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/svm.c b/arch/x86/kvm/svm.c
index 5ff2927..5bfdbbf 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -4935,6 +4935,12 @@
static void svm_handle_external_intr(struct kvm_vcpu *vcpu)
{
local_irq_enable();
+ /*
+ * We must have an instruction with interrupts enabled, so
+ * the timer interrupt isn't delayed by the interrupt shadow.
+ */
+ asm("nop");
+ local_irq_disable();
}
static void svm_sched_in(struct kvm_vcpu *vcpu, int cpu)
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)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 618463a..0cc6cf8 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6709,16 +6709,9 @@
++vcpu->stat.exits;
- /*
- * We must have an instruction between local_irq_enable() and
- * kvm_guest_exit(), so the timer interrupt isn't delayed by
- * the interrupt shadow. The stat.exits increment will do nicely.
- * But we need to prevent reordering, hence this barrier():
- */
- barrier();
+ guest_exit_irqoff();
- guest_exit();
-
+ local_irq_enable();
preempt_enable();
vcpu->srcu_idx = srcu_read_lock(&vcpu->kvm->srcu);
