On Thu, Aug 31, 2017 at 11:24:37AM +0100, Marc Zyngier wrote: > On 30/08/17 20:59, Christoffer Dall wrote: > > On Wed, Aug 30, 2017 at 01:53:30PM +0100, Marc Zyngier wrote: > >> 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 <[email protected]> > >>>>>> --- > >>>>>> 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... > >> > > Yes, indeed. Looks good to me as well. > > > > The only thing that makes me slightly nervous is the use of target_vcpu, > > but I think we rely on it never being NULL for LPIs elsewhere in the > > code, so we should be fine. > Hmmm. Maybe not. When mapping an LPI, you can assign it to a collection > that is not yet mapped to a redistributor, hence no target_vcpu.
Oh right, the local vcpu varible in ...handle_mapi is initialized to NULL, bummer I missed that. > > But in this case, vgic_its_resolve_lpi() fails, and we just don't enter > this code path. Annoyingly, this also shows that I do not handle MAPC at > all in this code, which is pretty embarrassing (I rely on MAPC being > done before MAPI/MAPTI). > > I'll address that in the next version. > Looking forward to it ;) -Christoffer
