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From: Sean Christopherson <seanjc@google.com>
To: Jim Mattson <jmattson@google.com>
Cc: kvm@vger.kernel.org, pbonzini@redhat.com
Subject: Re: [PATCH 2/6] KVM: x86: Mask off reserved bits in CPUID.80000006H
Date: Wed, 19 Oct 2022 22:42:36 +0000	[thread overview]
Message-ID: <Y1B9XFeGw5Q/k3Ax@google.com> (raw)
In-Reply-To: <20220929225203.2234702-2-jmattson@google.com>

On Thu, Sep 29, 2022, Jim Mattson wrote:
> KVM_GET_SUPPORTED_CPUID should only enumerate features that KVM
> actually supports. CPUID.80000006H:EDX[17:16] are reserved bits and
> should be masked off.
> 
> Fixes: 43d05de2bee7 ("KVM: pass through CPUID(0x80000006)")
> Signed-off-by: Jim Mattson <jmattson@google.com>
> ---
>  arch/x86/kvm/cpuid.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
> index ea4e213bcbfb..90f9c295825d 100644
> --- a/arch/x86/kvm/cpuid.c
> +++ b/arch/x86/kvm/cpuid.c
> @@ -1125,6 +1125,7 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
>  		break;
>  	case 0x80000006:
>  		/* L2 cache and TLB: pass through host info. */

Might be worth tweaking the comment, e.g. to

		/* L2 cache and TLB: advertise host info, sans reserved bits. */

> +		entry->edx &= ~GENMASK(17, 16);
>  		break;
>  	case 0x80000007: /* Advanced power management */
>  		/* invariant TSC is CPUID.80000007H:EDX[8] */
> -- 
> 2.38.0.rc1.362.ged0d419d3c-goog
> 

  parent reply	other threads:[~2022-10-19 22:42 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-29 22:51 [PATCH 1/6] KVM: x86: Mask off reserved bits in CPUID.80000001H Jim Mattson
2022-09-29 22:51 ` [PATCH 2/6] KVM: x86: Mask off reserved bits in CPUID.80000006H Jim Mattson
2022-09-30 21:20   ` Dong, Eddie
2022-09-30 23:12     ` Jim Mattson
2022-09-30 23:59       ` Dong, Eddie
2022-10-01  0:35         ` Jim Mattson
2022-10-03 19:35           ` Dong, Eddie
2022-10-03 20:18             ` Jim Mattson
2022-10-05  0:08               ` Dong, Eddie
2022-10-05  2:59                 ` Jim Mattson
2022-10-05 17:09                   ` Dong, Eddie
2022-10-19 22:42   ` Sean Christopherson [this message]
2022-09-29 22:52 ` [PATCH 3/6] KVM: x86: Mask off reserved bits in CPUID.80000008H Jim Mattson
2022-10-19 22:49   ` Sean Christopherson
2022-09-29 22:52 ` [PATCH 4/6] KVM: x86: Mask off reserved bits in CPUID.8000001AH Jim Mattson
2022-09-29 22:52 ` [PATCH 5/6] KVM: x86: Mask off reserved bits in CPUID.8000001EH Jim Mattson
2022-10-19 22:53   ` Sean Christopherson
2022-10-22  8:26     ` Paolo Bonzini
2022-09-29 22:52 ` [PATCH 6/6] KVM: x86: Mask off reserved bits in CPUID.8000001FH Jim Mattson
2022-10-22  8:34   ` Paolo Bonzini
2022-09-30 21:04 ` [PATCH 1/6] KVM: x86: Mask off reserved bits in CPUID.80000001H Dong, Eddie
2022-09-30 23:14   ` Jim Mattson
2022-10-19 22:58 ` Sean Christopherson
2022-10-22  8:36   ` Paolo Bonzini

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