From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marc Zyngier Subject: Re: [PATCH v3 41/59] KVM: arm/arm64: GICv4: Wire mapping/unmapping of VLPIs in VFIO irq bypass Date: Wed, 30 Aug 2017 13:53:30 +0100 Message-ID: <9fc83ca2-bdae-ffbc-9d81-c77c331b47d2@arm.com> References: <20170731172637.29355-1-marc.zyngier@arm.com> <20170731172637.29355-42-marc.zyngier@arm.com> <20170826194850.GB11074@cbox> <06930ddb-6c40-ff74-0062-cec236ce2455@arm.com> <20170830114646.GD24522@cbox> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Jason Cooper , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Thomas Gleixner , kvmarm@lists.cs.columbia.edu To: Christoffer Dall Return-path: In-Reply-To: <20170830114646.GD24522@cbox> Content-Language: en-GB List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu List-Id: kvm.vger.kernel.org On 30/08/17 12:46, Christoffer Dall wrote: > On Wed, Aug 30, 2017 at 11:28:08AM +0100, Marc Zyngier wrote: >> On 26/08/17 20:48, Christoffer Dall wrote: >>> On Mon, Jul 31, 2017 at 06:26:19PM +0100, Marc Zyngier wrote: >>>> Let's use the irq bypass mechanism introduced for platform device >>>> interrupts to intercept the virtual PCIe endpoint configuration >>>> and establish our LPI->VLPI mapping. >>>> >>>> Signed-off-by: Marc Zyngier >>>> --- >>>> include/kvm/arm_vgic.h | 8 ++++ >>>> virt/kvm/arm/arm.c | 27 ++++++++---- >>>> virt/kvm/arm/vgic/vgic-v4.c | 103 ++++++++++++++++++++++++++++++++++++++++++++ >>>> 3 files changed, 130 insertions(+), 8 deletions(-) >>>> >>>> diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h >>>> index 359eeffe9857..050f78d4fb42 100644 >>>> --- a/include/kvm/arm_vgic.h >>>> +++ b/include/kvm/arm_vgic.h >>>> @@ -367,4 +367,12 @@ int kvm_vgic_set_forwarding(struct kvm *kvm, unsigned int host_irq, >>>> void kvm_vgic_unset_forwarding(struct kvm *kvm, unsigned int host_irq, >>>> unsigned int vintid); >>>> >>>> +struct kvm_kernel_irq_routing_entry; >>>> + >>>> +int kvm_vgic_v4_set_forwarding(struct kvm *kvm, int irq, >>>> + struct kvm_kernel_irq_routing_entry *irq_entry); >>>> + >>>> +int kvm_vgic_v4_unset_forwarding(struct kvm *kvm, int irq, >>>> + struct kvm_kernel_irq_routing_entry *irq_entry); >>>> + >>>> #endif /* __KVM_ARM_VGIC_H */ >>>> diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c >>>> index ebab6c29e3be..6803ea27c47d 100644 >>>> --- a/virt/kvm/arm/arm.c >>>> +++ b/virt/kvm/arm/arm.c >>>> @@ -1457,11 +1457,16 @@ int kvm_arch_irq_bypass_add_producer(struct irq_bypass_consumer *cons, >>>> struct kvm_kernel_irqfd *irqfd = >>>> container_of(cons, struct kvm_kernel_irqfd, consumer); >>>> >>>> - if (prod->type != IRQ_BYPASS_VFIO_PLATFORM) >>>> + switch (prod->type) { >>>> + case IRQ_BYPASS_VFIO_PLATFORM: >>>> + return kvm_vgic_set_forwarding(irqfd->kvm, prod->irq, >>>> + irqfd->gsi + VGIC_NR_PRIVATE_IRQS); >>>> + case IRQ_BYPASS_VFIO_PCI_MSI: >>>> + return kvm_vgic_v4_set_forwarding(irqfd->kvm, prod->irq, >>>> + &irqfd->irq_entry); >>>> + default: >>>> return 0; >>>> - >>>> - return kvm_vgic_set_forwarding(irqfd->kvm, prod->irq, >>>> - irqfd->gsi + VGIC_NR_PRIVATE_IRQS); >>>> + } >>>> } >>>> void kvm_arch_irq_bypass_del_producer(struct irq_bypass_consumer *cons, >>>> struct irq_bypass_producer *prod) >>>> @@ -1469,11 +1474,17 @@ void kvm_arch_irq_bypass_del_producer(struct irq_bypass_consumer *cons, >>>> struct kvm_kernel_irqfd *irqfd = >>>> container_of(cons, struct kvm_kernel_irqfd, consumer); >>>> >>>> - if (prod->type != IRQ_BYPASS_VFIO_PLATFORM) >>>> - return; >>>> + switch (prod->type) { >>>> + case IRQ_BYPASS_VFIO_PLATFORM: >>>> + kvm_vgic_unset_forwarding(irqfd->kvm, prod->irq, >>>> + irqfd->gsi + VGIC_NR_PRIVATE_IRQS); >>>> + break; >>>> >>>> - kvm_vgic_unset_forwarding(irqfd->kvm, prod->irq, >>>> - irqfd->gsi + VGIC_NR_PRIVATE_IRQS); >>>> + case IRQ_BYPASS_VFIO_PCI_MSI: >>>> + kvm_vgic_v4_unset_forwarding(irqfd->kvm, prod->irq, >>>> + &irqfd->irq_entry); >>>> + break; >>>> + } >>>> } >>>> >>>> void kvm_arch_irq_bypass_stop(struct irq_bypass_consumer *cons) >>>> diff --git a/virt/kvm/arm/vgic/vgic-v4.c b/virt/kvm/arm/vgic/vgic-v4.c >>>> index 207e1fda0dcd..338c86c5159f 100644 >>>> --- a/virt/kvm/arm/vgic/vgic-v4.c >>>> +++ b/virt/kvm/arm/vgic/vgic-v4.c >>>> @@ -72,3 +72,106 @@ void vgic_v4_teardown(struct kvm *kvm) >>>> its_vm->nr_vpes = 0; >>>> its_vm->vpes = NULL; >>>> } >>>> + >>>> +static struct vgic_its *vgic_get_its(struct kvm *kvm, >>>> + struct kvm_kernel_irq_routing_entry *irq_entry) >>>> +{ >>>> + struct kvm_msi msi = (struct kvm_msi) { >>>> + .address_lo = irq_entry->msi.address_lo, >>>> + .address_hi = irq_entry->msi.address_hi, >>>> + .data = irq_entry->msi.data, >>>> + .flags = irq_entry->msi.flags, >>>> + .devid = irq_entry->msi.devid, >>>> + }; >>>> + >>>> + /* >>>> + * Get a reference on the LPI. If NULL, this is not a valid >>>> + * translation for any of our vITSs. >>>> + */ >>>> + return vgic_msi_to_its(kvm, &msi); >>>> +} >>>> + >>>> +int kvm_vgic_v4_set_forwarding(struct kvm *kvm, int virq, >>>> + struct kvm_kernel_irq_routing_entry *irq_entry) >>>> +{ >>>> + struct vgic_its *its; >>>> + struct vgic_irq *irq; >>>> + struct its_vlpi_map map; >>>> + int ret; >>>> + >>>> + if (!vgic_is_v4_capable(kvm)) >>>> + return 0; >>>> + >>>> + /* >>>> + * Get the ITS, and escape early on error (not a valid >>>> + * doorbell for any of our vITSs). >>>> + */ >>>> + its = vgic_get_its(kvm, irq_entry); >>>> + if (IS_ERR(its)) >>>> + return 0; >>>> + >>>> + mutex_lock(&its->its_lock); >>>> + >>>> + /* Perform then actual DevID/EventID -> LPI translation. */ >>>> + ret = vgic_its_resolve_lpi(kvm, its, irq_entry->msi.devid, >>>> + irq_entry->msi.data, &irq); >>>> + if (ret) >>>> + goto out; >>>> + >>>> + /* >>>> + * Emit the mapping request. If it fails, the ITS probably >>>> + * isn't v4 compatible, so let's silently bail out. Holding >>>> + * the ITS lock should ensure that nothing can modify the >>>> + * target vcpu. >>>> + */ >>>> + map = (struct its_vlpi_map) { >>>> + .vm = &kvm->arch.vgic.its_vm, >>>> + .vintid = irq->intid, >>>> + .db_enabled = true, >>>> + .vpe_idx = irq->target_vcpu->vcpu_id, >> >> This is just wrong. We cannot assume that the vcpu_id has anything to do >> with the vpe_idx. It happens to be the same thing now, but the two things >> should be clearly disconnected. >> >> I suggest the following (untested): >> >> diff --git a/virt/kvm/arm/vgic/vgic-v4.c b/virt/kvm/arm/vgic/vgic-v4.c >> index cf5d6e2de6b8..0146e004401a 100644 >> --- a/virt/kvm/arm/vgic/vgic-v4.c >> +++ b/virt/kvm/arm/vgic/vgic-v4.c >> @@ -251,13 +251,27 @@ static void dump_routing(int virq, struct kvm_kernel_irq_routing_entry *irq_entr >> >> } >> >> +static int vgic_v4_vcpu_to_index(struct its_vm *its_vm, struct kvm_vcpu *vcpu) >> +{ >> + int i; >> + >> + for (i = 0; i < its_vm->nr_vpes; i++) { >> + struct its_vpe *vpe = &vcpu->arch.vgic_cpu.vgic_v3.its_vpe; >> + >> + if (its_vm->vpes[i] == vpe) >> + return i; >> + } >> + >> + return -ENODEV; >> +} >> + > > Stupid question: Can we change the struct its_vlpi_map to contain a > vpe pointer or in stead of or in addition to the index? This is obviously the right solution, because the *index* of the VPE doesn't really matter for a map/unmap (it only matters for doorbell operations, and that's a very different code path). I came up with the following (untested, again), which is much more appealing: diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c index b47097a3e4b4..0607541fcafc 100644 --- a/drivers/irqchip/irq-gic-v3-its.c +++ b/drivers/irqchip/irq-gic-v3-its.c @@ -900,7 +900,7 @@ static void its_send_vmapti(struct its_device *dev, u32 id) struct its_vlpi_map *map = &dev->event_map.vlpi_maps[id]; struct its_cmd_desc desc; - desc.its_vmapti_cmd.vpe = map->vm->vpes[map->vpe_idx]; + desc.its_vmapti_cmd.vpe = map->vpe; desc.its_vmapti_cmd.dev = dev; desc.its_vmapti_cmd.virt_id = map->vintid; desc.its_vmapti_cmd.event_id = id; @@ -914,7 +914,7 @@ static void its_send_vmovi(struct its_device *dev, u32 id) struct its_vlpi_map *map = &dev->event_map.vlpi_maps[id]; struct its_cmd_desc desc; - desc.its_vmovi_cmd.vpe = map->vm->vpes[map->vpe_idx]; + desc.its_vmovi_cmd.vpe = map->vpe; desc.its_vmovi_cmd.dev = dev; desc.its_vmovi_cmd.event_id = id; desc.its_vmovi_cmd.db_enabled = map->db_enabled; diff --git a/include/linux/irqchip/arm-gic-v4.h b/include/linux/irqchip/arm-gic-v4.h index 52661b838821..58a4d89aa82c 100644 --- a/include/linux/irqchip/arm-gic-v4.h +++ b/include/linux/irqchip/arm-gic-v4.h @@ -62,15 +62,15 @@ struct its_vpe { * irq_set_vcpu_affinity(). * * @vm: Pointer to the GICv4 notion of a VM + * @vpe: Pointer to the GICv4 notion of a virtual CPU (VPE) * @vintid: Virtual LPI number * @db_enabled: Is the VPE doorbell to be generated? - * @vpe_idx: Index (0-based) of the VPE in this VM. Not the vpe_id! */ struct its_vlpi_map { struct its_vm *vm; + struct its_vpe *vpe; u32 vintid; bool db_enabled; - u16 vpe_idx; }; enum its_vcpu_info_cmd_type { diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c index d790d0c74b8b..6ba3d73e0f70 100644 --- a/virt/kvm/arm/vgic/vgic-its.c +++ b/virt/kvm/arm/vgic/vgic-its.c @@ -715,7 +715,7 @@ static int vgic_its_cmd_handle_movi(struct kvm *kvm, struct vgic_its *its, if (ret) return ret; - map.vpe_idx = vcpu->vcpu_id; + map.vpe = &vcpu->arch.vgic_cpu.vgic_v3.its_vpe; return its_map_vlpi(ite->irq->host_irq, &map); } @@ -1184,7 +1184,7 @@ static int vgic_its_cmd_handle_movall(struct kvm *kvm, struct vgic_its *its, struct its_vlpi_map map; if (!its_get_vlpi(irq->host_irq, &map)) { - map.vpe_idx = vcpu2->vcpu_id; + map.vpe = &vcpu2->arch.vgic_cpu.vgic_v3.its_vpe; its_map_vlpi(irq->host_irq, &map); } } diff --git a/virt/kvm/arm/vgic/vgic-v4.c b/virt/kvm/arm/vgic/vgic-v4.c index cf5d6e2de6b8..6ece88322013 100644 --- a/virt/kvm/arm/vgic/vgic-v4.c +++ b/virt/kvm/arm/vgic/vgic-v4.c @@ -288,9 +288,9 @@ int kvm_vgic_v4_set_forwarding(struct kvm *kvm, int virq, */ map = (struct its_vlpi_map) { .vm = &kvm->arch.vgic.its_vm, + .vpe = &irq->target_vcpu->arch.vgic_cpu.vgic_v3.its_vpe, .vintid = irq->intid, .db_enabled = true, - .vpe_idx = irq->target_vcpu->vcpu_id, }; if (its_map_vlpi(virq, &map)) Maybe I'll introduce a vcpu_to_vpe() helper, but it already looks much better to me... Thanks, M. -- Jazz is not dead. It just smells funny...