linux-kernel - [PATCH 1/1] KVM: pass through CPUID(0x80000006)

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Message-Id: <20200415012320.236065-1-jcargill@google.com>
Date:   Tue, 14 Apr 2020 18:23:20 -0700
From:   Jon Cargille <jcargill@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
        kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Eric Northup <digitaleric@...il.com>,
        Eric Northup <digitaleric@...gle.com>,
        Jon Cargille <jcargill@...gle.com>
Subject: [PATCH 1/1] KVM: pass through CPUID(0x80000006)

From: Eric Northup <digitaleric@...il.com>

Return L2 cache and TLB information to guests.
They could have been set before, but the defaults that KVM returns will be
necessary for usermode that doesn't supply their own CPUID tables.

Signed-off-by: Eric Northup <digitaleric@...gle.com>
Signed-off-by: Eric Northup <digitaleric@...il.com>
Signed-off-by: Jon Cargille <jcargill@...gle.com>
Signed-off-by: Jim Mattson <jmattson@...gle.com>
---
 arch/x86/kvm/cpuid.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index b1c469446b072..4a8d67303a42c 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -734,6 +734,9 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
 		entry->ecx &= kvm_cpuid_8000_0001_ecx_x86_features;
 		cpuid_mask(&entry->ecx, CPUID_8000_0001_ECX);
 		break;
+	case 0x80000006:
+		/* L2 cache and TLB: pass through host info. */
+		break;
 	case 0x80000007: /* Advanced power management */
 		/* invariant TSC is CPUID.80000007H:EDX[8] */
 		entry->edx &= (1 << 8);
-- 
2.25.1.481.gfbce0eb801-goog