Move huge pages support out of developer preview.

docs/hugepages.md

@@ -1,10 +1,5 @@
 # Backing Guest Memory by Huge Pages
 
-> [!WARNING]
->
-> Support is currently in **developer preview**. See
-> [this section](RELEASE_POLICY.md#developer-preview-features) for more info.
-
 Firecracker supports backing the guest memory of a VM by 2MB hugetlbfs pages.
 This can be enabled by setting the `huge_pages` field of `PUT` or `PATCH`
 requests to the `/machine-config` endpoint to `2M`.
@@ -44,7 +39,6 @@ Currently, hugetlbfs support is mutually exclusive with the following
 Firecracker features:
 
 - Memory Ballooning via the [Balloon Device](./ballooning.md)
-- Initrd
 
 ## FAQ
 

src/vmm/src/resources.rs

@@ -9,7 +9,7 @@ use serde::{Deserialize, Serialize};
 
 use crate::cpu_config::templates::CustomCpuTemplate;
 use crate::device_manager::persist::SharedDeviceType;
-use crate::logger::{info, log_dev_preview_warning};
+use crate::logger::info;
 use crate::mmds;
 use crate::mmds::data_store::{Mmds, MmdsVersion};
 use crate::mmds::ns::MmdsNetworkStack;
@@ -246,10 +246,6 @@ impl VmResources {
         &mut self,
         update: &MachineConfigUpdate,
     ) -> Result<(), MachineConfigError> {
-        if update.huge_pages.is_some() && update.huge_pages != Some(HugePageConfig::None) {
-            log_dev_preview_warning("Huge pages support", None);
-        }
-
         let updated = self.machine_config.update(update)?;
 
         // The VM cannot have a memory size smaller than the target size
@@ -268,13 +264,6 @@ impl VmResources {
         if self.balloon.get().is_some() && updated.huge_pages != HugePageConfig::None {
             return Err(MachineConfigError::BalloonAndHugePages);
         }
-
-        if self.boot_source.config.initrd_path.is_some()
-            && updated.huge_pages != HugePageConfig::None
-        {
-            return Err(MachineConfigError::InitrdAndHugePages);
-        }
-
         self.machine_config = updated;
 
         Ok(())
@@ -341,12 +330,6 @@ impl VmResources {
         &mut self,
         boot_source_cfg: BootSourceConfig,
     ) -> Result<(), BootSourceConfigError> {
-        if boot_source_cfg.initrd_path.is_some()
-            && self.machine_config.huge_pages != HugePageConfig::None
-        {
-            return Err(BootSourceConfigError::HugePagesAndInitRd);
-        }
-
         self.boot_source = BootSource {
             builder: Some(BootConfig::new(&boot_source_cfg)?),
             config: boot_source_cfg,

src/vmm/src/vmm_config/boot_source.rs

@@ -42,8 +42,6 @@ pub enum BootSourceConfigError {
     InvalidInitrdPath(io::Error),
     /// The kernel command line is invalid: {0}
     InvalidKernelCommandLine(String),
-    /// Firecracker's huge pages support is incompatible with initrds.
-    HugePagesAndInitRd,
 }
 
 /// Holds the kernel specification (both configuration as well as runtime details).

src/vmm/src/vmm_config/machine_config.rs

@@ -31,8 +31,6 @@ pub enum MachineConfigError {
     KernelVersion,
     /// Firecracker's huge pages support is incompatible with memory ballooning.
     BalloonAndHugePages,
-    /// Firecracker's huge pages support is incompatible with initrds.
-    InitrdAndHugePages,
 }
 
 /// Describes the possible (huge)page configurations for a microVM's memory.

tests/conftest.py

@@ -498,20 +498,6 @@ def uvm_plain_debug(microvm_factory, guest_kernel_6_1_debug, rootfs_rw):
     return microvm_factory.build(guest_kernel_6_1_debug, rootfs_rw)
 
 
-@pytest.fixture
-def uvm_with_initrd(
-    microvm_factory, guest_kernel_linux_5_10, record_property, artifact_dir
-):
-    """
-    See file:../docs/initrd.md
-    """
-    fs = artifact_dir / "initramfs.cpio"
-    record_property("rootfs", fs.name)
-    uvm = microvm_factory.build(guest_kernel_linux_5_10)
-    uvm.initrd_file = fs
-    yield uvm
-
-
 @pytest.fixture
 def vcpu_count():
     """Return default vcpu_count. Use indirect parametrization to override."""

tests/integration_tests/performance/test_huge_pages.py

@@ -251,41 +251,3 @@ def test_negative_huge_pages_plus_balloon(uvm_plain):
         match="Machine config error: Firecracker's huge pages support is incompatible with memory ballooning.",
     ):
         uvm_plain.basic_config(huge_pages=HugePagesConfig.HUGETLBFS_2MB)
-
-
-def test_negative_huge_pages_plus_initrd(uvm_with_initrd):
-    """Tests that huge pages and initrd cannot be used together"""
-    uvm_with_initrd.jailer.daemonize = False
-    uvm_with_initrd.spawn()
-    uvm_with_initrd.memory_monitor = None
-
-    # Ensure setting huge pages and then telling FC to boot an initrd does not work
-    with pytest.raises(
-        RuntimeError,
-        match="Boot source error: Firecracker's huge pages support is incompatible with initrds.",
-    ):
-        # `basic_config` first does a PUT to /machine-config, which will apply the huge pages configuration,
-        # and then a PUT to /boot-source, which will register the initrd
-        uvm_with_initrd.basic_config(
-            boot_args="console=ttyS0 reboot=k panic=1 pci=off",
-            use_initrd=True,
-            huge_pages=HugePagesConfig.HUGETLBFS_2MB,
-            add_root_device=False,
-            vcpu_count=1,
-        )
-
-    # Ensure telling FC about the initrd first and then setting huge pages doesn't work
-    # This first does a PUT to /machine-config to reset the huge pages configuration, before doing a
-    # PUT to /boot-source to register the initrd
-    uvm_with_initrd.basic_config(
-        huge_pages=HugePagesConfig.NONE,
-        boot_args="console=ttyS0 reboot=k panic=1 pci=off",
-        use_initrd=True,
-    )
-    with pytest.raises(
-        RuntimeError,
-        match="Machine config error: Firecracker's huge pages support is incompatible with initrds.",
-    ):
-        uvm_with_initrd.api.machine_config.patch(
-            huge_pages=HugePagesConfig.HUGETLBFS_2MB
-        )

tests/integration_tests/functional/test_initrd.py → tests/integration_tests/performance/test_initrd.py

@@ -1,13 +1,27 @@
 # Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 # SPDX-License-Identifier: Apache-2.0
 """Tests for initrd."""
+import pytest
 
-from framework.microvm import Serial
+from framework.microvm import HugePagesConfig, Serial
 
 INITRD_FILESYSTEM = "rootfs"
 
 
-def test_microvm_initrd_with_serial(uvm_with_initrd):
+@pytest.fixture
+def uvm_with_initrd(microvm_factory, guest_kernel, record_property, artifact_dir):
+    """
+    See file:../docs/initrd.md
+    """
+    fs = artifact_dir / "initramfs.cpio"
+    record_property("rootfs", fs.name)
+    uvm = microvm_factory.build(guest_kernel)
+    uvm.initrd_file = fs
+    yield uvm
+
+
+@pytest.mark.parametrize("huge_pages", HugePagesConfig)
+def test_microvm_initrd_with_serial(uvm_with_initrd, huge_pages):
     """
     Test that a boot using initrd successfully loads the root filesystem.
     """
@@ -21,6 +35,7 @@ def test_microvm_initrd_with_serial(uvm_with_initrd):
         vcpu_count=1,
         boot_args="console=ttyS0 reboot=k panic=1 pci=off",
         use_initrd=True,
+        huge_pages=huge_pages,
     )
 
     vm.start()