[PATCH 3.2 080/107] KVM: x86: trap AMD MSRs for the TSeg base and mask

From: Ben Hutchings
Date: Thu Oct 08 2015 - 20:21:39 EST


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

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

From: Paolo Bonzini <pbonzini@xxxxxxxxxx>

commit 3afb1121800128aae9f5722e50097fcf1a9d4d88 upstream.

These have roughly the same purpose as the SMRR, which we do not need
to implement in KVM. However, Linux accesses MSR_K8_TSEG_ADDR at
boot, which causes problems when running a Xen dom0 under KVM.
Just return 0, meaning that processor protection of SMRAM is not
in effect.

Reported-by: M A Young <m.a.young@xxxxxxxxxxxx>
Acked-by: Borislav Petkov <bp@xxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
arch/x86/include/asm/msr-index.h | 1 +
arch/x86/kvm/x86.c | 2 ++
2 files changed, 3 insertions(+)

--- a/arch/x86/include/asm/msr-index.h
+++ b/arch/x86/include/asm/msr-index.h
@@ -159,6 +159,7 @@
/* C1E active bits in int pending message */
#define K8_INTP_C1E_ACTIVE_MASK 0x18000000
#define MSR_K8_TSEG_ADDR 0xc0010112
+#define MSR_K8_TSEG_MASK 0xc0010113
#define K8_MTRRFIXRANGE_DRAM_ENABLE 0x00040000 /* MtrrFixDramEn bit */
#define K8_MTRRFIXRANGE_DRAM_MODIFY 0x00080000 /* MtrrFixDramModEn bit */
#define K8_MTRR_RDMEM_WRMEM_MASK 0x18181818 /* Mask: RdMem|WrMem */
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1885,6 +1885,8 @@ int kvm_get_msr_common(struct kvm_vcpu *
case MSR_IA32_LASTINTFROMIP:
case MSR_IA32_LASTINTTOIP:
case MSR_K8_SYSCFG:
+ case MSR_K8_TSEG_ADDR:
+ case MSR_K8_TSEG_MASK:
case MSR_K7_HWCR:
case MSR_VM_HSAVE_PA:
case MSR_P6_PERFCTR0:

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