Re: [PATCH v2 8/8] KVM: arm/arm64: register DEOI irq bypass consumer on ARM/ARM64

Christoffer Dall
2017-07-21T13:24:15Z

On Thu, Jun 15, 2017 at 02:52:40PM +0200, Eric Auger wrote:
> This patch selects IRQ_BYPASS_MANAGER and HAVE_KVM_IRQ_BYPASS
> configs for ARM/ARM64.
>
> kvm_arch_has_irq_bypass() now is implemented and returns true.
> As a consequence the irq bypass consumer will be registered for
> ARM/ARM64 with Direct EOI/IRQ forwarding callbacks:
>
> - stop/start: halt/resume guest execution
> - add/del_producer: set/unset forwarding/DEOI at vgic/irqchip level
>
> The consumer currently only works with a VFIO_PLATFORM producer.
> In other cases, start/stop do nothing and return without error
> to avoid outputting a spurious warning.
>
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>
> ---
>
> v1 -> v2:
> - check the type of the producer to avoid attachement with VFIO-PCI
> dummy MSI producer
> ---
> arch/arm/kvm/Kconfig | 3 +++
> arch/arm64/kvm/Kconfig | 3 +++
> virt/kvm/arm/arm.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 54 insertions(+)
>
> diff --git a/arch/arm/kvm/Kconfig b/arch/arm/kvm/Kconfig
> index 90d0176..4e2b192 100644
> --- a/arch/arm/kvm/Kconfig
> +++ b/arch/arm/kvm/Kconfig
> @@ -3,6 +3,7 @@
> #
>
> source "virt/kvm/Kconfig"
> +source "virt/lib/Kconfig"
>
> menuconfig VIRTUALIZATION
> bool "Virtualization"
> @@ -35,6 +36,8 @@ config KVM
> select HAVE_KVM_IRQCHIP
> select HAVE_KVM_IRQ_ROUTING
> select HAVE_KVM_MSI
> + select IRQ_BYPASS_MANAGER
> + select HAVE_KVM_IRQ_BYPASS
> depends on ARM_VIRT_EXT && ARM_LPAE && ARM_ARCH_TIMER
> ---help---
> Support hosting virtualized guest machines.
> diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
> index 52cb7ad..7e0d6e6 100644
> --- a/arch/arm64/kvm/Kconfig
> +++ b/arch/arm64/kvm/Kconfig
> @@ -3,6 +3,7 @@
> #
>
> source "virt/kvm/Kconfig"
> +source "virt/lib/Kconfig"
>
> menuconfig VIRTUALIZATION
> bool "Virtualization"
> @@ -35,6 +36,8 @@ config KVM
> select HAVE_KVM_MSI
> select HAVE_KVM_IRQCHIP
> select HAVE_KVM_IRQ_ROUTING
> + select IRQ_BYPASS_MANAGER
> + select HAVE_KVM_IRQ_BYPASS
> ---help---
> Support hosting virtualized guest machines.
> We don't support KVM with 16K page tables yet, due to the multiple
> diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
> index 3417e18..58871f8 100644
> --- a/virt/kvm/arm/arm.c
> +++ b/virt/kvm/arm/arm.c
> @@ -27,6 +27,8 @@
> #include <linux/mman.h>
> #include <linux/sched.h>
> #include <linux/kvm.h>
> +#include <linux/kvm_irqfd.h>
> +#include <linux/irqbypass.h>
> #include <trace/events/kvm.h>
> #include <kvm/arm_pmu.h>
>
> @@ -1420,6 +1422,52 @@ struct kvm_vcpu *kvm_mpidr_to_vcpu(struct kvm *kvm, unsigned long mpidr)
> return NULL;
> }
>
> +bool kvm_arch_has_irq_bypass(void)
> +{
> + return true;
> +}
> +
> +int kvm_arch_irq_bypass_add_producer(struct irq_bypass_consumer *cons,
> + struct irq_bypass_producer *prod)
> +{
> + struct kvm_kernel_irqfd *irqfd =
> + container_of(cons, struct kvm_kernel_irqfd, consumer);
> +
> + if (prod->type != IRQ_BYPASS_VFIO_PLATFORM)
> + 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)
> +{
> + struct kvm_kernel_irqfd *irqfd =
> + container_of(cons, struct kvm_kernel_irqfd, consumer);
> +
> + if (prod->type != IRQ_BYPASS_VFIO_PLATFORM)
> + return;
> +
> + kvm_vgic_unset_forwarding(irqfd->kvm, prod->irq,
> + irqfd->gsi + VGIC_NR_PRIVATE_IRQS);
> +}
> +
> +void kvm_arch_irq_bypass_stop(struct irq_bypass_consumer *cons)
> +{
> + struct kvm_kernel_irqfd *irqfd =
> + container_of(cons, struct kvm_kernel_irqfd, consumer);
> +
> + kvm_arm_halt_guest(irqfd->kvm);
> +}
> +
> +void kvm_arch_irq_bypass_start(struct irq_bypass_consumer *cons)
> +{
> + struct kvm_kernel_irqfd *irqfd =
> + container_of(cons, struct kvm_kernel_irqfd, consumer);
> +
> + kvm_arm_resume_guest(irqfd->kvm);
> +}
> +
> /**
> * Initialize Hyp-mode and memory mappings on all CPUs.
> */
> --
> 2.5.5

Nit: I'm wondering if this should go in a different file, like
virt/kvm/arm/irqbypass.c, or virt/kvm/arm/vgic/vgic-irqbypass.c ?

Thanks,
-Christoffer