From: Borislav Petkov <bp@alien8.de>
To: Babu Moger <babu.moger@amd.com>
Cc: pbonzini@redhat.com, tglx@linutronix.de, mingo@redhat.com,
fenghua.yu@intel.com, tony.luck@intel.com, wanpengli@tencent.com,
kvm@vger.kernel.org, thomas.lendacky@amd.com,
peterz@infradead.org, seanjc@google.com, joro@8bytes.org,
x86@kernel.org, kyung.min.park@intel.com,
linux-kernel@vger.kernel.org, krish.sadhukhan@oracle.com,
hpa@zytor.com, mgross@linux.intel.com, vkuznets@redhat.com,
kim.phillips@amd.com, wei.huang2@amd.com, jmattson@google.com
Subject: Re: [PATCH v2 2/2] KVM: SVM: Add support for Virtual SPEC_CTRL
Date: Wed, 30 Dec 2020 08:15:01 +0100 [thread overview]
Message-ID: <20201230071501.GB22022@zn.tnic> (raw)
In-Reply-To: <160867631505.3471.3808049369257008114.stgit@bmoger-ubuntu>
On Tue, Dec 22, 2020 at 04:31:55PM -0600, Babu Moger wrote:
> @@ -2549,7 +2559,10 @@ static int svm_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
> !guest_cpuid_has(vcpu, X86_FEATURE_AMD_SSBD))
> return 1;
>
> - msr_info->data = svm->spec_ctrl;
> + if (static_cpu_has(X86_FEATURE_V_SPEC_CTRL))
> + msr_info->data = svm->vmcb->save.spec_ctrl;
> + else
> + msr_info->data = svm->spec_ctrl;
> break;
> case MSR_AMD64_VIRT_SPEC_CTRL:
> if (!msr_info->host_initiated &&
> @@ -2640,6 +2653,8 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr)
> return 1;
>
> svm->spec_ctrl = data;
> + if (static_cpu_has(X86_FEATURE_V_SPEC_CTRL))
> + svm->vmcb->save.spec_ctrl = data;
> if (!data)
> break;
>
Are the get/set_msr() accessors such a fast path that they need
static_cpu_has() ?
svm_get_msr() already uses boot_cpu_has() for MSR_TSC_AUX...
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2020-12-30 7:15 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-22 22:31 [PATCH v2 0/2] x86: Add the feature Virtual SPEC_CTRL Babu Moger
2020-12-22 22:31 ` [PATCH v2 1/2] x86/cpufeatures: Add the Virtual SPEC_CTRL feature Babu Moger
2020-12-30 7:15 ` Borislav Petkov
2020-12-22 22:31 ` [PATCH v2 2/2] KVM: SVM: Add support for Virtual SPEC_CTRL Babu Moger
2020-12-30 7:15 ` Borislav Petkov [this message]
2020-12-30 16:08 ` Sean Christopherson
2021-01-04 18:37 ` Babu Moger
2021-01-04 15:47 ` Tom Lendacky
2021-01-04 18:35 ` Babu Moger
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