linux-kernel - [PATCH 5.10 50/52] KVM: x86: Hide IA32_PLATFORM_DCA

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Date:   Mon,  3 Oct 2022 09:11:57 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Jim Mattson <jmattson@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.10 50/52] KVM: x86: Hide IA32_PLATFORM_DCA_CAP[31:0] from the guest

From: Jim Mattson <jmattson@...gle.com>

[ Upstream commit aae2e72229cdb21f90df2dbe4244c977e5d3265b ]

The only thing reported by CPUID.9 is the value of
IA32_PLATFORM_DCA_CAP[31:0] in EAX. This MSR doesn't even exist in the
guest, since CPUID.1:ECX.DCA[bit 18] is clear in the guest.

Clear CPUID.9 in KVM_GET_SUPPORTED_CPUID.

Fixes: 24c82e576b78 ("KVM: Sanitize cpuid")
Signed-off-by: Jim Mattson <jmattson@...gle.com>
Message-Id: <20220922231854.249383-1-jmattson@...gle.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/x86/kvm/cpuid.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index 6e1ea5e85e59..6f44274aa949 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -661,8 +661,6 @@ static inline int __do_cpuid_func(struct kvm_cpuid_array *array, u32 function)
 			entry->edx = 0;
 		}
 		break;
-	case 9:
-		break;
 	case 0xa: { /* Architectural Performance Monitoring */
 		struct x86_pmu_capability cap;
 		union cpuid10_eax eax;
-- 
2.35.1