Subject: [PATCH v3 10/11] KVM: arm/arm64: prepare GICv3 emulation to use kvm_io_bus MMIO handling

From: [email-masked] (Marc Zyngier)
Date: Thu, 26 Mar 2015 22:06:32 +0000

On Thu, 26 Mar 2015 14:39:37 +0000
Andre Przywara <[email-masked]> wrote:

> Using the framework provided by the recent vgic.c changes, we
> register a kvm_io_bus device on mapping the virtual GICv3 resources.
> The distributor mapping is pretty straight forward, but the
> redistributors need some more love, since they need to be tagged with
> the respective redistributor (read: VCPU) they are connected with.
> We use the kvm_io_bus framework to register one devices per VCPU.
> 
> Signed-off-by: Andre Przywara <[email-masked]>
> ---
>  include/kvm/arm_vgic.h      |    1 +
>  virt/kvm/arm/vgic-v3-emul.c |   39 ++++++++++++++++++++++++++++++++++++++-
>  2 files changed, 39 insertions(+), 1 deletion(-)
> 
> diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
> index 4523984..d6705f4 100644
> --- a/include/kvm/arm_vgic.h
> +++ b/include/kvm/arm_vgic.h
> @@ -252,6 +252,7 @@ struct vgic_dist {
>  
>  	struct vgic_vm_ops	vm_ops;
>  	struct vgic_io_device	dist_iodev;
> +	struct vgic_io_device	*redist_iodevs;
>  };
>  
>  struct vgic_v2_cpu_if {
> diff --git a/virt/kvm/arm/vgic-v3-emul.c b/virt/kvm/arm/vgic-v3-emul.c
> index 2f03a36..eb1a797 100644
> --- a/virt/kvm/arm/vgic-v3-emul.c
> +++ b/virt/kvm/arm/vgic-v3-emul.c
> @@ -758,6 +758,9 @@ static int vgic_v3_map_resources(struct kvm *kvm,
>  {
>  	int ret = 0;
>  	struct vgic_dist *dist = &kvm->arch.vgic;
> +	gpa_t rdbase = dist->vgic_redist_base;
> +	struct vgic_io_device *iodevs = NULL;
> +	int i;
>  
>  	if (!irqchip_in_kernel(kvm))
>  		return 0;
> @@ -783,7 +786,41 @@ static int vgic_v3_map_resources(struct kvm *kvm,
>  		goto out;
>  	}
>  
> -	kvm->arch.vgic.ready = true;
> +	ret = vgic_register_kvm_io_dev(kvm, dist->vgic_dist_base,
> +				       GIC_V3_DIST_SIZE, vgic_v3_dist_ranges,
> +				       -1, &dist->dist_iodev);

> +	if (ret)
> +		goto out;
> +
> +	iodevs = kcalloc(dist->nr_cpus, sizeof(iodevs[0]), GFP_KERNEL);
> +	if (!iodevs) {
> +		ret = -ENOMEM;
> +		goto out_unregister;
> +	}
> +
> +	for (i = 0; i < dist->nr_cpus; i++) {
> +		ret = vgic_register_kvm_io_dev(kvm, rdbase,
> +					       SZ_128K, vgic_redist_ranges,
> +					       i, &iodevs[i]);

This looks really weird. You seems to be mapping all redistributors at
the same IPA. Have you actually tested this with an SMP guest?

Or maybe I don't get how this works?

	M.
-- 
Jazz is not dead. It just smells funny.