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limayaml: remove implementation details of QEMU #4205

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Merged
merged 1 commit into from
Oct 15, 2025
Merged

limayaml: remove implementation details of QEMU #4205

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45 changes: 43 additions & 2 deletions pkg/driver/qemu/qemu.go
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Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,7 @@ import (
"slices"
"strconv"
"strings"
"sync"
"time"

"github.com/coreos/go-semver/semver"
Expand Down Expand Up @@ -427,8 +428,8 @@ func defaultCPUType() limatype.CPUType {
limatype.S390X: "max",
}
for arch := range cpuType {
if limayaml.IsNativeArch(arch) && limayaml.IsAccelOS() {
if limayaml.HasHostCPU() {
if limayaml.IsNativeArch(arch) && Accel(arch) != "tcg" {
if hasHostCPU() {
cpuType[arch] = "host"
}
}
Expand Down Expand Up @@ -1272,3 +1273,43 @@ func getFirmwareVars(qemuExe string, arch limatype.Arch) (string, error) {

return "", fmt.Errorf("could not find firmware vars for %q", arch)
}

var hasSMEDarwin = sync.OnceValue(func() bool {
if runtime.GOOS != "darwin" || runtime.GOARCH != "arm64" {
return false
}
// golang.org/x/sys/cpu does not support inspecting the availability of SME yet
s, err := osutil.Sysctl(context.Background(), "hw.optional.arm.FEAT_SME")
if err != nil {
logrus.WithError(err).Debug("failed to check hw.optional.arm.FEAT_SME")
}
return s == "1"
})

func hasHostCPU() bool {
switch runtime.GOOS {
case "darwin":
if hasSMEDarwin() {
// [2025-02-05]
// SME is available since Apple M4 running macOS 15.2, but it was broken on macOS 15.2.
// It has been fixed in 15.3.
//
// https://github.com/lima-vm/lima/issues/3032
// https://gitlab.com/qemu-project/qemu/-/issues/2665
// https://gitlab.com/qemu-project/qemu/-/issues/2721

// [2025-02-12]
// SME got broken again after upgrading QEMU from 9.2.0 to 9.2.1 (Homebrew bottle).
// Possibly this regression happened in some build process rather than in QEMU itself?
// https://github.com/lima-vm/lima/issues/3226
return false
}
return true
case "linux":
return true
case "netbsd", "windows":
return false
}
// Not reached
return false
}
51 changes: 0 additions & 51 deletions pkg/limayaml/defaults.go
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Original file line number Diff line number Diff line change
Expand Up @@ -19,7 +19,6 @@ import (
"slices"
"strconv"
"strings"
"sync"
"text/template"

"github.com/docker/go-units"
Expand Down Expand Up @@ -974,56 +973,6 @@ func ResolveArch(s *string) limatype.Arch {
return *s
}

func IsAccelOS() bool {
switch runtime.GOOS {
case "darwin", "linux", "netbsd", "windows", "dragonfly":
// Accelerator
return true
}
// Using TCG
return false
}

var hasSMEDarwin = sync.OnceValue(func() bool {
if runtime.GOOS != "darwin" || runtime.GOARCH != "arm64" {
return false
}
// golang.org/x/sys/cpu does not support inspecting the availability of SME yet
s, err := osutil.Sysctl(context.Background(), "hw.optional.arm.FEAT_SME")
if err != nil {
logrus.WithError(err).Debug("failed to check hw.optional.arm.FEAT_SME")
}
return s == "1"
})

func HasHostCPU() bool {
switch runtime.GOOS {
case "darwin":
if hasSMEDarwin() {
// [2025-02-05]
// SME is available since Apple M4 running macOS 15.2, but it was broken on macOS 15.2.
// It has been fixed in 15.3.
//
// https://github.com/lima-vm/lima/issues/3032
// https://gitlab.com/qemu-project/qemu/-/issues/2665
// https://gitlab.com/qemu-project/qemu/-/issues/2721

// [2025-02-12]
// SME got broken again after upgrading QEMU from 9.2.0 to 9.2.1 (Homebrew bottle).
// Possibly this regression happened in some build process rather than in QEMU itself?
// https://github.com/lima-vm/lima/issues/3226
return false
}
return true
case "linux":
return true
case "netbsd", "windows":
return false
}
// Not reached
return false
}

func IsNativeArch(arch limatype.Arch) bool {
nativeX8664 := arch == limatype.X8664 && runtime.GOARCH == "amd64"
nativeAARCH64 := arch == limatype.AARCH64 && runtime.GOARCH == "arm64"
Expand Down
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