[ Upstream commit 2368048bf5 ]
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: 890ca9aefa ("KVM: Add MCE support")
Fixes: 9ffd986c6e ("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>
e7ccee2f09