Merge pull request kata-containers#10711 from teawater/balloon

Add reclaim_guest_freed_memory config to qemu and cloud-hypervisor

src/libs/kata-types/src/config/hypervisor/mod.rs

@@ -499,7 +499,7 @@ pub struct DeviceInfo {
     ///
     /// Enabling this will result in the VM balloon device having f_reporting=on set
     #[serde(default)]
-    pub enable_balloon_f_reporting: bool,
+    pub reclaim_guest_freed_memory: bool,
 }
 
 impl DeviceInfo {

src/runtime-rs/config/configuration-cloud-hypervisor.toml.in

@@ -158,6 +158,16 @@ virtio_fs_cache = "@DEFVIRTIOFSCACHE@"
 # > 5                --> will be set to 5
 default_bridges = @DEFBRIDGES@
 
+# Reclaim guest freed memory.
+# Enabling this will result in the VM balloon device having f_reporting=on set.
+# Then the hypervisor will use it to reclaim guest freed memory.
+# This is useful for reducing the amount of memory used by a VM.
+# Enabling this feature may sometimes reduce the speed of memory access in
+# the VM.
+#
+# Default false
+#reclaim_guest_freed_memory = true
+
 # Block storage driver to be used for the hypervisor in case the container
 # rootfs is backed by a block device.
 block_device_driver = "virtio-blk-pci"

src/runtime-rs/config/configuration-dragonball.toml.in

@@ -98,11 +98,15 @@ default_maxvcpus = @DEFMAXVCPUS_DB@
 # > 5                --> will be set to 5
 default_bridges = @DEFBRIDGES@
 
-# Enable balloon f_reporting
-# Enabling this will result in the VM balloon device having f_reporting=on set
+# Reclaim guest freed memory.
+# Enabling this will result in the VM balloon device having f_reporting=on set.
+# Then the hypervisor will use it to reclaim guest freed memory.
+# This is useful for reducing the amount of memory used by a VM.
+# Enabling this feature may sometimes reduce the speed of memory access in
+# the VM.
 #
 # Default false
-#enable_balloon_f_reporting = true
+#reclaim_guest_freed_memory = true
 
 # Default memory size in MiB for SB/VM.
 # If unspecified then it will be set @DEFMEMSZ@ MiB.

src/runtime-rs/config/configuration-qemu-runtime-rs.toml.in

@@ -143,6 +143,16 @@ default_maxvcpus = @DEFMAXVCPUS_QEMU@
 # > 5                --> will be set to 5
 default_bridges = @DEFBRIDGES@
 
+# Reclaim guest freed memory.
+# Enabling this will result in the VM balloon device having f_reporting=on set.
+# Then the hypervisor will use it to reclaim guest freed memory.
+# This is useful for reducing the amount of memory used by a VM.
+# Enabling this feature may sometimes reduce the speed of memory access in
+# the VM.
+#
+# Default false
+#reclaim_guest_freed_memory = true
+
 # Default memory size in MiB for SB/VM.
 # If unspecified then it will be set @DEFMEMSZ@ MiB.
 default_memory = @DEFMEMSZ@

src/runtime-rs/crates/hypervisor/ch-config/src/convert.rs

@@ -180,6 +180,15 @@ impl TryFrom<NamedHypervisorConfig> for VmConfig {
 
         let platform = get_platform_cfg(guest_protection_to_use);
 
+        let balloon = if cfg.device_info.reclaim_guest_freed_memory {
+            Some(crate::BalloonConfig {
+                free_page_reporting: true,
+                ..Default::default()
+            })
+        } else {
+            None
+        };
+
         let cfg = VmConfig {
             cpus,
             memory,
@@ -193,6 +202,7 @@ impl TryFrom<NamedHypervisorConfig> for VmConfig {
             vsock: Some(vsock),
             rng,
             platform,
+            balloon,
 
             ..Default::default()
         };

src/runtime-rs/crates/hypervisor/src/dragonball/inner.rs

@@ -430,7 +430,7 @@ impl DragonballInner {
                         use_shared_irq: None,
                         use_generic_irq: None,
                         f_deflate_on_oom: false,
-                        f_reporting: self.config.device_info.enable_balloon_f_reporting,
+                        f_reporting: self.config.device_info.reclaim_guest_freed_memory,
                     };
                     self.vmm_instance
                         .insert_balloon_device(balloon_config)
@@ -462,7 +462,7 @@ impl DragonballInner {
                     use_shared_irq: None,
                     use_generic_irq: None,
                     f_deflate_on_oom: false,
-                    f_reporting: self.config.device_info.enable_balloon_f_reporting,
+                    f_reporting: self.config.device_info.reclaim_guest_freed_memory,
                 };
                 self.balloon_size = had_mem_mb - new_mem_mb;
                 self.vmm_instance

src/runtime-rs/crates/hypervisor/src/dragonball/mod.rs

@@ -85,7 +85,7 @@ impl Hypervisor for Dragonball {
         let mut inner = self.inner.write().await;
         let ret = inner.start_vm(timeout).await;
 
-        if ret.is_ok() && inner.config.device_info.enable_balloon_f_reporting {
+        if ret.is_ok() && inner.config.device_info.reclaim_guest_freed_memory {
             // The virtio-balloon device must be inserted into dragonball and
             // recognized by the guest kernel only after the dragonball upcall is ready.
             // The dragonball upcall is not ready immediately after the VM starts,

src/runtime-rs/crates/hypervisor/src/qemu/cmdline_generator.rs

@@ -1793,6 +1793,10 @@ impl<'a> QemuCmdLine<'a> {
             qemu_cmd_line.add_scsi_controller();
         }
 
+        if config.device_info.reclaim_guest_freed_memory {
+            qemu_cmd_line.add_virtio_balloon();
+        }
+
         Ok(qemu_cmd_line)
     }
 
@@ -2007,6 +2011,11 @@ impl<'a> QemuCmdLine<'a> {
         self.devices.push(Box::new(console_socket_chardev));
     }
 
+    pub fn add_virtio_balloon(&mut self) {
+        let balloon_device = DeviceVirtioBalloon::new();
+        self.devices.push(Box::new(balloon_device));
+    }
+
     pub async fn build(&self) -> Result<Vec<String>> {
         let mut result = Vec::new();
 
@@ -2071,3 +2080,22 @@ fn get_devno_ccw(ccw_subchannel: &mut Option<CcwSubChannel>, device_name: &str)
         )
     })
 }
+
+#[derive(Debug)]
+struct DeviceVirtioBalloon {}
+
+impl DeviceVirtioBalloon {
+    fn new() -> Self {
+        DeviceVirtioBalloon {}
+    }
+}
+
+#[async_trait]
+impl ToQemuParams for DeviceVirtioBalloon {
+    async fn qemu_params(&self) -> Result<Vec<String>> {
+        Ok(vec![
+            "-device".to_owned(),
+            "virtio-balloon,free-page-reporting=on".to_owned(),
+        ])
+    }
+}

tools/packaging/kernel/configs/fragments/common/virtio.conf

@@ -23,3 +23,5 @@ CONFIG_VIRTIO_BLK=y
 CONFIG_TTY=y
 CONFIG_VIRTIO_CONSOLE=y
 CONFIG_VIRTIO_NET=y
+
+CONFIG_VIRTIO_BALLOON=y

tools/packaging/kernel/kata_config_version

@@ -1 +1 @@
-142
+143