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Re: [PATCH] target/i386: Fix cpuid level for AMD
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [PATCH] target/i386: Fix cpuid level for AMD |
Date: |
Tue, 29 Jun 2021 15:06:02 +0100 |
User-agent: |
Mutt/2.0.7 (2021-05-04) |
* zhenwei pi (pizhenwei@bytedance.com) wrote:
> A AMD server typically has cpuid level 0x10(test on Rome/Milan), it
> should not be changed to 0x1f in multi-dies case.
>
> Fixes: a94e1428991 (target/i386: Add CPUID.1F generation support
> for multi-dies PCMachine)
> Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
(Copying in Babu)
Hmm I think you're right. I've cc'd in Babu and Wei.
Eduardo: What do we need to do about compatibility, do we need to wire
this to machine type or CPU version?
Dave
> ---
> target/i386/cpu.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index a9fe1662d3..3934c559e4 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -5961,8 +5961,12 @@ void x86_cpu_expand_features(X86CPU *cpu, Error **errp)
> }
> }
>
> - /* CPU topology with multi-dies support requires CPUID[0x1F] */
> - if (env->nr_dies > 1) {
> + /*
> + * Intel CPU topology with multi-dies support requires CPUID[0x1F].
> + * For AMD Rome/Milan, cpuid level is 0x10, and guest OS should
> detect
> + * extended toplogy by leaf 0xB. Only adjust it for Intel CPU.
> + */
> + if ((env->nr_dies > 1) && IS_INTEL_CPU(env)) {
> x86_cpu_adjust_level(cpu, &env->cpuid_min_level, 0x1F);
> }
>
> --
> 2.25.1
>
>
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK