[PATCH 3.13.y-ckt 26/48] KVM: x86: trap AMD MSRs for the TSeg base and mask

From: Kamal Mostafa
Date: Tue Oct 27 2015 - 17:42:00 EST


3.13.11-ckt29 -stable 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>
[ luis: backported to 3.16:
- file rename: arch/x86/include/asm/msr-index.h ->
arch/x86/include/uapi/asm/msr-index.h
- adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>

Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
arch/x86/include/uapi/asm/msr-index.h | 1 +
arch/x86/kvm/x86.c | 2 ++
2 files changed, 3 insertions(+)

diff --git a/arch/x86/include/uapi/asm/msr-index.h b/arch/x86/include/uapi/asm/msr-index.h
index 59cea18..87c2dcf 100644
--- a/arch/x86/include/uapi/asm/msr-index.h
+++ b/arch/x86/include/uapi/asm/msr-index.h
@@ -232,6 +232,7 @@
/* 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 */
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index d1a0937..8f83ea4 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2377,6 +2377,8 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata)
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_K7_EVNTSEL0:
--
1.9.1

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