From patchwork Mon Aug 13 01:21:34 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Graf X-Patchwork-Id: 176847 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 56FC22C0091 for ; Mon, 13 Aug 2012 11:21:52 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752912Ab2HMBVs (ORCPT ); Sun, 12 Aug 2012 21:21:48 -0400 Received: from cantor2.suse.de ([195.135.220.15]:53405 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752447Ab2HMBVl (ORCPT ); Sun, 12 Aug 2012 21:21:41 -0400 Received: from relay1.suse.de (unknown [195.135.220.254]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mx2.suse.de (Postfix) with ESMTP id C2C40A398D; Mon, 13 Aug 2012 03:21:40 +0200 (CEST) From: Alexander Graf To: kvm-ppc@vger.kernel.org Cc: KVM list Subject: [PATCH 09/10] KVM: PPC: Book3S: PR: Rework irq disabling Date: Mon, 13 Aug 2012 03:21:34 +0200 Message-Id: <1344820895-8475-10-git-send-email-agraf@suse.de> X-Mailer: git-send-email 1.6.0.2 In-Reply-To: <1344820895-8475-1-git-send-email-agraf@suse.de> References: <1344820895-8475-1-git-send-email-agraf@suse.de> Sender: kvm-ppc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm-ppc@vger.kernel.org Today, we disable preemption while inside guest context, because we need to expose to the world that we are not in a preemptible context. However, during that time we already have interrupts disabled, which would indicate that we are in a non-preemptible context. The reason the checks for irqs_disabled() fail for us though is that we manually control hard IRQs and ignore all the lazy EE framework. Let's stop doing that. Instead, let's always use lazy EE to indicate when we want to disable IRQs, but do a special final switch that gets us into EE disabled, but soft enabled state. That way when we get back out of guest state, we are immediately ready to process interrupts. This simplifies the code drastically and reduces the time that we appear as preempt disabled. Signed-off-by: Alexander Graf --- arch/powerpc/include/asm/kvm_ppc.h | 10 ++++++++++ arch/powerpc/kvm/book3s_pr.c | 21 +++++++-------------- arch/powerpc/kvm/book3s_rmhandlers.S | 15 ++++++++------- arch/powerpc/kvm/booke.c | 2 ++ arch/powerpc/kvm/powerpc.c | 14 ++++++++++++++ 5 files changed, 41 insertions(+), 21 deletions(-) diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h index 59b7c87..5459364 100644 --- a/arch/powerpc/include/asm/kvm_ppc.h +++ b/arch/powerpc/include/asm/kvm_ppc.h @@ -234,5 +234,15 @@ static inline void kvmppc_mmu_flush_icache(pfn_t pfn) } } +/* Please call after prepare_to_enter. This function puts the lazy ee state + back to normal mode, without actually enabling interrupts. */ +static inline void kvmppc_lazy_ee_enable(void) +{ +#ifdef CONFIG_PPC64 + /* Only need to enable IRQs by hard enabling them after this */ + local_paca->irq_happened = 0; + local_paca->soft_enabled = 1; +#endif +} #endif /* __POWERPC_KVM_PPC_H__ */ diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c index 3e6ad89..203f3b2 100644 --- a/arch/powerpc/kvm/book3s_pr.c +++ b/arch/powerpc/kvm/book3s_pr.c @@ -52,8 +52,6 @@ static int kvmppc_handle_ext(struct kvm_vcpu *vcpu, unsigned int exit_nr, #define MSR_USER32 MSR_USER #define MSR_USER64 MSR_USER #define HW_PAGE_SIZE PAGE_SIZE -#define __hard_irq_disable local_irq_disable -#define __hard_irq_enable local_irq_enable #endif void kvmppc_core_vcpu_load(struct kvm_vcpu *vcpu, int cpu) @@ -599,12 +597,10 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu, run->exit_reason = KVM_EXIT_UNKNOWN; run->ready_for_interrupt_injection = 1; - /* We get here with MSR.EE=0, so enable it to be a nice citizen */ - __hard_irq_enable(); + /* We get here with MSR.EE=1 */ trace_kvm_exit(exit_nr, vcpu); kvm_guest_exit(); - preempt_enable(); switch (exit_nr) { case BOOK3S_INTERRUPT_INST_STORAGE: @@ -856,7 +852,6 @@ program_interrupt: } } - preempt_disable(); if (!(r & RESUME_HOST)) { /* To avoid clobbering exit_reason, only check for signals if * we aren't already exiting to userspace for some other @@ -868,14 +863,15 @@ program_interrupt: * and if we really did time things so badly, then we just exit * again due to a host external interrupt. */ - __hard_irq_disable(); + local_irq_disable(); if (kvmppc_prepare_to_enter(vcpu)) { - /* local_irq_enable(); */ + local_irq_enable(); run->exit_reason = KVM_EXIT_INTR; r = -EINTR; } else { /* Going back to guest */ kvm_guest_enter(); + kvmppc_lazy_ee_enable(); } } @@ -1068,8 +1064,6 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu) #endif ulong ext_msr; - preempt_disable(); - /* Check if we can run the vcpu at all */ if (!vcpu->arch.sane) { kvm_run->exit_reason = KVM_EXIT_INTERNAL_ERROR; @@ -1083,9 +1077,9 @@ 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. */ - __hard_irq_disable(); + local_irq_disable(); if (kvmppc_prepare_to_enter(vcpu)) { - __hard_irq_enable(); + local_irq_enable(); kvm_run->exit_reason = KVM_EXIT_INTR; ret = -EINTR; goto out; @@ -1124,7 +1118,7 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu) if (vcpu->arch.shared->msr & MSR_FP) kvmppc_handle_ext(vcpu, BOOK3S_INTERRUPT_FP_UNAVAIL, MSR_FP); - kvm_guest_enter(); + kvmppc_lazy_ee_enable(); ret = __kvmppc_vcpu_run(kvm_run, vcpu); @@ -1159,7 +1153,6 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu) out: vcpu->mode = OUTSIDE_GUEST_MODE; - preempt_enable(); return ret; } diff --git a/arch/powerpc/kvm/book3s_rmhandlers.S b/arch/powerpc/kvm/book3s_rmhandlers.S index 9ecf6e3..b2f8258 100644 --- a/arch/powerpc/kvm/book3s_rmhandlers.S +++ b/arch/powerpc/kvm/book3s_rmhandlers.S @@ -170,20 +170,21 @@ kvmppc_handler_skip_ins: * Call kvmppc_handler_trampoline_enter in real mode * * On entry, r4 contains the guest shadow MSR + * MSR.EE has to be 0 when calling this function */ _GLOBAL(kvmppc_entry_trampoline) mfmsr r5 LOAD_REG_ADDR(r7, kvmppc_handler_trampoline_enter) toreal(r7) - li r9, MSR_RI - ori r9, r9, MSR_EE - andc r9, r5, r9 /* Clear EE and RI in MSR value */ li r6, MSR_IR | MSR_DR - ori r6, r6, MSR_EE - andc r6, r5, r6 /* Clear EE, DR and IR in MSR value */ - MTMSR_EERI(r9) /* Clear EE and RI in MSR */ - mtsrr0 r7 /* before we set srr0/1 */ + andc r6, r5, r6 /* Clear DR and IR in MSR value */ + /* + * Set EE in HOST_MSR so that it's enabled when we get into our + * C exit handler function + */ + ori r5, r5, MSR_EE + mtsrr0 r7 mtsrr1 r6 RFI diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c index aae535f..2bd190c 100644 --- a/arch/powerpc/kvm/booke.c +++ b/arch/powerpc/kvm/booke.c @@ -486,6 +486,7 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu) ret = -EINTR; goto out; } + kvmppc_lazy_ee_enable(); kvm_guest_enter(); @@ -955,6 +956,7 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu, } else { /* Going back to guest */ kvm_guest_enter(); + kvmppc_lazy_ee_enable(); } } diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c index 87648bd..ce9c7da 100644 --- a/arch/powerpc/kvm/powerpc.c +++ b/arch/powerpc/kvm/powerpc.c @@ -30,6 +30,7 @@ #include #include #include +#include #include "timing.h" #include "../mm/mmu_decl.h" @@ -93,6 +94,19 @@ int kvmppc_prepare_to_enter(struct kvm_vcpu *vcpu) break; } +#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(); + continue; + } + + trace_hardirqs_on(); +#endif + /* Going into guest context! Yay! */ vcpu->mode = IN_GUEST_MODE; smp_wmb();