[PATCH v1 3/5] vhost-user-blk: make it possible to disable write-zeroes/discard

[Daniil Tatianin]

It is useful to have the ability to disable these features for
compatibility with older VMs that don't have these implemented.

Signed-off-by: Daniil Tatianin <d-tatianin@yandex-team.ru>
---
 hw/block/vhost-user-blk.c          | 8 ++++++--
 include/hw/virtio/vhost-user-blk.h | 2 ++
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c
index 9117222456..e89164c358 100644
--- a/hw/block/vhost-user-blk.c
+++ b/hw/block/vhost-user-blk.c
@@ -251,6 +251,8 @@ static uint64_t vhost_user_blk_get_features(VirtIODevice 
*vdev,
 {
     VHostUserBlk *s = VHOST_USER_BLK(vdev);
 
+    features |= s->host_features;
+
     /* Turn on pre-defined features */
     virtio_add_feature(&features, VIRTIO_BLK_F_SIZE_MAX);
     virtio_add_feature(&features, VIRTIO_BLK_F_SEG_MAX);
@@ -259,8 +261,6 @@ static uint64_t vhost_user_blk_get_features(VirtIODevice 
*vdev,
     virtio_add_feature(&features, VIRTIO_BLK_F_BLK_SIZE);
     virtio_add_feature(&features, VIRTIO_BLK_F_FLUSH);
     virtio_add_feature(&features, VIRTIO_BLK_F_RO);
-    virtio_add_feature(&features, VIRTIO_BLK_F_DISCARD);
-    virtio_add_feature(&features, VIRTIO_BLK_F_WRITE_ZEROES);
 
     if (s->config_wce) {
         virtio_add_feature(&features, VIRTIO_BLK_F_CONFIG_WCE);
@@ -592,6 +592,10 @@ static Property vhost_user_blk_properties[] = {
                        VHOST_USER_BLK_AUTO_NUM_QUEUES),
     DEFINE_PROP_UINT32("queue-size", VHostUserBlk, queue_size, 128),
     DEFINE_PROP_BIT("config-wce", VHostUserBlk, config_wce, 0, true),
+    DEFINE_PROP_BIT64("discard", VHostUserBlk, host_features,
+                      VIRTIO_BLK_F_DISCARD, true),
+    DEFINE_PROP_BIT64("write-zeroes", VHostUserBlk, host_features,
+                      VIRTIO_BLK_F_WRITE_ZEROES, true),
     DEFINE_PROP_END_OF_LIST(),
 };
 
diff --git a/include/hw/virtio/vhost-user-blk.h 
b/include/hw/virtio/vhost-user-blk.h
index 7c91f15040..20573dd586 100644
--- a/include/hw/virtio/vhost-user-blk.h
+++ b/include/hw/virtio/vhost-user-blk.h
@@ -51,6 +51,8 @@ struct VHostUserBlk {
     bool connected;
     /* vhost_user_blk_start/vhost_user_blk_stop */
     bool started_vu;
+
+    uint64_t host_features;
 };
 
 #endif
-- 
2.25.1