runtime-rs: remove file_mem_backend config option

While the config knob is being parsed, it is being unused in the
rust shim. This renders the config knob useless. Remove the
file_mem_backend config option as there is no current users for it.
As this option is being usable in the go shim, we leave it intact.

For the rust shim, /dev/shm is still being used in a similar way to
the go shim when filesystem sharing is enabled (virtio-fs). Future
use cases where other file_mem_backends are being utilized are
currently planning to define these backends in a similar manner:
based on the configuration/platform, determine the proper file
memory backend, but do not let end users determine the file memory
backend.

Signed-off-by: Manuel Huber <manuelh@nvidia.com>

docs/how-to/how-to-run-kata-containers-with-SNP-VMs.md

@@ -108,7 +108,7 @@ shared_fs = "none"
 ```toml
 disable_image_nvdimm = true
 ```
-- Disable shared memory (uncomment)
+- Disable shared memory (uncomment; only applies to Go runtime)
 ```toml
 file_mem_backend = ""
 ```

src/libs/kata-types/src/annotations/mod.rs

@@ -235,9 +235,6 @@ pub const KATA_ANNO_CFG_HYPERVISOR_ENABLE_HUGEPAGES: &str =
 /// A sandbox annotation to specify huge page mode of memory backend.
 pub const KATA_ANNO_CFG_HYPERVISOR_HUGEPAGE_TYPE: &str =
     "io.katacontainers.config.hypervisor.hugepage_type";
-/// A sandbox annotation to soecify file based memory backend root directory.
-pub const KATA_ANNO_CFG_HYPERVISOR_FILE_BACKED_MEM_ROOT_DIR: &str =
-    "io.katacontainers.config.hypervisor.file_mem_backend";
 /// A sandbox annotation that is used to enable/disable virtio-mem.
 pub const KATA_ANNO_CFG_HYPERVISOR_VIRTIO_MEM: &str =
     "io.katacontainers.config.hypervisor.enable_virtio_mem";
@@ -889,10 +886,6 @@ impl Annotation {
                             }
                         }
                     }
-                    KATA_ANNO_CFG_HYPERVISOR_FILE_BACKED_MEM_ROOT_DIR => {
-                        hv.memory_info.validate_memory_backend_path(value)?;
-                        hv.memory_info.file_mem_backend = value.to_string();
-                    }
                     KATA_ANNO_CFG_HYPERVISOR_VIRTIO_MEM => match self.get_value::<bool>(key) {
                         Ok(r) => {
                             hv.memory_info.enable_virtio_mem = r.unwrap_or_default();

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

@@ -986,18 +986,6 @@ pub struct MemoryInfo {
     #[serde(default)]
     pub memory_slots: u32,
 
-    /// File-based guest memory support path.
-    ///
-    /// Disabled by default. Automatically set to `/dev/shm` for virtio-fs.
-    #[serde(default)]
-    pub file_mem_backend: String,
-
-    /// Valid file memory backends for annotations.
-    ///
-    /// Default: empty (all annotations rejected)
-    #[serde(default)]
-    pub valid_file_mem_backends: Vec<String>,
-
     /// Pre-allocate VM RAM (reduces container density).
     #[serde(default)]
     pub enable_mem_prealloc: bool,
@@ -1101,15 +1089,9 @@ fn host_memory_mib() -> io::Result<u64> {
 impl MemoryInfo {
     /// Adjusts the configuration information after loading from a configuration file.
     ///
-    /// This method resolves the path for the file memory backend and
-    /// sets `default_maxmemory` if it's currently zero, calculating it
-    /// from the total system memory.
+    /// This method sets `default_maxmemory` if it's currently zero,
+    /// calculating it from the total system memory.
     pub fn adjust_config(&mut self) -> Result<()> {
-        resolve_path!(
-            self.file_mem_backend,
-            "Memory backend file {} is invalid: {}"
-        )?;
-
         let host_memory = host_memory_mib()?;
 
         if u64::from(self.default_memory) > host_memory {
@@ -1200,13 +1182,8 @@ impl MemoryInfo {
     /// Validates the memory configuration information.
     ///
     /// This ensures that critical memory parameters like `default_memory`
-    /// and `memory_slots` are non-zero, and checks the validity of
-    /// the memory backend file path.
+    /// and `memory_slots` are non-zero.
     pub fn validate(&self) -> Result<()> {
-        validate_path!(
-            self.file_mem_backend,
-            "Memory backend file {} is invalid: {}"
-        )?;
         if self.default_memory == 0 {
             return Err(std::io::Error::other(
                 "Configured memory size for guest VM is zero",
@@ -1220,11 +1197,6 @@ impl MemoryInfo {
 
         Ok(())
     }
-
-    /// Validates the path of memory backend files against configured patterns.
-    pub fn validate_memory_backend_path<P: AsRef<Path>>(&self, path: P) -> Result<()> {
-        validate_path_pattern(&self.valid_file_mem_backends, path)
-    }
 }
 
 /// Configuration information for network settings.

src/libs/kata-types/tests/test_config.rs

@@ -13,7 +13,6 @@ mod tests {
         KATA_ANNO_CFG_HYPERVISOR_BLOCK_DEV_DRIVER, KATA_ANNO_CFG_HYPERVISOR_DEFAULT_MEMORY,
         KATA_ANNO_CFG_HYPERVISOR_DEFAULT_VCPUS, KATA_ANNO_CFG_HYPERVISOR_ENABLE_GUEST_SWAP,
         KATA_ANNO_CFG_HYPERVISOR_ENABLE_HUGEPAGES, KATA_ANNO_CFG_HYPERVISOR_ENABLE_IO_THREADS,
-        KATA_ANNO_CFG_HYPERVISOR_FILE_BACKED_MEM_ROOT_DIR,
         KATA_ANNO_CFG_HYPERVISOR_GUEST_HOOK_PATH, KATA_ANNO_CFG_HYPERVISOR_INDEP_IO_THREADS,
         KATA_ANNO_CFG_HYPERVISOR_JAILER_PATH, KATA_ANNO_CFG_HYPERVISOR_KERNEL_PATH,
         KATA_ANNO_CFG_HYPERVISOR_MEMORY_PREALLOC, KATA_ANNO_CFG_HYPERVISOR_MEMORY_SLOTS,
@@ -52,10 +51,6 @@ mod tests {
             .arg("./jvm")
             .output()
             .expect("failed to execute process");
-        std::process::Command::new("mkdir")
-            .arg("./test_file_backend_mem_root")
-            .output()
-            .expect("failed to execute process");
         std::process::Command::new("mkdir")
             .arg("./test_jailer_path")
             .output()
@@ -131,10 +126,6 @@ mod tests {
             KATA_ANNO_CFG_HYPERVISOR_ENABLE_IO_THREADS.to_string(),
             "false".to_string(),
         );
-        anno_hash.insert(
-            KATA_ANNO_CFG_HYPERVISOR_FILE_BACKED_MEM_ROOT_DIR.to_string(),
-            "./test_file_backend_mem_root".to_string(),
-        );
         anno_hash.insert(
             KATA_ANNO_CFG_HYPERVISOR_ENABLE_HUGEPAGES.to_string(),
             "false".to_string(),
@@ -198,10 +189,6 @@ mod tests {
             assert_eq!(hv.memory_info.default_memory, 100);
             assert!(!hv.enable_iothreads);
             assert_eq!(hv.indep_iothreads, 3);
-            assert_eq!(
-                hv.memory_info.file_mem_backend,
-                "./test_file_backend_mem_root"
-            );
             assert!(!hv.memory_info.enable_hugepages);
             assert_eq!(hv.jailer_path, "./test_jailer_path".to_string());
             assert_eq!(hv.boot_info.kernel, "./test_kernel_path");
@@ -242,11 +229,6 @@ mod tests {
             .output()
             .expect("failed to execute process");
 
-        std::process::Command::new("rmdir")
-            .arg("./test_file_backend_mem_root")
-            .output()
-            .expect("failed to execute process");
-
         std::process::Command::new("rmdir")
             .arg("./test_jailer_path")
             .output()

src/libs/kata-types/tests/texture/configuration-anno-0.toml

@@ -19,7 +19,7 @@ default_maxvcpus = 64
 machine_type = "q35"
 confidential_guest = true
 rootless = true
-enable_annotations = ["shared_fs","path", "ctlpath","jailer_path","enable_iothreads","indep_iothreads","default_memory","memory_slots","enable_mem_prealloc","enable_hugepages","file_mem_backend","enable_virtio_mem","enable_guest_swap","default_vcpus","virtio_fs_extra_args","block_device_driver","vhost_user_store_path","kernel","guest_hook_path","block_device_cache_noflush","virtio_fs_daemon","blk_logical_sector_size","blk_physical_sector_size"]
+enable_annotations = ["shared_fs","path", "ctlpath","jailer_path","enable_iothreads","indep_iothreads","default_memory","memory_slots","enable_mem_prealloc","enable_hugepages","enable_virtio_mem","enable_guest_swap","default_vcpus","virtio_fs_extra_args","block_device_driver","vhost_user_store_path","kernel","guest_hook_path","block_device_cache_noflush","virtio_fs_daemon","blk_logical_sector_size","blk_physical_sector_size"]
 machine_accelerators="noapic"
 default_bridges = 2
 default_memory = 128
@@ -44,8 +44,6 @@ vhost_user_store_path = "/tmp"
 valid_vhost_user_store_paths = ["/var/kata/vhost-user-store*", "/tmp/kata?","/var/tmp","./store_path"]
 enable_iommu = true
 enable_iommu_platform = true
-file_mem_backend = "/dev/shm"
-valid_file_mem_backends = ["/dev/shm","/dev/snd","./test_file_backend_mem_root"]
 pflashes = ["/proc/mounts"]
 enable_debug = true
 disable_image_nvdimm = true
@@ -85,5 +83,3 @@ enable_pprof = true
 name="virt-container"
 hypervisor_name = "qemu"
 agent_name = "agent0"
-
-

src/libs/kata-types/tests/texture/configuration-anno-1.toml

@@ -43,8 +43,6 @@ vhost_user_store_path = "/tmp"
 valid_vhost_user_store_paths = ["/var/kata/vhost-user-store*", "/tmp/kata?"]
 enable_iommu = true
 enable_iommu_platform = true
-file_mem_backend = "/dev/shm"
-valid_file_mem_backends = ["/dev/shm"]
 pflashes = ["/proc/mounts"]
 enable_debug = true
 disable_image_nvdimm = true
@@ -84,4 +82,3 @@ enable_pprof = true
 name="virt-container"
 hypervisor_name = "qemu"
 agent_name = "agent0"
-

src/runtime-rs/Makefile

@@ -208,8 +208,6 @@ DEFINDEPIOTHREADS := 0
 DEFENABLEVHOSTUSERSTORE := false
 DEFVHOSTUSERSTOREPATH := $(PKGRUNDIR)/vhost-user
 DEFVALIDVHOSTUSERSTOREPATHS := [\"$(DEFVHOSTUSERSTOREPATH)\"]
-DEFFILEMEMBACKEND := ""
-DEFVALIDFILEMEMBACKENDS := [\"$(DEFFILEMEMBACKEND)\"]
 DEFMSIZE9P := 8192
 DEFVFIOMODE := guest-kernel
 DEFBINDMOUNTS := []
@@ -716,8 +714,6 @@ USER_VARS += DEFSECCOMPSANDBOXPARAM
 USER_VARS += DEFENABLEVHOSTUSERSTORE
 USER_VARS += DEFVHOSTUSERSTOREPATH
 USER_VARS += DEFVALIDVHOSTUSERSTOREPATHS
-USER_VARS += DEFFILEMEMBACKEND
-USER_VARS += DEFVALIDFILEMEMBACKENDS
 USER_VARS += DEFMSIZE9P
 USER_VARS += DEFENTROPYSOURCE
 USER_VARS += DEFVALIDENTROPYSOURCES

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

@@ -327,17 +327,6 @@ enable_iommu_platform = false
 # Your distribution recommends: @DEFVALIDVHOSTUSERSTOREPATHS@
 valid_vhost_user_store_paths = @DEFVALIDVHOSTUSERSTOREPATHS@
 
-# Enable file based guest memory support. The default is an empty string which
-# will disable this feature. In the case of virtio-fs, this is enabled
-# automatically and '/dev/shm' is used as the backing folder.
-# This option will be ignored if VM templating is enabled.
-file_mem_backend = "@DEFFILEMEMBACKEND@"
-
-# List of valid annotations values for the file_mem_backend annotation
-# The default if not set is empty (all annotations rejected.)
-# Your distribution recommends: @DEFVALIDFILEMEMBACKENDS@
-valid_file_mem_backends = @DEFVALIDFILEMEMBACKENDS@
-
 # -pflash can add image file to VM. The arguments of it should be in format
 # of ["/path/to/flash0.img", "/path/to/flash1.img"]
 pflashes = []

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

@@ -326,17 +326,6 @@ valid_vhost_user_store_paths = @DEFVALIDVHOSTUSERSTOREPATHS@
 # Zero disables reconnecting, and the default is zero.
 vhost_user_reconnect_timeout_sec = 0
 
-# Enable file based guest memory support. The default is an empty string which
-# will disable this feature. In the case of virtio-fs, this is enabled
-# automatically and '/dev/shm' is used as the backing folder.
-# This option will be ignored if VM templating is enabled.
-file_mem_backend = "@DEFFILEMEMBACKEND@"
-
-# List of valid annotations values for the file_mem_backend annotation
-# The default if not set is empty (all annotations rejected.)
-# Your distribution recommends: @DEFVALIDFILEMEMBACKENDS@
-valid_file_mem_backends = @DEFVALIDFILEMEMBACKENDS@
-
 # -pflash can add image file to VM. The arguments of it should be in format
 # of ["/path/to/flash0.img", "/path/to/flash1.img"]
 pflashes = []

src/runtime-rs/config/configuration-qemu-nvidia-gpu-snp-runtime-rs.toml.in

@@ -367,17 +367,6 @@ valid_vhost_user_store_paths = @DEFVALIDVHOSTUSERSTOREPATHS@
 # Zero disables reconnecting, and the default is zero.
 vhost_user_reconnect_timeout_sec = 0
 
-# Enable file based guest memory support. The default is an empty string which
-# will disable this feature. In the case of virtio-fs, this is enabled
-# automatically and '/dev/shm' is used as the backing folder.
-# This option will be ignored if VM templating is enabled.
-file_mem_backend = "@DEFFILEMEMBACKEND@"
-
-# List of valid annotations values for the file_mem_backend annotation
-# The default if not set is empty (all annotations rejected.)
-# Your distribution recommends: @DEFVALIDFILEMEMBACKENDS@
-valid_file_mem_backends = @DEFVALIDFILEMEMBACKENDS@
-
 # -pflash can add image file to VM. The arguments of it should be in format
 # of ["/path/to/flash0.img", "/path/to/flash1.img"]
 pflashes = []

src/runtime-rs/config/configuration-qemu-nvidia-gpu-tdx-runtime-rs.toml.in

@@ -343,17 +343,6 @@ valid_vhost_user_store_paths = @DEFVALIDVHOSTUSERSTOREPATHS@
 # Zero disables reconnecting, and the default is zero.
 vhost_user_reconnect_timeout_sec = 0
 
-# Enable file based guest memory support. The default is an empty string which
-# will disable this feature. In the case of virtio-fs, this is enabled
-# automatically and '/dev/shm' is used as the backing folder.
-# This option will be ignored if VM templating is enabled.
-file_mem_backend = "@DEFFILEMEMBACKEND@"
-
-# List of valid annotations values for the file_mem_backend annotation
-# The default if not set is empty (all annotations rejected.)
-# Your distribution recommends: @DEFVALIDFILEMEMBACKENDS@
-valid_file_mem_backends = @DEFVALIDFILEMEMBACKENDS@
-
 # -pflash can add image file to VM. The arguments of it should be in format
 # of ["/path/to/flash0.img", "/path/to/flash1.img"]
 pflashes = []

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

@@ -318,17 +318,6 @@ enable_iommu_platform = false
 # Your distribution recommends: @DEFVALIDVHOSTUSERSTOREPATHS@
 valid_vhost_user_store_paths = @DEFVALIDVHOSTUSERSTOREPATHS@
 
-# Enable file based guest memory support. The default is an empty string which
-# will disable this feature. In the case of virtio-fs, this is enabled
-# automatically and '/dev/shm' is used as the backing folder.
-# This option will be ignored if VM templating is enabled.
-file_mem_backend = "@DEFFILEMEMBACKEND@"
-
-# List of valid annotations values for the file_mem_backend annotation
-# The default if not set is empty (all annotations rejected.)
-# Your distribution recommends: @DEFVALIDFILEMEMBACKENDS@
-valid_file_mem_backends = @DEFVALIDFILEMEMBACKENDS@
-
 # -pflash can add image file to VM. The arguments of it should be in format
 # of ["/path/to/flash0.img", "/path/to/flash1.img"]
 pflashes = []

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

@@ -317,17 +317,6 @@ enable_iommu_platform = false
 # Your distribution recommends: @DEFVALIDVHOSTUSERSTOREPATHS@
 valid_vhost_user_store_paths = @DEFVALIDVHOSTUSERSTOREPATHS@
 
-# Enable file based guest memory support. The default is an empty string which
-# will disable this feature. In the case of virtio-fs, this is enabled
-# automatically and '/dev/shm' is used as the backing folder.
-# This option will be ignored if VM templating is enabled.
-file_mem_backend = "@DEFFILEMEMBACKEND@"
-
-# List of valid annotations values for the file_mem_backend annotation
-# The default if not set is empty (all annotations rejected.)
-# Your distribution recommends: @DEFVALIDFILEMEMBACKENDS@
-valid_file_mem_backends = @DEFVALIDFILEMEMBACKENDS@
-
 # -pflash can add image file to VM. The arguments of it should be in format
 # of ["/path/to/flash0.img", "/path/to/flash1.img"]
 pflashes = []

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

@@ -358,17 +358,6 @@ enable_iommu_platform = false
 # Your distribution recommends: @DEFVALIDVHOSTUSERSTOREPATHS@
 valid_vhost_user_store_paths = @DEFVALIDVHOSTUSERSTOREPATHS@
 
-# Enable file based guest memory support. The default is an empty string which
-# will disable this feature. In the case of virtio-fs, this is enabled
-# automatically and '/dev/shm' is used as the backing folder.
-# This option will be ignored if VM templating is enabled.
-file_mem_backend = ""
-
-# List of valid annotations values for the file_mem_backend annotation
-# The default if not set is empty (all annotations rejected.)
-# Your distribution recommends: @DEFVALIDFILEMEMBACKENDS@
-valid_file_mem_backends = @DEFVALIDFILEMEMBACKENDS@
-
 # -pflash can add image file to VM. The arguments of it should be in format
 # of ["/path/to/flash0.img", "/path/to/flash1.img"]
 pflashes = []

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

@@ -335,17 +335,6 @@ enable_iommu_platform = false
 # Your distribution recommends: @DEFVALIDVHOSTUSERSTOREPATHS@
 valid_vhost_user_store_paths = @DEFVALIDVHOSTUSERSTOREPATHS@
 
-# Enable file based guest memory support. The default is an empty string which
-# will disable this feature. In the case of virtio-fs, this is enabled
-# automatically and '/dev/shm' is used as the backing folder.
-# This option will be ignored if VM templating is enabled.
-file_mem_backend = "@DEFFILEMEMBACKEND@"
-
-# List of valid annotations values for the file_mem_backend annotation
-# The default if not set is empty (all annotations rejected.)
-# Your distribution recommends: @DEFVALIDFILEMEMBACKENDS@
-valid_file_mem_backends = @DEFVALIDFILEMEMBACKENDS@
-
 # -pflash can add image file to VM. The arguments of it should be in format
 # of ["/path/to/flash0.img", "/path/to/flash1.img"]
 pflashes = []

src/runtime-rs/tests/texture/configuration-qemu.toml

@@ -19,7 +19,7 @@ default_maxvcpus = 64
 machine_type = "q35"
 confidential_guest = true
 rootless = true
-enable_annotations = ["shared_fs","path", "ctlpath","jailer_path","enable_iothreads","default_memory","memory_slots","enable_mem_prealloc","enable_hugepages","file_mem_backend","enable_virtio_mem","enable_guest_swap","default_vcpus","virtio_fs_extra_args","block_device_driver","vhost_user_store_path","kernel","guest_hook_path","block_device_cache_noflush","virtio_fs_daemon"]
+enable_annotations = ["shared_fs","path", "ctlpath","jailer_path","enable_iothreads","default_memory","memory_slots","enable_mem_prealloc","enable_hugepages","enable_virtio_mem","enable_guest_swap","default_vcpus","virtio_fs_extra_args","block_device_driver","vhost_user_store_path","kernel","guest_hook_path","block_device_cache_noflush","virtio_fs_daemon"]
 machine_accelerators="noapic"
 default_bridges = 2
 default_memory = 128
@@ -44,8 +44,6 @@ vhost_user_store_path = "/tmp"
 valid_vhost_user_store_paths = ["/var/kata/vhost-user-store*", "/tmp/kata?","/var/tmp","./store_path"]
 enable_iommu = true
 enable_iommu_platform = true
-file_mem_backend = "/dev/shm"
-valid_file_mem_backends = ["/dev/shm","/dev/snd","./test_file_backend_mem_root"]
 pflashes = ["/proc/mounts"]
 enable_debug = true
 msize_9p = 16384
@@ -87,4 +85,3 @@ enable_pprof = true
 hypervisor_name = "qemu"
 agent_name = "agent0"
 
-