From mboxrd@z Thu Jan  1 00:00:00 1970
From: Julien Grall <julien.grall@linaro.org>
Subject: Re: [PATCH v8 09/13] xen/arm: second irq injection
 while the first irq is still inflight
Date: Fri, 23 May 2014 16:14:35 +0100
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To: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: julien.grall@citrix.com, xen-devel@lists.xensource.com, Ian.Campbell@citrix.com
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On 05/23/2014 03:50 PM, Stefano Stabellini wrote:
> The following change works:
> 
> diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
> index 33141e3..2a8456f 100644
> --- a/xen/arch/arm/domain.c
> +++ b/xen/arch/arm/domain.c
> @@ -644,6 +644,8 @@ int arch_set_info_guest(
>      else
>          set_bit(_VPF_down, &v->pause_flags);
>  
> +    vgic_vcpu_inject_irq(v, v->domain->arch.evtchn_irq);
> +

This is racy, we may not clear the _VPF_down bit in this function
(depending if VGCF_online is set or not).

Hopefully for ARM, libxc is setting this flags by default but it's not
always true.

>      return 0;
>  }
>  
> diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
> index af5cd6c..d597f63 100644
> --- a/xen/arch/arm/domain_build.c
> +++ b/xen/arch/arm/domain_build.c
> @@ -1087,6 +1087,8 @@ int construct_dom0(struct domain *d)
>      }
>  #endif
>  
> +    vgic_vcpu_inject_irq(v, v->domain->arch.evtchn_irq);
> +

I think it needs a comment in code.

Regards,

-- 
Julien Grall