Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 5.19 1064/1157] KVM: x86: Signal #GP, not -EPERM, on bad WRMSR(MCi_CTL/STATUS) | Date | Mon, 15 Aug 2022 20:07:00 +0200 |
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From: Sean Christopherson <seanjc@google.com>
[ 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> --- arch/x86/kvm/x86.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3252,13 +3252,13 @@ static int set_msr_mce(struct kvm_vcpu * */ 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;
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