From: Wanpeng Li <wanpeng.li@hotmail.com>
Date: Thu, 19 Oct 2017 06:47:56 -0700
Subject: KVM: X86: #GP when guest attempts to write MCi_STATUS register w/o 0
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Patch-mainline: v4.15-rc1
Git-commit: 9ffd986c6e4e59c11857cbc78e4217e9569f3725
References: bsc#1077761
Both Intel SDM and AMD APM mentioned that MCi_STATUS, when the register is
implemented, this register can be cleared by explicitly writing 0s to this
register. Writing 1s to this register will cause a general-protection
exception.
The mce is emulated in qemu, so just the guest attempts to write 1 to this
register should cause a #GP, this patch does it.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Jim Mattson <jmattson@google.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Acked-by: Alexander Graf <agraf@suse.de>
---
arch/x86/kvm/x86.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2006,10 +2006,12 @@
KVMCLOCK_SYNC_PERIOD);
}
-static int set_msr_mce(struct kvm_vcpu *vcpu, u32 msr, u64 data)
+static int set_msr_mce(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
{
u64 mcg_cap = vcpu->arch.mcg_cap;
unsigned bank_num = mcg_cap & 0xff;
+ u32 msr = msr_info->index;
+ u64 data = msr_info->data;
switch (msr) {
case MSR_IA32_MCG_STATUS:
@@ -2034,6 +2036,9 @@
if ((offset & 0x3) == 0 &&
data != 0 && (data | (1 << 10)) != ~(u64)0)
return -1;
+ if (!msr_info->host_initiated &&
+ (offset & 0x3) == 1 && data != 0)
+ return -1;
vcpu->arch.mce_banks[offset] = data;
break;
}
@@ -2283,7 +2288,7 @@
case MSR_IA32_MCG_CTL:
case MSR_IA32_MCG_STATUS:
case MSR_IA32_MC0_CTL ... MSR_IA32_MCx_CTL(KVM_MAX_MCE_BANKS) - 1:
- return set_msr_mce(vcpu, msr, data);
+ return set_msr_mce(vcpu, msr_info);
case MSR_K7_PERFCTR0 ... MSR_K7_PERFCTR3:
case MSR_P6_PERFCTR0 ... MSR_P6_PERFCTR1: