KVM: VMX: check use I/O bitmap first before unconditional I/O exit
KVM: VMX: check use I/O bitmap first before unconditional I/O exit

According to Table C-1 of Intel SDM 3C, a VM exit happens on an I/O instruction when
"use I/O bitmaps" VM-execution control was 0 _and_ the "unconditional I/O exiting"
VM-execution control was 1. So we can't just check "unconditional I/O exiting" alone.
This patch was improved by suggestion from Jan Kiszka.

Reviewed-by: Jan Kiszka <a5b45c9af271d077f30d36aa7d9b988eed9d56eb@siemens.com>
Signed-off-by: Zhihui Zhang <c41e611e46dfba463179e5e3c6f4822a86ffed49@gmail.com>
Signed-off-by: Marcelo Tosatti <958bcd1f4a7a8c36dca09fe3fa9cb5f1483adf51@redhat.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs