = false;
     vdev_blk->blkcfg.wce = 0;
     vdev_blk->blk_name = blk_file;
 
@@ -490,10 +505,11 @@ int main(int argc, char **argv)
     int opt;
     char *unix_socket = NULL;
     char *blk_file = NULL;
+    bool enable_ro = false;
     int lsock = -1, csock = -1;
     VubDev *vdev_blk = NULL;
 
-    while ((opt = getopt(argc, argv, "b:s:h")) != -1) {
+    while ((opt = getopt(argc, argv, "b:rs:h")) != -1) {
         switch (opt) {
         case 'b':
             blk_file = g_strdup(optarg);
@@ -501,17 +517,20 @@ int main(int argc, char **argv)
         case 's':
             unix_socket = g_strdup(optarg);
             break;
+        case 'r':
+            enable_ro = true;
+            break;
         case 'h':
         default:
-            printf("Usage: %s [-b block device or file, -s UNIX domain socket]"
-                   " | [ -h ]\n", argv[0]);
+            printf("Usage: %s [ -b block device or file, -s UNIX domain socket"
+                   " | -r Enable read-only ] | [ -h ]\n", argv[0]);
             return 0;
         }
     }
 
     if (!unix_socket || !blk_file) {
-        printf("Usage: %s [-b block device or file, -s UNIX domain socket] |"
-               " [ -h ]\n", argv[0]);
+        printf("Usage: %s [ -b block device or file, -s UNIX domain socket"
+               " | -r Enable read-only ] | [ -h ]\n", argv[0]);
         return -1;
     }
 
@@ -530,6 +549,9 @@ int main(int argc, char **argv)
     if (!vdev_blk) {
         goto err;
     }
+    if (enable_ro) {
+        vdev_blk->enable_ro = true;
+    }
 
     vug_init(&vdev_blk->parent, csock, vub_panic_cb, &vub_iface);