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authorSean Christopherson <seanjc@google.com>2022-05-13 01:27:14 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2022-08-21 16:16:17 +0300
commite7ccee2f09b06303fb39f8cb19a2c21d388dc4e6 (patch)
tree45276ecfcaf12989ef9a4d396b55de2b8bfb95d2
parentf5385a590df78d7649876a2087646090e867e6eb (diff)
downloadlinux-e7ccee2f09b06303fb39f8cb19a2c21d388dc4e6.tar.xz
KVM: x86: Signal #GP, not -EPERM, on bad WRMSR(MCi_CTL/STATUS)
[ Upstream commit 2368048bf5c2ec4b604ac3431564071e89a0bc71 ] 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> Reviewed-by: Jim Mattson <jmattson@google.com> Link: https://lore.kernel.org/r/20220512222716.4112548-2-seanjc@google.com Signed-off-by: Sasha Levin <sashal@kernel.org>
-rw-r--r--arch/x86/kvm/x86.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 23a5e5880615..98422a53bb1e 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2869,13 +2869,13 @@ static int set_msr_mce(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
*/
if ((offset & 0x3) == 0 &&
data != 0 && (data | (1 << 10) | 1) != ~(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;