linux-kernel - [PATCH 3.16 293/305] KVM: x86: Add MSR_AMD64_DC

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Message-ID: <lsq.1549201508.327775223@decadent.org.uk>
Date:   Sun, 03 Feb 2019 14:45:08 +0100
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, Denis Kirjanov <kda@...ux-powerpc.org>,
        "Radim Krčmář" <rkrcmar@...hat.com>,
        "Ladi Prosek" <lprosek@...hat.com>
Subject: [PATCH 3.16 293/305] KVM: x86: Add MSR_AMD64_DC_CFG to the list
 of ignored MSRs

3.16.63-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Ladi Prosek <lprosek@...hat.com>

commit 405a353a0e20d09090ad96147da6afad9b0ce056 upstream.

Hyper-V writes 0x800000000000 to MSR_AMD64_DC_CFG when running on AMD CPUs
as recommended in erratum 383, analogous to our svm_init_erratum_383.

By ignoring the MSR, this patch enables running Hyper-V in L1 on AMD.

Signed-off-by: Ladi Prosek <lprosek@...hat.com>
Signed-off-by: Radim Krčmář <rkrcmar@...hat.com>
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 arch/x86/kvm/x86.c | 2 ++
 1 file changed, 2 insertions(+)

--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2085,6 +2085,7 @@ int kvm_set_msr_common(struct kvm_vcpu *
 	case MSR_VM_HSAVE_PA:
 	case MSR_AMD64_PATCH_LOADER:
 	case MSR_AMD64_BU_CFG2:
+	case MSR_AMD64_DC_CFG:
 		break;
 
 	case MSR_EFER:
@@ -2462,6 +2463,7 @@ int kvm_get_msr_common(struct kvm_vcpu *
 	case MSR_FAM10H_MMIO_CONF_BASE:
 	case MSR_AMD64_BU_CFG2:
 	case MSR_IA32_PERF_CTL:
+	case MSR_AMD64_DC_CFG:
 		msr_info->data = 0;
 		break;
 	case MSR_P6_PERFCTR0: