Simplify the handling of lazy EE by going directly from fully-enabled to hard-disabled. This replaces the lazy_irq_pending() check (including its misplaced kvm_guest_exit() call). As suggested by Tiejun Chen, move the interrupt disabling into kvmppc_prepare_to_enter() rather than have each caller do it. Also move the IRQ enabling on heavyweight exit into kvmppc_prepare_to_enter(). Don't move kvmppc_fix_ee_before_entry() into kvmppc_prepare_to_enter(), so that the caller can avoid marking interrupts enabled earlier than necessary (e.g. book3s_pr waits until after FP save/restore is done). Signed-off-by: Scott Wood <scottwood@xxxxxxxxxxxxx> --- arch/powerpc/include/asm/kvm_ppc.h | 6 ++++++ arch/powerpc/kvm/book3s_pr.c | 12 +++--------- arch/powerpc/kvm/booke.c | 9 ++------- arch/powerpc/kvm/powerpc.c | 21 ++++++++------------- 4 files changed, 19 insertions(+), 29 deletions(-) diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h index 6885846..e4474f8 100644 --- a/arch/powerpc/include/asm/kvm_ppc.h +++ b/arch/powerpc/include/asm/kvm_ppc.h @@ -404,6 +404,12 @@ static inline void kvmppc_fix_ee_before_entry(void) trace_hardirqs_on(); #ifdef CONFIG_PPC64 + /* + * To avoid races, the caller must have gone directly from having + * interrupts fully-enabled to hard-disabled. + */ + WARN_ON(local_paca->irq_happened != PACA_IRQ_HARD_DIS); + /* Only need to enable IRQs by hard enabling them after this */ local_paca->irq_happened = 0; local_paca->soft_enabled = 1; diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c index 0b97ce4..e61e39e 100644 --- a/arch/powerpc/kvm/book3s_pr.c +++ b/arch/powerpc/kvm/book3s_pr.c @@ -884,14 +884,11 @@ program_interrupt: * and if we really did time things so badly, then we just exit * again due to a host external interrupt. */ - local_irq_disable(); s = kvmppc_prepare_to_enter(vcpu); - if (s <= 0) { - local_irq_enable(); + if (s <= 0) r = s; - } else { + else kvmppc_fix_ee_before_entry(); - } } trace_kvm_book3s_reenter(r, vcpu); @@ -1121,12 +1118,9 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu) * really did time things so badly, then we just exit again due to * a host external interrupt. */ - local_irq_disable(); ret = kvmppc_prepare_to_enter(vcpu); - if (ret <= 0) { - local_irq_enable(); + if (ret <= 0) goto out; - } /* Save FPU state in stack */ if (current->thread.regs->msr & MSR_FP) diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c index eb89b83..f7c0111 100644 --- a/arch/powerpc/kvm/booke.c +++ b/arch/powerpc/kvm/booke.c @@ -666,10 +666,8 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu) return -EINVAL; } - local_irq_disable(); s = kvmppc_prepare_to_enter(vcpu); if (s <= 0) { - local_irq_enable(); ret = s; goto out; } @@ -1148,14 +1146,11 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu, * aren't already exiting to userspace for some other reason. */ if (!(r & RESUME_HOST)) { - local_irq_disable(); s = kvmppc_prepare_to_enter(vcpu); - if (s <= 0) { - local_irq_enable(); + if (s <= 0) r = (s << 2) | RESUME_HOST | (r & RESUME_FLAG_NV); - } else { + else kvmppc_fix_ee_before_entry(); - } } return r; diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c index 4e05f8c..f8659aa 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -64,12 +64,14 @@ int kvmppc_prepare_to_enter(struct kvm_vcpu *vcpu) { int r = 1; - WARN_ON_ONCE(!irqs_disabled()); + WARN_ON(irqs_disabled()); + hard_irq_disable(); + while (true) { if (need_resched()) { local_irq_enable(); cond_resched(); - local_irq_disable(); + hard_irq_disable(); continue; } @@ -95,7 +97,7 @@ int kvmppc_prepare_to_enter(struct kvm_vcpu *vcpu) local_irq_enable(); trace_kvm_check_requests(vcpu); r = kvmppc_core_check_requests(vcpu); - local_irq_disable(); + hard_irq_disable(); if (r > 0) continue; break; @@ -108,21 +110,14 @@ int kvmppc_prepare_to_enter(struct kvm_vcpu *vcpu) } #ifdef CONFIG_PPC64 - /* lazy EE magic */ - hard_irq_disable(); - if (lazy_irq_pending()) { - /* Got an interrupt in between, try again */ - local_irq_enable(); - local_irq_disable(); - kvm_guest_exit(); - continue; - } + WARN_ON(lazy_irq_pending()); #endif kvm_guest_enter(); - break; + return r; } + local_irq_enable(); return r; } #endif /* CONFIG_KVM_BOOK3S_64_HV */ -- 1.7.10.4 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html