vmm, config, vhost_user_blk: remove "wce" parameter

This config option provided very little value and instead we now enable
this feature (which then lets the guest control the cache mode)
unconditionally.

Signed-off-by: Rob Bradford <robert.bradford@intel.com>

docs/vhost-user-blk-testing.md

@@ -76,7 +76,7 @@ VMs run in client mode. They connect to the socket created by the `dpdkvhostuser
         --memory size=1024M,file=/dev/hugepages \
         --kernel linux/arch/x86/boot/compressed/vmlinux.bin \
         --cmdline "console=ttyS0 reboot=k panic=1 nomodules i8042.noaux i8042.nomux i8042.nopnp i8042.dumbkbd root=/dev/vda3 iommu=off" \
-        --disk "path=images/clear-kvm.img" "num_queues=4,queue_size=128,vhost_user=true,socket=/var/tmp/vhost.1,wce=true" \
+        --disk "path=images/clear-kvm.img" "num_queues=4,queue_size=128,vhost_user=true,socket=/var/tmp/vhost.1" \
         --console off \
         --serial tty \
         --rng

src/main.rs

@@ -763,14 +763,14 @@ mod unit_tests {
                     "--memory",
                     "shared=true",
                     "--disk",
-                    "vhost_user=true,socket=/tmp/socket1,wce=true",
+                    "vhost_user=true,socket=/tmp/socket1",
                     "path=/path/to/disk/2",
                 ],
                 r#"{
                     "kernel": {"path": "/path/to/kernel"},
                     "memory" : { "shared": true, "size": 536870912 },
                     "disks": [
-                        {"vhost_user":true, "vhost_socket":"/tmp/socket1", "wce":true},
+                        {"vhost_user":true, "vhost_socket":"/tmp/socket1"},
                         {"path": "/path/to/disk/2"}
                     ]
                 }"#,

tests/integration.rs

@@ -1539,7 +1539,7 @@ mod tests {
 
                 (
                     format!(
-                        "vhost_user=true,path={},num_queues={},queue_size=128,wce=true",
+                        "vhost_user=true,path={},num_queues={},queue_size=128",
                         blk_file_path, num_queues,
                     ),
                     None,
@@ -1552,7 +1552,7 @@ mod tests {
 
                 (
                     format!(
-                        "vhost_user=true,socket={},num_queues={},queue_size=128,wce=true",
+                        "vhost_user=true,socket={},num_queues={},queue_size=128",
                         vubd_socket_path, num_queues,
                     ),
                     Some(daemon_child),
@@ -1736,7 +1736,7 @@ mod tests {
             let (blk_boot_params, daemon_child) = if self_spawned {
                 (
                     format!(
-                        "vhost_user=true,path={},num_queues={},queue_size=128,wce=true",
+                        "vhost_user=true,path={},num_queues={},queue_size=128",
                         disk_path, num_queues,
                     ),
                     None,
@@ -1754,7 +1754,7 @@ mod tests {
 
                 (
                     format!(
-                        "vhost_user=true,socket={},num_queues={},queue_size=128,wce=true",
+                        "vhost_user=true,socket={},num_queues={},queue_size=128",
                         vubd_socket_path, num_queues,
                     ),
                     Some(daemon_child),

vm-virtio/src/vhost_user/blk.rs

@@ -50,7 +50,7 @@ pub struct Blk {
 
 impl Blk {
     /// Create a new vhost-user-blk device
-    pub fn new(id: String, wce: bool, vu_cfg: VhostUserConfig) -> Result<Blk> {
+    pub fn new(id: String, vu_cfg: VhostUserConfig) -> Result<Blk> {
         let mut vhost_user_blk = Master::connect(&vu_cfg.sock, vu_cfg.num_queues as u64)
             .map_err(Error::VhostUserCreateMaster)?;
 
@@ -61,13 +61,10 @@ impl Blk {
             | 1 << VIRTIO_BLK_F_FLUSH
             | 1 << VIRTIO_BLK_F_TOPOLOGY
             | 1 << VIRTIO_RING_F_EVENT_IDX
+            | 1 << VIRTIO_BLK_F_CONFIG_WCE
             | 1 << VIRTIO_F_VERSION_1
             | VhostUserVirtioFeatures::PROTOCOL_FEATURES.bits();
 
-        if wce {
-            avail_features |= 1 << VIRTIO_BLK_F_CONFIG_WCE;
-        }
-
         if vu_cfg.num_queues > 1 {
             avail_features |= 1 << VIRTIO_BLK_F_MQ;
         }

vmm/src/api/openapi/cloud-hypervisor.yaml

@@ -454,9 +454,6 @@ components:
           default: false
         vhost_socket:
           type: string
-        wce:
-          type: boolean
-          default: true
         poll_queue:
           type: boolean
           default: true

vmm/src/config.rs

@@ -561,8 +561,6 @@ pub struct DiskConfig {
     #[serde(default)]
     pub vhost_user: bool,
     pub vhost_socket: Option<String>,
-    #[serde(default = "default_diskconfig_wce")]
-    pub wce: bool,
     #[serde(default = "default_diskconfig_poll_queue")]
     pub poll_queue: bool,
     #[serde(default)]
@@ -577,10 +575,6 @@ fn default_diskconfig_queue_size() -> u16 {
     DEFAULT_QUEUE_SIZE_VUBLK
 }
 
-fn default_diskconfig_wce() -> bool {
-    true
-}
-
 fn default_diskconfig_poll_queue() -> bool {
     true
 }
@@ -596,7 +590,6 @@ impl Default for DiskConfig {
             queue_size: default_diskconfig_queue_size(),
             vhost_user: false,
             vhost_socket: None,
-            wce: default_diskconfig_wce(),
             poll_queue: default_diskconfig_poll_queue(),
             id: None,
         }
@@ -607,7 +600,7 @@ impl DiskConfig {
     pub const SYNTAX: &'static str = "Disk parameters \
          \"path=<disk_image_path>,readonly=on|off,iommu=on|off,num_queues=<number_of_queues>,\
          queue_size=<size_of_each_queue>,vhost_user=<vhost_user_enable>,\
-         socket=<vhost_user_socket_path>,wce=<true|false, default true>,id=<device_id>\"";
+         socket=<vhost_user_socket_path>, default true>,id=<device_id>\"";
 
     pub fn parse(disk: &str) -> Result<Self> {
         let mut parser = OptionParser::new();
@@ -620,7 +613,6 @@ impl DiskConfig {
             .add("num_queues")
             .add("vhost_user")
             .add("socket")
-            .add("wce")
             .add("poll_queue")
             .add("id");
         parser.parse(disk).map_err(Error::ParseDisk)?;
@@ -655,11 +647,6 @@ impl DiskConfig {
             .unwrap_or(Toggle(false))
             .0;
         let vhost_socket = parser.get("socket");
-        let wce = parser
-            .convert::<Toggle>("wce")
-            .map_err(Error::ParseDisk)?
-            .unwrap_or_else(|| Toggle(default_diskconfig_wce()))
-            .0;
         let poll_queue = parser
             .convert::<Toggle>("poll_queue")
             .map_err(Error::ParseDisk)?
@@ -667,10 +654,6 @@ impl DiskConfig {
             .0;
         let id = parser.get("id");
 
-        if parser.is_set("wce") && !vhost_user {
-            warn!("wce parameter currently only has effect when used vhost_user=true");
-        }
-
         if parser.is_set("poll_queue") && !vhost_user {
             warn!("poll_queue parameter currently only has effect when used vhost_user=true");
         }
@@ -684,7 +667,6 @@ impl DiskConfig {
             queue_size,
             vhost_socket,
             vhost_user,
-            wce,
             poll_queue,
             id,
         })
@@ -1611,18 +1593,16 @@ mod tests {
             }
         );
         assert_eq!(
-            DiskConfig::parse("path=/path/to_file,wce=true")?,
+            DiskConfig::parse("path=/path/to_file")?,
             DiskConfig {
                 path: Some(PathBuf::from("/path/to_file")),
-                wce: true,
                 ..Default::default()
             }
         );
         assert_eq!(
-            DiskConfig::parse("path=/path/to_file,wce=false")?,
+            DiskConfig::parse("path=/path/to_file")?,
             DiskConfig {
                 path: Some(PathBuf::from("/path/to_file")),
-                wce: false,
                 ..Default::default()
             }
         );

vmm/src/device_manager.rs

@@ -1336,7 +1336,7 @@ impl DeviceManager {
                 queue_size: disk_cfg.queue_size,
             };
             let vhost_user_block_device = Arc::new(Mutex::new(
-                vm_virtio::vhost_user::Blk::new(id.clone(), disk_cfg.wce, vu_cfg)
+                vm_virtio::vhost_user::Blk::new(id.clone(), vu_cfg)
                     .map_err(DeviceManagerError::CreateVhostUserBlk)?,
             ));