Re: [PATCH v3 49/55] KVM: arm/arm64: vgic-new: vgic_init: implement vgic_create

[Christoffer Dall <christoffer.dall@linaro.org>]

On Fri, May 06, 2016 at 11:46:02AM +0100, Andre Przywara wrote:
> From: Eric Auger <eric.auger@linaro.org>
> 
> This patch implements the vgic_creation function which is
> called on CREATE_IRQCHIP VM IOCTL (v2 only) or KVM_CREATE_DEVICE
> 
> Signed-off-by: Eric Auger <eric.auger@linaro.org>
> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> ---
>  include/kvm/vgic/vgic.h       |  1 +
>  virt/kvm/arm/vgic/vgic-init.c | 84 +++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 85 insertions(+)
> 
> diff --git a/include/kvm/vgic/vgic.h b/include/kvm/vgic/vgic.h
> index d144e3d..899b7b7 100644
> --- a/include/kvm/vgic/vgic.h
> +++ b/include/kvm/vgic/vgic.h
> @@ -202,6 +202,7 @@ struct vgic_cpu {
>  };
>  
>  int kvm_vgic_addr(struct kvm *kvm, unsigned long type, u64 *addr, bool write);
> +int kvm_vgic_create(struct kvm *kvm, u32 type);
>  int kvm_vgic_hyp_init(void);
>  
>  int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid,
> diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c
> index f10997b..a150363 100644
> --- a/virt/kvm/arm/vgic/vgic-init.c
> +++ b/virt/kvm/arm/vgic/vgic-init.c
> @@ -24,6 +24,90 @@
>  #include <asm/kvm_mmu.h>
>  #include "vgic.h"
>  
> +/* CREATION */
> +
> +/**
> + * kvm_vgic_create: triggered by the instantiation of the VGIC device by
> + * user space, either through the legacy ARM specific VM IOCTL (CREATE_IRQCHIP)

nit: is KVM_CREATE_IRQCHIP ARM specific or are we talking about the ARM
implementation of a generic ioctl?

> + * or through the generic VM IOCTL, KVM_CREATE_DEVICE API.
> + * Completion can be tested by irqchip_in_kernel

s/Completion can be tested by irqchip_in_kernel/
  irqchip_in_kernel() tells you if this function succeeded or not/

> + */
> +int kvm_vgic_create(struct kvm *kvm, u32 type)
> +{
> +	int i, vcpu_lock_idx = -1, ret;
> +	struct kvm_vcpu *vcpu;
> +
> +	mutex_lock(&kvm->lock);
> +
> +	if (irqchip_in_kernel(kvm)) {
> +		ret = -EEXIST;
> +		goto out;
> +	}
> +
> +	/*
> +	 * This function is also called by the KVM_CREATE_IRQCHIP handler,
> +	 * which had no chance yet to check the availability of the GICv2
> +	 * emulation. So check this here again. KVM_CREATE_DEVICE does
> +	 * the proper checks already.
> +	 */
> +	if (type == KVM_DEV_TYPE_ARM_VGIC_V2 &&
> +		!kvm_vgic_global_state.can_emulate_gicv2) {
> +		ret = -ENODEV;
> +		goto out;
> +	}
> +
> +	/*
> +	 * Any time a vcpu is run, vcpu_load is called which tries to grab the
> +	 * vcpu->mutex.  By grabbing the vcpu->mutex of all VCPUs we ensure
> +	 * that no other VCPUs are run while we create the vgic.
> +	 */
> +	ret = -EBUSY;
> +	kvm_for_each_vcpu(i, vcpu, kvm) {
> +		if (!mutex_trylock(&vcpu->mutex))
> +			goto out_unlock;
> +		vcpu_lock_idx = i;
> +	}
> +
> +	kvm_for_each_vcpu(i, vcpu, kvm) {
> +		if (vcpu->arch.has_run_once)
> +			goto out_unlock;
> +	}
> +	ret = 0;
> +
> +	if (type == KVM_DEV_TYPE_ARM_VGIC_V2)
> +		kvm->arch.max_vcpus = VGIC_V2_MAX_CPUS;
> +	else
> +		kvm->arch.max_vcpus = VGIC_V3_MAX_CPUS;
> +
> +	if (atomic_read(&kvm->online_vcpus) > kvm->arch.max_vcpus) {
> +		ret = -E2BIG;
> +		goto out_unlock;
> +	}
> +
> +	kvm->arch.vgic.in_kernel = true;
> +	kvm->arch.vgic.vgic_model = type;
> +
> +	/*
> +	 * kvm_vgic_global_state.vctrl_base is set on vgic probe (kvm_arch_init)
> +	 * it is stored in distributor struct for asm save/restore purpose

we don't have any assembly code anymore, so could we simply export the
global state to __hyp code?

> +	 */
> +	kvm->arch.vgic.vctrl_base = kvm_vgic_global_state.vctrl_base;
> +
> +	kvm->arch.vgic.vgic_dist_base = VGIC_ADDR_UNDEF;
> +	kvm->arch.vgic.vgic_cpu_base = VGIC_ADDR_UNDEF;
> +	kvm->arch.vgic.vgic_redist_base = VGIC_ADDR_UNDEF;
> +
> +out_unlock:
> +	for (; vcpu_lock_idx >= 0; vcpu_lock_idx--) {
> +		vcpu = kvm_get_vcpu(kvm, vcpu_lock_idx);
> +		mutex_unlock(&vcpu->mutex);
> +	}
> +
> +out:
> +	mutex_unlock(&kvm->lock);
> +	return ret;
> +}
> +
>  /* GENERIC PROBE */
>  
>  static void vgic_init_maintenance_interrupt(void *info)
> -- 
> 2.7.3
>