Re: [v5 16/19] KVM: Add an arch specific hooks in 'struct kvm_kernel_irqfd'

[Eric Auger <eric.auger@linaro.org>]

On 07/13/2015 11:47 AM, Feng Wu wrote:
> This patch adds an arch specific hooks 'arch_update' in
> 'struct kvm_kernel_irqfd'. On Intel side, it is used to
> update the IRTE when VT-d posted-interrupts is used.
> 
> Signed-off-by: Feng Wu <feng.wu@intel.com>
> ---
>  arch/x86/kvm/x86.c        |  5 +++++
>  include/linux/kvm_host.h  |  3 +++
>  include/linux/kvm_irqfd.h |  2 ++
>  virt/kvm/eventfd.c        | 13 ++++++++++++-
>  4 files changed, 22 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 62bbafe..a88e659 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -8063,6 +8063,11 @@ void kvm_arch_irq_consumer_init(struct irq_bypass_consumer *cons)
>  	cons->del_producer = kvm_arch_irq_bypass_del_producer;
>  }
>  
> +void kvm_arch_irqfd_init(struct kvm_kernel_irqfd *irqfd)
> +{
> +	irqfd->arch_update = kvm_arch_update_pi_irte;
> +}
> +
>  EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_exit);
>  EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_inj_virq);
>  EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_page_fault);
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index e693b3a..b37ebca 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -33,6 +33,8 @@
>  
>  #include <asm/kvm_host.h>
>  
> +struct kvm_kernel_irqfd;
> +
>  /*
>   * The bit 16 ~ bit 31 of kvm_memory_region::flags are internally used
>   * in kvm, other bits are visible for userspace which are defined in
> @@ -1074,6 +1076,7 @@ extern struct kvm_device_ops kvm_arm_vgic_v2_ops;
>  extern struct kvm_device_ops kvm_arm_vgic_v3_ops;
>  
>  void kvm_arch_irq_consumer_init(struct irq_bypass_consumer *cons);
> +void kvm_arch_irqfd_init(struct kvm_kernel_irqfd *irqfd);
need to handle the case this is not implemented by the arch?


>  
>  #ifdef CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT
>  
> diff --git a/include/linux/kvm_irqfd.h b/include/linux/kvm_irqfd.h
> index cf9aad4..47a2696 100644
> --- a/include/linux/kvm_irqfd.h
> +++ b/include/linux/kvm_irqfd.h
> @@ -67,6 +67,8 @@ struct kvm_kernel_irqfd {
>  	struct work_struct shutdown;
>  	struct irq_bypass_consumer consumer;
>  	struct irq_bypass_producer *producer;
> +	int (*arch_update)(struct kvm *kvm, unsigned int host_irq,
> +			   uint32_t guest_irq, bool set);
you must document this cb cannot sleep I think
Eric
>  };
>  
>  #endif /* __LINUX_KVM_IRQFD_H */
> diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
> index 4225eea..762282c 100644
> --- a/virt/kvm/eventfd.c
> +++ b/virt/kvm/eventfd.c
> @@ -276,6 +276,7 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
>  	INIT_LIST_HEAD(&irqfd->list);
>  	INIT_WORK(&irqfd->inject, irqfd_inject);
>  	INIT_WORK(&irqfd->shutdown, irqfd_shutdown);
> +	kvm_arch_irqfd_init(irqfd);
>  	seqcount_init(&irqfd->irq_entry_sc);
>  
>  	f = fdget(args->fd);
> @@ -562,13 +563,23 @@ kvm_irqfd_release(struct kvm *kvm)
>   */
>  void kvm_irq_routing_update(struct kvm *kvm)
>  {
> +	int ret;
>  	struct kvm_kernel_irqfd *irqfd;
>  
>  	spin_lock_irq(&kvm->irqfds.lock);
>  
> -	list_for_each_entry(irqfd, &kvm->irqfds.items, list)
> +	list_for_each_entry(irqfd, &kvm->irqfds.items, list) {
>  		irqfd_update(kvm, irqfd);
>  
> +		if (irqfd->arch_update) {
> +			BUG_ON(!irqfd->producer);
> +			ret = irqfd->arch_update(
> +					irqfd->kvm, irqfd->producer->irq,
> +					irqfd->gsi, 1);
> +			WARN_ON(ret);
> +		}
> +	}
> +
>  	spin_unlock_irq(&kvm->irqfds.lock);
>  }
>  
>