From d5c48debcc4fbdd09e3e0871980b7ebf06ec6e07 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 18 Dec 2019 13:55:17 -0800 Subject: [PATCH] KVM: Move initialization of preempt notifier to kvm_vcpu_init() Initialize the preempt notifier immediately in kvm_vcpu_init() to pave the way for removing kvm_arch_vcpu_setup(), i.e. to allow arch specific code to call vcpu_load() during kvm_arch_vcpu_create(). Back when preemption support was added, the location of the call to init the preempt notifier was perfectly sane. The overall vCPU creation flow featured a single arch specific hook and the preempt notifer was used immediately after its initialization (by vcpu_load()). E.g.: vcpu = kvm_arch_ops->vcpu_create(kvm, n); if (IS_ERR(vcpu)) return PTR_ERR(vcpu); preempt_notifier_init(&vcpu->preempt_notifier, &kvm_preempt_ops); vcpu_load(vcpu); r = kvm_mmu_setup(vcpu); vcpu_put(vcpu); if (r < 0) goto free_vcpu; Today, the call to preempt_notifier_init() is sandwiched between two arch specific calls, kvm_arch_vcpu_create() and kvm_arch_vcpu_setup(), which needlessly forces x86 (and possibly others?) to split its vCPU creation flow. Init the preempt notifier prior to any arch specific call so that each arch can independently decide how best to organize its creation flow. Acked-by: Christoffer Dall Signed-off-by: Sean Christopherson Reviewed-by: Cornelia Huck Signed-off-by: Paolo Bonzini --- virt/kvm/kvm_main.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 44b4e86..1ddb6d4 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -348,6 +348,7 @@ static int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id) kvm_vcpu_set_dy_eligible(vcpu, false); vcpu->preempted = false; vcpu->ready = false; + preempt_notifier_init(&vcpu->preempt_notifier, &kvm_preempt_ops); r = kvm_arch_vcpu_init(vcpu); if (r < 0) @@ -2752,8 +2753,6 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id) if (r) goto vcpu_uninit; - preempt_notifier_init(&vcpu->preempt_notifier, &kvm_preempt_ops); - r = kvm_arch_vcpu_setup(vcpu); if (r) goto vcpu_destroy; -- 2.7.4