> -----Original Message----- > From: kvm-ppc-owner@xxxxxxxxxxxxxxx [mailto:kvm-ppc-owner@xxxxxxxxxxxxxxx] On > Behalf Of Scott Wood > Sent: Friday, May 10, 2013 8:40 AM > To: Alexander Graf; Benjamin Herrenschmidt > Cc: kvm-ppc@xxxxxxxxxxxxxxx; kvm@xxxxxxxxxxxxxxx; linuxppc-dev@xxxxxxxxxxxxxxxx; > Wood Scott-B07421 > Subject: [PATCH v2 4/4] kvm/ppc: IRQ disabling cleanup > > 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(); Ok, Now we do not soft disable before kvmppc_prapare_to_enter(). > 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(); Here we hard disable in kvmppc_prepare_to_enter(), so my comment in other patch about interrupt loss is no more valid. So here MSR.EE = 0 local_paca->soft_enabled = 0 local_paca->irq_happened |= PACA_IRQ_HARD_DIS; > + > while (true) { > if (need_resched()) { > local_irq_enable(); This will make the state: MSR.EE = 1 local_paca->soft_enabled = 1 local_paca->irq_happened = PACA_IRQ_HARD_DIS; //same as before Is that a valid state where interrupts are fully enabled and irq_happend in not 0? > 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; > } int kvmppc_core_prepare_to_enter(struct kvm_vcpu *vcpu) { int r = 0; WARN_ON_ONCE(!irqs_disabled()); kvmppc_core_check_exceptions(vcpu); if (vcpu->requests) { /* Exception delivery raised request; start over */ return 1; } if (vcpu->arch.shared->msr & MSR_WE) { local_irq_enable(); kvm_vcpu_block(vcpu); clear_bit(KVM_REQ_UNHALT, &vcpu->requests); local_irq_disable(); ^^^ We do not require hard_irq_disable() here? -Bharat > #endif /* CONFIG_KVM_BOOK3S_64_HV */ > -- > 1.7.10.4 > > > -- > To unsubscribe from this list: send the line "unsubscribe kvm-ppc" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- 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
