Hi Marc, On 30/08/2017 12:42, Marc Zyngier wrote: > Hi Eric, > > On 30/08/17 11:20, Auger Eric wrote: >> Hi Marc, >> >> On 30/08/2017 11:42, 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, >>>>> + }; >>>>> + >>>>> + if (its_map_vlpi(virq, &map)) >>>>> + goto out; >>>> >>>> This seems to be able to return things like -ENOMEM, whould we really >>>> not report this back to the caller in any way? >>> >>> >>> That's a good question. >>> >>> If we return -ENOMEM, we'll probably end-up returning an error to >>> userspace (as a result of the VFIO ioctl), which will in turn probably >>> terminate the guest (I'm guessing, I haven't actually looked at what >>> userspace does). >>> >>> If we don't return the error, then we have a chance to keep the guest >>> running by sticking to software injection. >> I have not read the whole stuff yet but userspace is not aware of this >> negotiation. Everything happens under the hood in kernel, see >> virt/lib/irqbypass.c __connect(): if add_producer() fails >> prod->del_consumer() is called and we should return to the not optimized >> injection. > > Ah, fair enough. I guess del_consumer() does nothing on PCI?
Correct. For vfio-platform, it is switching back to automasked handler but if you haven't implemented anything specific on vfio side in this series, it is not even implemented. Thanks Eric > > Thanks, > > M. >
