[PATCH 6/6] KVM: perform a wake_up in kvm_make_all_cpus_request

From: Radim KrÄmÃÅ
Date: Thu Apr 06 2017 - 16:22:04 EST


We want to have kvm_make_all_cpus_request() to be an optmized version of

kvm_for_each_vcpu(i, vcpu, kvm) {
kvm_make_request(vcpu, request);
kvm_vcpu_kick(vcpu);
}

and kvm_vcpu_kick() wakes up the target vcpu. We know which requests do
not need the wake up and use it to optimize the loop.

Thanks to that, this patch doesn't change the behavior of current users
(the all don't need the wake up) and only prepares for future where the
wake up is going to be needed.

I think that most requests do not need the wake up, so we would flip the
bit then.

Signed-off-by: Radim KrÄmÃÅ <rkrcmar@xxxxxxxxxx>
---
virt/kvm/kvm_main.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index a486c6ad27a6..1db503bab3dc 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -186,6 +186,9 @@ bool kvm_make_all_cpus_request(struct kvm *kvm, unsigned int req)
/* Set ->requests bit before we read ->mode. */
smp_mb__after_atomic();

+ if (!(req & KVM_REQUEST_NO_WAKEUP))
+ kvm_vcpu_wake_up(vcpu);
+
if (cpus != NULL && cpu != -1 && cpu != me &&
kvm_arch_vcpu_should_kick(vcpu))
cpumask_set_cpu(cpu, cpus);
--
2.12.0