From 6b7e2d0991489559a1df4500d77f7b76c4607ed0 Mon Sep 17 00:00:00 2001 From: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> Date: Wed, 12 Jan 2011 15:40:31 +0800 Subject: KVM: Add "exiting guest mode" state Currently we keep track of only two states: guest mode and host mode. This patch adds an "exiting guest mode" state that tells us that an IPI will happen soon, so unless we need to wait for the IPI, we can avoid it completely. Also 1: No need atomically to read/write ->mode in vcpu's thread 2: reorganize struct kvm_vcpu to make ->mode and ->requests in the same cache line explicitly Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> Signed-off-by: Avi Kivity <avi@redhat.com> --- virt/kvm/kvm_main.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'virt') diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index fd67bcde9980..19209f849cf7 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -171,7 +171,12 @@ static bool make_all_cpus_request(struct kvm *kvm, unsigned int req) if (kvm_make_check_request(req, vcpu)) continue; cpu = vcpu->cpu; - if (cpus != NULL && cpu != -1 && cpu != me) + + /* Set ->requests bit before we read ->mode */ + smp_mb(); + + if (cpus != NULL && cpu != -1 && cpu != me && + kvm_vcpu_exiting_guest_mode(vcpu) != OUTSIDE_GUEST_MODE) cpumask_set_cpu(cpu, cpus); } if (unlikely(cpus == NULL)) -- cgit v1.2.2