KVM: VMX: Disable preemption when probing user return MSRs

Disable preemption when probing a user return MSR via RDSMR/WRMSR.  If
the MSR holds a different value per logical CPU, the WRMSR could corrupt
the host's value if KVM is preempted between the RDMSR and WRMSR, and
then rescheduled on a different CPU.

Opportunistically land the helper in common x86, SVM will use the helper
in a future commit.

Fixes: 4be534102624 ("KVM: VMX: Initialize vmx->guest_msrs[] right after allocation")
Cc: [email protected]
Cc: Xiaoyao Li <[email protected]>
Signed-off-by: Sean Christopherson <[email protected]>
Message-Id: <[email protected]>
Reviewed-by: Jim Mattson <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>

0 files changed, 0 insertions, 0 deletions