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Re: [Qemu-devel] [PATCH] Revert "i386: correct cpu_x86_cpuid(0xd)"
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH] Revert "i386: correct cpu_x86_cpuid(0xd)" |
Date: |
Mon, 19 Aug 2019 15:34:00 +0100 |
User-agent: |
Mutt/1.12.1 (2019-06-15) |
Copying in Eduardo.
* Bingsong Si (address@hidden) wrote:
> This reverts commit de2e68c902f7b6e438b0fa3cfedd74a06a20704f.
>
> Initial value of env->xcr0 == 0, then CPUID(EAX=0xd,ECX=0).EBX == 0, after kvm
> upstream commit 412a3c41, It is ok.
> On host before commit 412a3c41, some legacy guest, i.e. CentOS 6, get
> xstate_size == 0, will crash the guest.
>
> Signed-off-by: Bingsong Si <address@hidden>
> ---
> target/i386/cpu.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index ff65e11008..69562e21ed 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -4416,7 +4416,7 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index,
> uint32_t count,
> *ecx = xsave_area_size(x86_cpu_xsave_components(cpu));
> *eax = env->features[FEAT_XSAVE_COMP_LO];
> *edx = env->features[FEAT_XSAVE_COMP_HI];
> - *ebx = xsave_area_size(env->xcr0);
> + *ebx = *ecx;
> } else if (count == 1) {
> *eax = env->features[FEAT_XSAVE];
> } else if (count < ARRAY_SIZE(x86_ext_save_areas)) {
> --
> 2.22.0
>
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK