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Merged
ZR233 merged 1 commit into from
Jun 11, 2026
Merged

feat(axbuild): enable x86 kvm acceleration #1221

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5 changes: 4 additions & 1 deletion scripts/axbuild/src/context/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -142,10 +142,13 @@ impl AppContext {
&mut self,
cargo: Cargo,
build_config_path: PathBuf,
qemu: Option<QemuConfig>,
mut qemu: Option<QemuConfig>,
) -> anyhow::Result<()> {
let _env_guard = EnvRestoreGuard::set(&cargo.env);
let _path_guard = self.scoped_qemu_path(&cargo)?;
if let Some(qemu) = qemu.as_mut() {
crate::test::qemu::apply_x86_64_kvm_accel_if_available(qemu, &cargo);
}
self.set_build_config_path(build_config_path);
let build_config_path = self.build_config_path.clone();
ostool_build::cargo_run(
Expand Down
169 changes: 153 additions & 16 deletions scripts/axbuild/src/test/qemu.rs
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -998,6 +998,16 @@ enum DynamicPlatformBootArch {
}

pub(crate) fn apply_dynamic_platform_qemu_boot(qemu: &mut QemuConfig, cargo: &Cargo) {
apply_dynamic_platform_qemu_boot_with_kvm_probe(qemu, cargo, host_kvm_available);
}

fn apply_dynamic_platform_qemu_boot_with_kvm_probe(
qemu: &mut QemuConfig,
cargo: &Cargo,
kvm_available: impl FnOnce() -> bool,
) {
apply_x86_64_kvm_accel_if_available_with_probe(qemu, cargo, kvm_available);

let Some(arch) = cargo_dynamic_platform_boot_arch(cargo) else {
return;
};
Expand All @@ -1018,6 +1028,45 @@ pub(crate) fn apply_dynamic_platform_qemu_boot(qemu: &mut QemuConfig, cargo: &Ca
apply_dynamic_x86_64_qemu_debug_args(qemu);
}

pub(crate) fn apply_x86_64_kvm_accel_if_available(qemu: &mut QemuConfig, cargo: &Cargo) {
apply_x86_64_kvm_accel_if_available_with_probe(qemu, cargo, host_kvm_available);
}

fn apply_x86_64_kvm_accel_if_available_with_probe(
qemu: &mut QemuConfig,
cargo: &Cargo,
kvm_available: impl FnOnce() -> bool,
) {
if !cargo_target_is_x86_64(&cargo.target) {
return;
}
if qemu.args.iter().any(|arg| arg == "-accel") {
return;
}
if !kvm_available() {
return;
}

qemu.args.push("-accel".to_string());
qemu.args.push("kvm".to_string());
}

#[cfg(unix)]
fn host_kvm_available() -> bool {
use std::fs::OpenOptions;

OpenOptions::new()
.read(true)
.write(true)
.open("/dev/kvm")
.is_ok()
}

#[cfg(not(unix))]
fn host_kvm_available() -> bool {
false
}

fn apply_dynamic_x86_64_qemu_debug_args(qemu: &mut QemuConfig) {
let Ok(value) = std::env::var(DYNAMIC_X86_64_QEMU_DEBUG_ENV) else {
return;
Expand Down Expand Up @@ -1200,6 +1249,10 @@ fn cargo_dynamic_platform_boot_arch(cargo: &Cargo) -> Option<DynamicPlatformBoot
}

fn cargo_target_is_dynamic_x86_64(target: &str) -> bool {
cargo_target_is_x86_64(target)
}

fn cargo_target_is_x86_64(target: &str) -> bool {
let target = target.strip_suffix(".json").unwrap_or(target);
target.ends_with("x86_64-unknown-none") || target.ends_with("x86_64-unknown-linux-musl")
}
Expand Down Expand Up @@ -1598,7 +1651,7 @@ mod tests {
..Default::default()
};

apply_dynamic_platform_qemu_boot(&mut qemu, &cargo);
apply_dynamic_platform_qemu_boot_with_kvm_probe(&mut qemu, &cargo, || false);

assert!(qemu.uefi);
assert!(qemu.to_bin);
Expand All @@ -1620,7 +1673,7 @@ mod tests {
..Default::default()
};

apply_dynamic_platform_qemu_boot(&mut qemu, &cargo);
apply_dynamic_platform_qemu_boot_with_kvm_probe(&mut qemu, &cargo, || false);

assert!(qemu.uefi);
assert!(qemu.to_bin);
Expand Down Expand Up @@ -1648,7 +1701,7 @@ mod tests {
..Default::default()
};

apply_dynamic_platform_qemu_boot(&mut qemu, &cargo);
apply_dynamic_platform_qemu_boot_with_kvm_probe(&mut qemu, &cargo, || false);

assert_eq!(
qemu.args,
Expand Down Expand Up @@ -1682,7 +1735,7 @@ mod tests {
..Default::default()
};

apply_dynamic_platform_qemu_boot(&mut qemu, &cargo);
apply_dynamic_platform_qemu_boot_with_kvm_probe(&mut qemu, &cargo, || false);

assert!(qemu.uefi);
assert!(qemu.to_bin);
Expand All @@ -1704,7 +1757,7 @@ mod tests {
..Default::default()
};

apply_dynamic_platform_qemu_boot(&mut qemu, &cargo);
apply_dynamic_platform_qemu_boot_with_kvm_probe(&mut qemu, &cargo, || false);

assert!(qemu.uefi);
assert!(qemu.to_bin);
Expand All @@ -1731,7 +1784,7 @@ mod tests {
..Default::default()
};

apply_dynamic_platform_qemu_boot(&mut qemu, &cargo);
apply_dynamic_platform_qemu_boot_with_kvm_probe(&mut qemu, &cargo, || false);

assert_eq!(
qemu.args,
Expand Down Expand Up @@ -1762,7 +1815,7 @@ mod tests {
..Default::default()
};

apply_dynamic_platform_qemu_boot(&mut qemu, &cargo);
apply_dynamic_platform_qemu_boot_with_kvm_probe(&mut qemu, &cargo, || false);

assert_eq!(
qemu.args,
Expand All @@ -1789,7 +1842,7 @@ mod tests {
..Default::default()
};

apply_dynamic_platform_qemu_boot(&mut qemu, &cargo);
apply_dynamic_platform_qemu_boot_with_kvm_probe(&mut qemu, &cargo, || false);

assert_eq!(
qemu.args,
Expand Down Expand Up @@ -1817,8 +1870,8 @@ mod tests {
..Default::default()
};

apply_dynamic_platform_qemu_boot(&mut qemu, &cargo);
apply_dynamic_platform_qemu_boot(&mut qemu, &cargo);
apply_dynamic_platform_qemu_boot_with_kvm_probe(&mut qemu, &cargo, || false);
apply_dynamic_platform_qemu_boot_with_kvm_probe(&mut qemu, &cargo, || false);

assert_eq!(
qemu.args,
Expand Down Expand Up @@ -1850,8 +1903,8 @@ mod tests {
..Default::default()
};

apply_dynamic_platform_qemu_boot(&mut qemu, &cargo);
apply_dynamic_platform_qemu_boot(&mut qemu, &cargo);
apply_dynamic_platform_qemu_boot_with_kvm_probe(&mut qemu, &cargo, || false);
apply_dynamic_platform_qemu_boot_with_kvm_probe(&mut qemu, &cargo, || false);

assert_eq!(
qemu.args,
Expand Down Expand Up @@ -1888,7 +1941,7 @@ mod tests {
..Default::default()
};

apply_dynamic_platform_qemu_boot(&mut qemu, &cargo);
apply_dynamic_platform_qemu_boot_with_kvm_probe(&mut qemu, &cargo, || false);

assert_eq!(
qemu.args,
Expand Down Expand Up @@ -1918,7 +1971,7 @@ mod tests {
..Default::default()
};

apply_dynamic_platform_qemu_boot(&mut qemu, &cargo);
apply_dynamic_platform_qemu_boot_with_kvm_probe(&mut qemu, &cargo, || false);

assert_eq!(
qemu.args,
Expand Down Expand Up @@ -1951,7 +2004,7 @@ mod tests {
..Default::default()
};

apply_dynamic_platform_qemu_boot(&mut qemu, &cargo);
apply_dynamic_platform_qemu_boot_with_kvm_probe(&mut qemu, &cargo, || false);

assert!(!qemu.uefi);
assert!(!qemu.to_bin);
Expand All @@ -1974,13 +2027,97 @@ mod tests {
..Default::default()
};

apply_dynamic_platform_qemu_boot(&mut qemu, &cargo);
apply_dynamic_platform_qemu_boot_with_kvm_probe(&mut qemu, &cargo, || false);

assert!(!qemu.uefi);
assert!(!qemu.to_bin);
assert_eq!(qemu.args, ["-snapshot"]);
}

#[test]
fn x86_64_qemu_uses_kvm_when_available() {
let cargo = Cargo {
target: "x86_64-unknown-none".to_string(),
..Default::default()
};
let mut qemu = QemuConfig {
args: vec!["-nographic".to_string()],
..Default::default()
};

apply_x86_64_kvm_accel_if_available_with_probe(&mut qemu, &cargo, || true);

assert_eq!(qemu.args, ["-nographic", "-accel", "kvm"]);
}

#[test]
fn qemu_boot_rewrite_uses_kvm_for_x86_64_when_available() {
let cargo = Cargo {
target: "scripts/targets/std/x86_64-unknown-linux-musl.json".to_string(),
..Default::default()
};
let mut qemu = QemuConfig {
args: vec!["-nographic".to_string()],
..Default::default()
};

apply_dynamic_platform_qemu_boot_with_kvm_probe(&mut qemu, &cargo, || true);

assert_eq!(qemu.args, ["-nographic", "-accel", "kvm"]);
}

#[test]
fn x86_64_qemu_keeps_explicit_accel() {
let cargo = Cargo {
target: "x86_64-unknown-none".to_string(),
..Default::default()
};
let mut qemu = QemuConfig {
args: vec![
"-nographic".to_string(),
"-accel".to_string(),
"tcg,thread=single".to_string(),
],
..Default::default()
};

apply_x86_64_kvm_accel_if_available_with_probe(&mut qemu, &cargo, || true);

assert_eq!(qemu.args, ["-nographic", "-accel", "tcg,thread=single"]);
}

#[test]
fn non_x86_64_qemu_does_not_use_kvm() {
let cargo = Cargo {
target: "riscv64gc-unknown-none-elf".to_string(),
..Default::default()
};
let mut qemu = QemuConfig {
args: vec!["-nographic".to_string()],
..Default::default()
};

apply_x86_64_kvm_accel_if_available_with_probe(&mut qemu, &cargo, || true);

assert_eq!(qemu.args, ["-nographic"]);
}

#[test]
fn x86_64_qemu_does_not_use_kvm_without_permission() {
let cargo = Cargo {
target: "x86_64-unknown-none".to_string(),
..Default::default()
};
let mut qemu = QemuConfig {
args: vec!["-nographic".to_string()],
..Default::default()
};

apply_x86_64_kvm_accel_if_available_with_probe(&mut qemu, &cargo, || false);

assert_eq!(qemu.args, ["-nographic"]);
}

#[test]
fn qemu_failure_summary_is_aggregated() {
let mut summary = QemuTestSummary::default();
Expand Down