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KVM: X86: #GP when guest attempts to write MCi_STATUS register w/o 0 

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>
hifive-unleashed-5.1
Wanpeng Li 2017-10-19 06:47:56 -07:00 committed by Radim Krčmář
parent 61f1dd9099
commit 9ffd986c6e
1 changed files with 7 additions and 2 deletions
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9
arch/x86/kvm/x86.c
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@ -2006,10 +2006,12 @@ static void kvmclock_sync_fn(struct work_struct *work)
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 @@ static int set_msr_mce(struct kvm_vcpu *vcpu, u32 msr, u64 data)
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 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
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: