Re: [Xen-devel] [PATCH v2] gic-vgic: skip irqs locking in gic_restore_pending_irqs()

[Julien Grall <julien.grall@xxxxxxx>]

Hi,

On 21/12/2018 18:54, Andrii Anisov wrote:
> From: Andrii Anisov <andrii_anisov@xxxxxxxx>
>
> This function is called under IRQs disabled already, so drop additional
> flags save and restore.
>
> Signed-off-by: Andrii Anisov <andrii_anisov@xxxxxxxx>
Reviewed-by: Julien Grall <julien.grall@xxxxxxx>

I will queue this patch for 4.13.

Cheers,

> ---
>
> This is a half of an RFC patch [1] which relies on the already
> existing code.
>
> [1] https://lists.xenproject.org/archives/html/xen-devel/2018-11/msg03293.html
>
>      Changes in v2:
>      Added an ASSERT() to verify the function should be called with interrupts
>      disabled.
>
> ---
>   xen/arch/arm/gic-vgic.c | 7 ++++---
>   1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/xen/arch/arm/gic-vgic.c b/xen/arch/arm/gic-vgic.c
> index 48922f5..f9098c8 100644
> --- a/xen/arch/arm/gic-vgic.c
> +++ b/xen/arch/arm/gic-vgic.c
> @@ -279,11 +279,12 @@ static void gic_restore_pending_irqs(struct vcpu *v)
>       int lr = 0;
>       struct pending_irq *p, *t, *p_r;
>       struct list_head *inflight_r;
> -    unsigned long flags;
>       unsigned int nr_lrs = gic_get_nr_lrs();
>       int lrs = nr_lrs;
>   
> -    spin_lock_irqsave(&v->arch.vgic.lock, flags);
> +    ASSERT(!local_irq_is_enabled());
> +
> +    spin_lock(&v->arch.vgic.lock);
>   
>       if ( list_empty(&v->arch.vgic.lr_pending) )
>           goto out;
> @@ -327,7 +328,7 @@ found:
>       }
>   
>   out:
> -    spin_unlock_irqrestore(&v->arch.vgic.lock, flags);
> +    spin_unlock(&v->arch.vgic.lock);
>   }
>   
>   void gic_clear_pending_irqs(struct vcpu *v)
--
Julien Grall

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