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From: Thomas Voegtle <tv@lio96.de>
To: Ben Hutchings <ben@decadent.org.uk>
Cc: "Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com>,
	x86@kernel.org, kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Ingo Molnar" <mingo@redhat.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	stable@vger.kernel.org
Subject: Re: [PATCH] KVM: VMX: Expose SSBD properly to guests.
Date: Thu, 7 Jun 2018 15:14:14 +0200 (CEST)	[thread overview]
Message-ID: <alpine.LNX.2.21.1806071510590.7445@collaps.dev.collax.com> (raw)
In-Reply-To: <b92df74ecb0399db0fc1be49361134870d016421.camel@decadent.org.uk>

[-- Attachment #1: Type: text/plain, Size: 2086 bytes --]

On Wed, 23 May 2018, Ben Hutchings wrote:

> On Mon, 2018-05-21 at 17:54 -0400, Konrad Rzeszutek Wilk wrote:
>> The X86_FEATURE_SSBD is an synthetic CPU feature - that is
>> it bit location has no relevance to the real CPUID 0x7.EBX[31]
>> bit position. For that we need the new CPU feature name.
>>
>> Fixes: 52817587e706 ("x86/cpufeatures: Disentangle SSBD enumeration")
>>
>> CC: Paolo Bonzini <pbonzini@redhat.com>
>> Cc: "Radim Krčmář" <rkrcmar@redhat.com>
>> Cc: Thomas Gleixner <tglx@linutronix.de>
>> Cc: Ingo Molnar <mingo@redhat.com>
>> Cc: "H. Peter Anvin" <hpa@zytor.com>
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
>> ---
>>  arch/x86/kvm/cpuid.c | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
>> index ced851169730..598461e24be3 100644
>> --- a/arch/x86/kvm/cpuid.c
>> +++ b/arch/x86/kvm/cpuid.c
>> @@ -407,8 +407,8 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
>>
>>  	/* cpuid 7.0.edx*/
>>  	const u32 kvm_cpuid_7_0_edx_x86_features =
>> -		F(AVX512_4VNNIW) | F(AVX512_4FMAPS) | F(SPEC_CTRL) | F(SSBD) |
>> -		F(ARCH_CAPABILITIES);
>> +		F(AVX512_4VNNIW) | F(AVX512_4FMAPS) | F(SPEC_CTRL) |
>> +		F(SPEC_CTRL_SSBD) | F(ARCH_CAPABILITIES);
>>
>>  	/* all calls to cpuid_count() should be made on the same cpu */
>>  	get_cpu();
>
> For 4.9-stable, guest_cpuid_has_spec_ctrl() needs a similar fix.
>
> Ben.

Do you mean something like this?

--- a/arch/x86/kvm/cpuid.h
+++ b/arch/x86/kvm/cpuid.h
@@ -179,7 +179,7 @@ static inline bool guest_cpuid_has_spec_ctrl(struct 
kvm_vcpu *vcpu)
         if (best && (best->ebx & bit(X86_FEATURE_AMD_IBRS)))
                 return true;
         best = kvm_find_cpuid_entry(vcpu, 7, 0);
-       return best && (best->edx & (bit(X86_FEATURE_SPEC_CTRL) | 
bit(X86_FEATURE_SSBD)));
+       return best && (best->edx & (bit(X86_FEATURE_SPEC_CTRL) | 
bit(X86_FEATURE_SPEC_CTRL_SSBD)));
  }

  static inline bool guest_cpuid_has_arch_capabilities(struct kvm_vcpu 
*vcpu)

  reply	other threads:[~2018-06-07 13:25 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-21 21:54 [PATCH] Fix SSBD not being exposed to guests. (v1) Konrad Rzeszutek Wilk
2018-05-21 21:54 ` [PATCH] KVM: VMX: Expose SSBD properly to guests Konrad Rzeszutek Wilk
2018-05-22 23:50   ` Ben Hutchings
2018-06-07 13:14     ` Thomas Voegtle [this message]
2018-05-23  9:00   ` [tip:x86/pti] KVM/VMX: " tip-bot for Konrad Rzeszutek Wilk

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