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[78.232.41.119]) by mx.google.com with ESMTPSA id a6sm1695350wiy.17.2015.03.19.07.58.47 (version=TLSv1.1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 19 Mar 2015 07:58:48 -0700 (PDT) From: Eric Auger To: eric.auger@st.com, eric.auger@linaro.org, christoffer.dall@linaro.org, marc.zyngier@arm.com, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, alex.williamson@redhat.com Cc: linux-kernel@vger.kernel.org, patches@linaro.org, pbonzini@redhat.com, kim.phillips@freescale.com, b.reynal@virtualopensystems.com, feng.wu@intel.com Subject: [RFC v5 13/13] KVM: arm/arm64: vgic: forwarding control Date: Thu, 19 Mar 2015 15:55:51 +0100 Message-Id: <1426776951-24901-14-git-send-email-eric.auger@linaro.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1426776951-24901-1-git-send-email-eric.auger@linaro.org> References: <1426776951-24901-1-git-send-email-eric.auger@linaro.org> X-Removed-Original-Auth: Dkim didn't pass. X-Original-Sender: eric.auger@linaro.org X-Original-Authentication-Results: mx.google.com; spf=pass (google.com: domain of patch+caf_=patchwork-forward=linaro.org@linaro.org designates 209.85.215.44 as permitted sender) smtp.mail=patch+caf_=patchwork-forward=linaro.org@linaro.org Precedence: list Mailing-list: list patchwork-forward@linaro.org; contact patchwork-forward+owners@linaro.org List-ID: X-Google-Group-Id: 836684582541 List-Post: , List-Help: , List-Archive: List-Unsubscribe: , This patch sets __KVM_HAVE_ARCH_KVM_VFIO_FORWARD and implements kvm_arch_set_forward for ARM/ARM64. As a result the KVM-VFIO device now allows to forward/unforward a VFIO device IRQ on ARM. kvm_arch_set_forward and kvm_arch_unset_forward mostly take care of VGIC programming: physical IRQ/guest IRQ mapping, list register cleanup, VGIC state machine. Signed-off-by: Eric Auger --- v4 -> v5: - fix arm64 compilation issues, ie. also defines __KVM_HAVE_ARCH_HALT_GUEST for arm64 v3 -> v4: - code originally located in kvm_vfio_arm.c - kvm_arch_vfio_{set|unset}_forward renamed into kvm_arch_{set|unset}_forward - split into 2 functions (set/unset) since unset does not fail anymore - unset can be invoked at whatever time. Extra care is taken to handle transition in VGIC state machine, LR cleanup, ... v2 -> v3: - renaming of kvm_arch_set_fwd_state into kvm_arch_vfio_set_forward - takes a bool arg instead of kvm_fwd_irq_action enum - removal of KVM_VFIO_IRQ_CLEANUP - platform device check now happens here - more precise errors returned - irq_eoi handled externally to this patch (VGIC) - correct enable_irq bug done twice - reword the commit message - correct check of platform_bus_type - use raw_spin_lock_irqsave and check the validity of the handler --- arch/arm/include/asm/kvm_host.h | 1 + arch/arm64/include/asm/kvm_host.h | 1 + virt/kvm/arm/vgic.c | 190 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 192 insertions(+) diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h index b829f93..8e3fd7f 100644 --- a/arch/arm/include/asm/kvm_host.h +++ b/arch/arm/include/asm/kvm_host.h @@ -29,6 +29,7 @@ #define __KVM_HAVE_ARCH_INTC_INITIALIZED #define __KVM_HAVE_ARCH_HALT_GUEST +#define __KVM_HAVE_ARCH_KVM_VFIO_FORWARD #if defined(CONFIG_KVM_ARM_MAX_VCPUS) #define KVM_MAX_VCPUS CONFIG_KVM_ARM_MAX_VCPUS diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index ffcc698..9be392a 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -30,6 +30,7 @@ #define __KVM_HAVE_ARCH_INTC_INITIALIZED #define __KVM_HAVE_ARCH_HALT_GUEST +#define __KVM_HAVE_ARCH_KVM_VFIO_FORWARD #if defined(CONFIG_KVM_ARM_MAX_VCPUS) #define KVM_MAX_VCPUS CONFIG_KVM_ARM_MAX_VCPUS diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c index cc9ff63..8a396f9 100644 --- a/virt/kvm/arm/vgic.c +++ b/virt/kvm/arm/vgic.c @@ -2117,3 +2117,193 @@ int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e, { return 0; } + +/** + * kvm_arch_set_forward - Set forwarding for a given IRQ + * + * @kvm: handle to the VM + * @host_irq: physical IRQ number + * @guest_irq: virtual IRQ number + * + * This function is supposed to be called only if the IRQ + * is not in progress: ie. not active at VGIC level and not + * currently under injection in the KVM. + */ +int kvm_arch_set_forward(struct kvm *kvm, unsigned int host_irq, + unsigned int guest_irq) +{ + irq_hw_number_t gic_irq; + struct irq_desc *desc = irq_to_desc(host_irq); + struct irq_data *d; + unsigned long flags; + struct kvm_vcpu *vcpu = kvm_get_vcpu(kvm, 0); + int ret = 0; + int spi_id = guest_irq + VGIC_NR_PRIVATE_IRQS; + struct vgic_dist *dist = &kvm->arch.vgic; + + if (!vcpu) + return 0; + + spin_lock(&dist->lock); + + raw_spin_lock_irqsave(&desc->lock, flags); + d = &desc->irq_data; + gic_irq = irqd_to_hwirq(d); + irqd_set_irq_forwarded(d); + /* + * next physical IRQ will be be handled as forwarded + * by the host (priority drop only) + */ + + raw_spin_unlock_irqrestore(&desc->lock, flags); + + /* + * need to release the dist spin_lock here since + * vgic_map_phys_irq can sleep + */ + spin_unlock(&dist->lock); + ret = vgic_map_phys_irq(vcpu, spi_id, (int)gic_irq); + /* + * next guest_irq injection will be considered as + * forwarded and next flush will program LR + * without maintenance IRQ but with HW bit set + */ + return ret; +} + +/** + * kvm_arch_unset_forward - Unset forwarding for a given IRQ + * + * @kvm: handle to the VM + * @host_irq: physical IRQ number + * @guest_irq: virtual IRQ number + * @active: returns whether the physical IRQ is active + * + * This function must be called when the host_irq is disabled + * and guest has been exited and prevented from being re-entered. + * + */ +void kvm_arch_unset_forward(struct kvm *kvm, + unsigned int host_irq, + unsigned int guest_irq, + bool *active) +{ + struct kvm_vcpu *vcpu = kvm_get_vcpu(kvm, 0); + struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu; + struct vgic_dist *dist = &kvm->arch.vgic; + int ret, lr; + struct vgic_lr vlr; + struct irq_desc *desc = irq_to_desc(host_irq); + struct irq_data *d; + unsigned long flags; + irq_hw_number_t gic_irq; + int spi_id = guest_irq + VGIC_NR_PRIVATE_IRQS; + struct irq_chip *chip; + bool queued, needs_deactivate = true; + + spin_lock(&dist->lock); + + irq_get_irqchip_state(host_irq, IRQCHIP_STATE_ACTIVE, active); + + if (!vcpu) + goto out; + + raw_spin_lock_irqsave(&desc->lock, flags); + d = irq_desc_get_irq_data(desc); + gic_irq = irqd_to_hwirq(d); + raw_spin_unlock_irqrestore(&desc->lock, flags); + + ret = vgic_unmap_phys_irq(vcpu, spi_id, gic_irq); + /* + * subsequent update_irq_pending or flush will handle this + * irq as forwarded + */ + + if (likely(!(*active))) { + /* + * the IRQ was not active. It may happen the handle_fasteoi_irq + * is entered afterwards due to lazy disable_irq. If this + * happens the IRQ will be deactivated and never be injected. + * let's simply prepare the states for subsequent non forwarded + * injection + */ + vgic_dist_irq_clear_level(vcpu, spi_id); + vgic_dist_irq_clear_pending(vcpu, spi_id); + vgic_irq_clear_queued(vcpu, spi_id); + needs_deactivate = false; + goto out; + } + + /* is there any list register with valid state? */ + lr = vgic_cpu->vgic_irq_lr_map[spi_id]; + queued = false; + if (lr != LR_EMPTY) { + vlr = vgic_get_lr(vcpu, lr); + if (vlr.state & LR_STATE_MASK) + queued = true; + } + + if (!queued) { + vgic_irq_clear_queued(vcpu, spi_id); + if (vgic_dist_irq_is_pending(vcpu, spi_id)) { + /* + * IRQ is injected but not yet queued. LR will be + * written with EOI_INT and process_maintenance will + * reset the states: queued, level(resampler). Pending + * will be reset on flush. + */ + vgic_dist_irq_set_level(vcpu, spi_id); + } else { + /* + * We are before the injection (update_irq_pending). + * This is the most tricky window. Due to the usage of + * disable_irq in generic unforward part (mandated by + * resamplefd unmask VFIO integration), there is a risk + * the fasteoi handler returns without calling the VFIO + * handler and deactivates the physical IRQ (lazy + * disable). Hence we cannot know whether the IRQ will + * ever be injected. The only solution found is to do as + * if the IRQ were not active. The active parameter + * typically is used by the caller to know whether + * it needs to mask * the IRQ. If not duly masked, + * another physical IRQ may hit again while the previous + * virtual IRQ is in progress. Update_irq_pending + * validate_injection will prevent this injection. + */ + vgic_dist_irq_clear_level(vcpu, spi_id); + *active = false; + } + goto out; + } + + /* + * the virtual IRQ is queued and a valid LR exists, let's patch it for + * EOI maintenance + */ + vlr.state |= LR_EOI_INT; + vgic_set_lr(vcpu, lr, vlr); + /* + * we expect a maintenance IRQ which will reset the + * queued, pending and level states + */ + vgic_dist_irq_set_level(vcpu, spi_id); + vgic_dist_irq_set_pending(vcpu, spi_id); + vgic_irq_set_queued(vcpu, spi_id); + +out: + + raw_spin_lock_irqsave(&desc->lock, flags); + d = irq_desc_get_irq_data(desc); + if (needs_deactivate) { + chip = irq_data_get_irq_chip(d); + chip->irq_eoi(d); + } + irqd_clr_irq_forwarded(d); + /* next occurrence will be deactivated by the host */ + raw_spin_unlock_irqrestore(&desc->lock, flags); + + *active = *active && vcpu; + + spin_unlock(&dist->lock); +} +