On 10/21/2014 05:00 PM, Wei Huang wrote:
> No AMD CPUs support hyperthreading. When users select threads>1 in
> -smp option, QEMU fixes it by adjusting CPUID_0000_0001_EBX and
> CPUID_8000_0008_ECX based on inputs (sockets, cores, threads);
> so guest VM can boot correctly. However it is still better to gives
> users a warning when such case happens.
>
> Signed-off-by: Wei Huang <w...@redhat.com>
Tweaked as suggested by Eduardo, and applied.
Paolo
> ---
> target-i386/cpu.c | 23 ++++++++++++++++++++---
> 1 file changed, 20 insertions(+), 3 deletions(-)
>
> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> index e7bf9de..84cbbcd 100644
> --- a/target-i386/cpu.c
> +++ b/target-i386/cpu.c
> @@ -2696,6 +2696,10 @@ static void x86_cpu_apic_realize(X86CPU *cpu, Error
> **errp)
> }
> #endif
>
> +
> +#define IS_AMD_CPU(env) ((env)->cpuid_vendor1 == CPUID_VENDOR_AMD_1 && \
> + (env)->cpuid_vendor2 == CPUID_VENDOR_AMD_2 && \
> + (env)->cpuid_vendor3 == CPUID_VENDOR_AMD_3)
> static void x86_cpu_realizefn(DeviceState *dev, Error **errp)
> {
> CPUState *cs = CPU(dev);
> @@ -2703,6 +2707,7 @@ static void x86_cpu_realizefn(DeviceState *dev, Error
> **errp)
> X86CPUClass *xcc = X86_CPU_GET_CLASS(dev);
> CPUX86State *env = &cpu->env;
> Error *local_err = NULL;
> + static bool ht_warned;
>
> if (env->features[FEAT_7_0_EBX] && env->cpuid_level < 7) {
> env->cpuid_level = 7;
> @@ -2711,9 +2716,7 @@ static void x86_cpu_realizefn(DeviceState *dev, Error
> **errp)
> /* On AMD CPUs, some CPUID[8000_0001].EDX bits must match the bits on
> * CPUID[1].EDX.
> */
> - if (env->cpuid_vendor1 == CPUID_VENDOR_AMD_1 &&
> - env->cpuid_vendor2 == CPUID_VENDOR_AMD_2 &&
> - env->cpuid_vendor3 == CPUID_VENDOR_AMD_3) {
> + if (IS_AMD_CPU(env)) {
> env->features[FEAT_8000_0001_EDX] &= ~CPUID_EXT2_AMD_ALIASES;
> env->features[FEAT_8000_0001_EDX] |= (env->features[FEAT_1_EDX]
> & CPUID_EXT2_AMD_ALIASES);
> @@ -2742,6 +2745,20 @@ static void x86_cpu_realizefn(DeviceState *dev, Error
> **errp)
> mce_init(cpu);
> qemu_init_vcpu(cs);
>
> + /* AMD CPU doesn't support hyperthreading. Even though QEMU fixes
> + * this issue by adjusting CPUID_0000_0001_EBX and CPUID_8000_0008_ECX
> + * based on inputs (sockets,cores,threads), it is still better to gives
> + * users a warning.
> + *
> + * NOTE: the following code has to follow qemu_init_vcpu(). Otherwise
> + * cs->nr_threads hasn't be populated yet and the checking is incorrect.
> + */
> + if (IS_AMD_CPU(env) && (cs->nr_threads > 1) && !ht_warned) {
> + error_report("AMD CPU doesn't support hyperthreading. Please
> configure"
> + " -smp options properly.");
> + ht_warned = true;
> + }
> +
> x86_cpu_apic_realize(cpu, &local_err);
> if (local_err != NULL) {
> goto out;
>
