KVM: VMX: Skip VMCLEAR logic during emergency reboots if CR4.VMXE=0

Bail from vmx_emergency_disable() without processing the list of loaded
VMCSes if CR4.VMXE=0, i.e. if the CPU can't be post-VMXON.  It should be
impossible for the list to have entries if VMX is already disabled, and
even if that invariant doesn't hold, VMCLEAR will #UD anyways, i.e.
processing the list is pointless even if it somehow isn't empty.

Assuming no existing KVM bugs, this should be a glorified nop.  The
primary motivation for the change is to avoid having code that looks like
it does VMCLEAR, but then skips VMXON, which is nonsensical.

Suggested-by: Kai Huang <[email protected]>
Reviewed-by: Kai Huang <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Sean Christopherson <[email protected]>

0 files changed, 0 insertions, 0 deletions