lk/linux-kernel-test
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

KVM: use smp_send_reschedule in kvm_vcpu_kick

Browse Source 
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>
This commit is contained in:
Marcelo Tosatti
2009-05-07 17:55:12 -03:00
committed by Avi Kivity
parent d149c731e4
commit 32f8840064
5 changed files with 26 additions and 40 deletions
Download Patch File Download Diff File Expand all files Collapse all files

22
arch/ia64/kvm/kvm-ia64.c
View File

@ -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();
}