linux-kernel - [PATCH 22/23] x86/cpufeatures: Add the Virtual SPEC

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Date:   Tue,  2 Mar 2021 14:33:42 -0500
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     seanjc@...gle.com, Babu Moger <babu.moger@....com>,
        Borislav Petkov <bp@...e.de>
Subject: [PATCH 22/23] x86/cpufeatures: Add the Virtual SPEC_CTRL feature

From: Babu Moger <babu.moger@....com>

Newer AMD processors have a feature to virtualize the use of the
SPEC_CTRL MSR. Presence of this feature is indicated via CPUID
function 0x8000000A_EDX[20]: GuestSpecCtrl. When present, the
SPEC_CTRL MSR is automatically virtualized.

Signed-off-by: Babu Moger <babu.moger@....com>
Acked-by: Borislav Petkov <bp@...e.de>
Message-Id: <161188100272.28787.4097272856384825024.stgit@...ger-ubuntu>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.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 f1957b3c8e4e..9ac7ad4d8239 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -338,6 +338,7 @@
 #define X86_FEATURE_AVIC		(15*32+13) /* Virtual Interrupt Controller */
 #define X86_FEATURE_V_VMSAVE_VMLOAD	(15*32+15) /* Virtual VMSAVE VMLOAD */
 #define X86_FEATURE_VGIF		(15*32+16) /* Virtual GIF */
+#define X86_FEATURE_V_SPEC_CTRL		(15*32+20) /* Virtual SPEC_CTRL */
 #define X86_FEATURE_SVME_ADDR_CHK	(15*32+28) /* "" SVME addr check */
 
 /* Intel-defined CPU features, CPUID level 0x00000007:0 (ECX), word 16 */
-- 
2.26.2