KVM: x86: use guest_exit_irqoff

This gains a few clock cycles per vmexit.  On Intel there is no need
anymore to enable the interrupts in vmx_handle_external_intr, since
we are using the "acknowledge interrupt on exit" feature.  AMD
needs to do that, and must be careful to avoid the interrupt shadow.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 1b413a52..c1d655c 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -8574,7 +8574,6 @@
 			"push %[sp]\n\t"
 #endif
 			"pushf\n\t"
-			"orl $0x200, (%%" _ASM_SP ")\n\t"
 			__ASM_SIZE(push) " $%c[cs]\n\t"
 			"call *%[entry]\n\t"
 			:
@@ -8587,8 +8586,7 @@
 			[ss]"i"(__KERNEL_DS),
 			[cs]"i"(__KERNEL_CS)
 			);
-	} else
-		local_irq_enable();
+	}
 }
 
 static bool vmx_has_high_real_mode_segbase(void)