Messages in this thread Patch in this message | | | Date | Thu, 12 May 2022 22:27:14 +0000 | Subject | [PATCH 1/3] KVM: x86: Signal #GP, not -EPERM, on bad WRMSR(MCi_CTL/STATUS) | From | Sean Christopherson <> |
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Return '1', not '-1', when handling an illegal WRMSR to a MCi_CTL or MCi_STATUS MSR. The behavior of "all zeros' or "all ones" for CTL MSRs is architectural, as is the "only zeros" behavior for STATUS MSRs. I.e. the intent is to inject a #GP, not exit to userspace due to an unhandled emulation case. Returning '-1' gets interpreted as -EPERM up the stack and effecitvely kills the guest.
Fixes: 890ca9aefa78 ("KVM: Add MCE support") Fixes: 9ffd986c6e4e ("KVM: X86: #GP when guest attempts to write MCi_STATUS register w/o 0") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson <seanjc@google.com> --- arch/x86/kvm/x86.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 8ee8c91fa762..bc6db58975dc 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3233,13 +3233,13 @@ static int set_msr_mce(struct kvm_vcpu *vcpu, struct msr_data *msr_info) */ if ((offset & 0x3) == 0 && data != 0 && (data | (1 << 10)) != ~(u64)0) - return -1; + return 1; /* MCi_STATUS */ if (!msr_info->host_initiated && (offset & 0x3) == 1 && data != 0) { if (!can_set_mci_status(vcpu)) - return -1; + return 1; } vcpu->arch.mce_banks[offset] = data; -- 2.36.0.550.gb090851708-goog
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