linux-kernel - [PATCH v6 09/16] x86/cpufeatures: Add synthetic Secure TSC bit

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Message-ID: <20231128125959.1810039-10-nikunj@amd.com>
Date:   Tue, 28 Nov 2023 18:29:52 +0530
From:   Nikunj A Dadhania <nikunj@....com>
To:     <linux-kernel@...r.kernel.org>, <thomas.lendacky@....com>,
        <x86@...nel.org>, <kvm@...r.kernel.org>
CC:     <bp@...en8.de>, <mingo@...hat.com>, <tglx@...utronix.de>,
        <dave.hansen@...ux.intel.com>, <dionnaglaze@...gle.com>,
        <pgonda@...gle.com>, <seanjc@...gle.com>, <pbonzini@...hat.com>,
        <nikunj@....com>
Subject: [PATCH v6 09/16] x86/cpufeatures: Add synthetic Secure TSC bit

Add support for the synthetic CPUID flag which indicates that the SNP
guest is running with secure tsc enabled (MSR_AMD64_SEV Bit 11 -
SecureTsc_Enabled) . This flag is there so that this capability in the
guests can be detected easily without reading MSRs every time accessors.

Suggested-by: Kirill A. Shutemov <kirill.shutemov@...ux.intel.com>
Signed-off-by: Nikunj A Dadhania <nikunj@....com>
---
 arch/x86/include/asm/cpufeatures.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 4af140cf5719..e9dafc8cd9dc 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -237,6 +237,7 @@
 #define X86_FEATURE_PVUNLOCK		( 8*32+20) /* "" PV unlock function */
 #define X86_FEATURE_VCPUPREEMPT		( 8*32+21) /* "" PV vcpu_is_preempted function */
 #define X86_FEATURE_TDX_GUEST		( 8*32+22) /* Intel Trust Domain Extensions Guest */
+#define X86_FEATURE_SNP_SECURE_TSC	( 8*32+23) /* "" AMD SNP Secure TSC */
 
 /* Intel-defined CPU features, CPUID level 0x00000007:0 (EBX), word 9 */
 #define X86_FEATURE_FSGSBASE		( 9*32+ 0) /* RDFSBASE, WRFSBASE, RDGSBASE, WRGSBASE instructions*/
-- 
2.34.1