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authorMarcelo Tosatti <mtosatti@redhat.com>2009-05-07 17:55:12 -0300
committerAvi Kivity <avi@redhat.com>2009-06-10 11:48:53 +0300
commit32f8840064d88cc3f6e85203aec7b6b57bebcb97 (patch)
tree29a42942c71e9bdf1f3e71aa1674a29aa13ce320 /arch/ia64
parentd149c731e4f71982247a14409951259f36271dd7 (diff)
KVM: use smp_send_reschedule in kvm_vcpu_kick
KVM uses a function call IPI to cause the exit of a guest running on a physical cpu. For virtual interrupt notification there is no need to wait on IPI receival, or to execute any function. This is exactly what the reschedule IPI does, without the overhead of function IPI. So use it instead of smp_call_function_single in kvm_vcpu_kick. Also change the "guest_mode" variable to a bit in vcpu->requests, and use that to collapse multiple IPI's that would be issued between the first one and zeroing of guest mode. This allows kvm_vcpu_kick to called with interrupts disabled. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'arch/ia64')
-rw-r--r--arch/ia64/kernel/irq_ia64.c3
-rw-r--r--arch/ia64/kvm/kvm-ia64.c22
2 files changed, 11 insertions, 14 deletions
diff --git a/arch/ia64/kernel/irq_ia64.c b/arch/ia64/kernel/irq_ia64.c
index acc4d19ae62a..b448197728be 100644
--- a/arch/ia64/kernel/irq_ia64.c
+++ b/arch/ia64/kernel/irq_ia64.c
@@ -610,6 +610,9 @@ static struct irqaction ipi_irqaction = {
.name = "IPI"
};
+/*
+ * KVM uses this interrupt to force a cpu out of guest mode
+ */
static struct irqaction resched_irqaction = {
.handler = dummy_handler,
.flags = IRQF_DISABLED,
diff --git a/arch/ia64/kvm/kvm-ia64.c b/arch/ia64/kvm/kvm-ia64.c
index be4413e1f43f..80c57b0a21c4 100644
--- a/arch/ia64/kvm/kvm-ia64.c
+++ b/arch/ia64/kvm/kvm-ia64.c
@@ -668,7 +668,7 @@ again:
host_ctx = kvm_get_host_context(vcpu);
guest_ctx = kvm_get_guest_context(vcpu);
- vcpu->guest_mode = 1;
+ clear_bit(KVM_REQ_KICK, &vcpu->requests);
r = kvm_vcpu_pre_transition(vcpu);
if (r < 0)
@@ -685,7 +685,7 @@ again:
kvm_vcpu_post_transition(vcpu);
vcpu->arch.launched = 1;
- vcpu->guest_mode = 0;
+ set_bit(KVM_REQ_KICK, &vcpu->requests);
local_irq_enable();
/*
@@ -1879,24 +1879,18 @@ void kvm_arch_hardware_unsetup(void)
{
}
-static void vcpu_kick_intr(void *info)
-{
-#ifdef DEBUG
- struct kvm_vcpu *vcpu = (struct kvm_vcpu *)info;
- printk(KERN_DEBUG"vcpu_kick_intr %p \n", vcpu);
-#endif
-}
-
void kvm_vcpu_kick(struct kvm_vcpu *vcpu)
{
- int ipi_pcpu = vcpu->cpu;
- int cpu = get_cpu();
+ int me;
+ int cpu = vcpu->cpu;
if (waitqueue_active(&vcpu->wq))
wake_up_interruptible(&vcpu->wq);
- if (vcpu->guest_mode && cpu != ipi_pcpu)
- smp_call_function_single(ipi_pcpu, vcpu_kick_intr, vcpu, 0);
+ me = get_cpu();
+ if (cpu != me && (unsigned) cpu < nr_cpu_ids && cpu_online(cpu))
+ if (!test_and_set_bit(KVM_REQ_KICK, &vcpu->requests))
+ smp_send_reschedule(cpu);
put_cpu();
}