From 6c85f52b10fd60e45c6e30c5b85d116406bd3c9b Mon Sep 17 00:00:00 2001 From: Scott Wood Date: Thu, 9 Jan 2014 19:18:40 -0600 Subject: [PATCH] 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(). Signed-off-by: Scott Wood Signed-off-by: Alexander Graf --- arch/powerpc/include/asm/kvm_ppc.h | 6 ++++++ arch/powerpc/kvm/book3s_pr.c | 14 ++++++-------- arch/powerpc/kvm/booke.c | 12 +++++------- arch/powerpc/kvm/powerpc.c | 26 +++++++++----------------- 4 files changed, 26 insertions(+), 32 deletions(-) diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h index 629277df4798..fcd53f0d34ba 100644 --- a/arch/powerpc/include/asm/kvm_ppc.h +++ b/arch/powerpc/include/asm/kvm_ppc.h @@ -456,6 +456,12 @@ 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 aedba681bb94..e82fafdaf880 100644 --- a/arch/powerpc/kvm/book3s_pr.c +++ b/arch/powerpc/kvm/book3s_pr.c @@ -999,14 +999,14 @@ int kvmppc_handle_exit_pr(struct kvm_run *run, struct kvm_vcpu *vcpu, * 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 { + /* interrupts now hard-disabled */ kvmppc_fix_ee_before_entry(); } + kvmppc_handle_lost_ext(vcpu); } @@ -1219,12 +1219,10 @@ static int kvmppc_vcpu_run_pr(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; - } + /* interrupts now hard-disabled */ /* Save FPU state in thread_struct */ if (current->thread.regs->msr & MSR_FP) diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c index 6a8c32ec4173..07b89c711898 100644 --- a/arch/powerpc/kvm/booke.c +++ b/arch/powerpc/kvm/booke.c @@ -643,7 +643,7 @@ int kvmppc_core_prepare_to_enter(struct kvm_vcpu *vcpu) local_irq_enable(); kvm_vcpu_block(vcpu); clear_bit(KVM_REQ_UNHALT, &vcpu->requests); - local_irq_disable(); + hard_irq_disable(); kvmppc_set_exit_type(vcpu, EMULATED_MTMSRWE_EXITS); r = 1; @@ -688,13 +688,12 @@ 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; } + /* interrupts now hard-disabled */ #ifdef CONFIG_PPC_FPU /* Save userspace FPU state in stack */ @@ -1187,12 +1186,11 @@ 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 { + /* interrupts now hard-disabled */ kvmppc_fix_ee_before_entry(); } } diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c index 026dfaaa4772..3cf541a53e2a 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -68,14 +68,16 @@ int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu) */ int kvmppc_prepare_to_enter(struct kvm_vcpu *vcpu) { - int r = 1; + int r; + + WARN_ON(irqs_disabled()); + hard_irq_disable(); - WARN_ON_ONCE(!irqs_disabled()); while (true) { if (need_resched()) { local_irq_enable(); cond_resched(); - local_irq_disable(); + hard_irq_disable(); continue; } @@ -101,7 +103,7 @@ 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; @@ -113,22 +115,12 @@ int kvmppc_prepare_to_enter(struct kvm_vcpu *vcpu) continue; } -#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; - } -#endif - kvm_guest_enter(); - break; + return 1; } + /* return to host */ + local_irq_enable(); return r; } EXPORT_SYMBOL_GPL(kvmppc_prepare_to_enter); -- GitLab