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Message-ID: <20170826194850.GB11074@cbox>
Date: Sat, 26 Aug 2017 21:48:50 +0200
From: Christoffer Dall <cdall@...aro.org>
To: Marc Zyngier <marc.zyngier@....com>
Cc: linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
kvmarm@...ts.cs.columbia.edu, kvm@...r.kernel.org,
Christoffer Dall <christoffer.dall@...aro.org>,
Thomas Gleixner <tglx@...utronix.de>,
Jason Cooper <jason@...edaemon.net>,
Eric Auger <eric.auger@...hat.com>,
Shanker Donthineni <shankerd@...eaurora.org>,
Mark Rutland <mark.rutland@....com>,
Shameerali Kolothum Thodi
<shameerali.kolothum.thodi@...wei.com>
Subject: Re: [PATCH v3 41/59] KVM: arm/arm64: GICv4: Wire mapping/unmapping
of VLPIs in VFIO irq bypass
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 <marc.zyngier@....com>
> ---
> 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?
> +
> + irq->hw = true;
> + irq->host_irq = virq;
> +
> +out:
> + mutex_unlock(&its->its_lock);
> + return 0;
> +}
> +
> +int kvm_vgic_v4_unset_forwarding(struct kvm *kvm, int virq,
> + struct kvm_kernel_irq_routing_entry *irq_entry)
> +{
> + struct vgic_its *its;
> + struct vgic_irq *irq;
> + 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);
> +
> + ret = vgic_its_resolve_lpi(kvm, its, irq_entry->msi.devid,
> + irq_entry->msi.data, &irq);
> + if (ret)
> + goto out;
> +
> + WARN_ON(!(irq->hw && irq->host_irq == virq));
> + irq->hw = false;
> + ret = its_unmap_vlpi(virq);
> +
> +out:
> + mutex_unlock(&its->its_lock);
> + return ret;
> +}
> --
> 2.11.0
>
Otherwise looks good to me.
Thanks,
-Christoffer
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