Re: [Xen-devel] [PATCH v2 2/9] xen/arm: gic: Do not configure affinity during routing

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Thu, 14 Jul 2016, Julien Grall wrote:
> The affinity of a guest IRQ is set every time the guest enable it (see
> vgic_enable_irqs).
> 
> It is not necessary to set the affinity when the IRQ is routed to the
> guest because Xen will never receive the IRQ until it hass been enabled
> by the guest.
> 
> To keep gic_route_irq_to_{xen,guest} behaving the same way (i.e just
> setting up the routing), the affinity of IRQ routed to Xen is moved into
> __setup_irq.
> 
> Signed-off-by: Julien grall <julien.grall@xxxxxxx>

Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> ---
>     Changes in v2:
>         - Patch renamed
>         - Set the affinity for IRQ routed to Xen in __setup_irq
> ---
>  xen/arch/arm/gic.c        | 11 +++--------
>  xen/arch/arm/irq.c        |  4 ++--
>  xen/include/asm-arm/gic.h |  3 +--
>  3 files changed, 6 insertions(+), 12 deletions(-)
> 
> diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c
> index 5726a05..bc814a0 100644
> --- a/xen/arch/arm/gic.c
> +++ b/xen/arch/arm/gic.c
> @@ -97,24 +97,19 @@ void gic_restore_state(struct vcpu *v)
>  }
>  
>  /*
> - * needs to be called with a valid cpu_mask, ie each cpu in the mask has
> - * already called gic_cpu_init
>   * - desc.lock must be held
>   * - arch.type must be valid (i.e != IRQ_TYPE_INVALID)
>   */
>  static void gic_set_irq_properties(struct irq_desc *desc,
> -                                   const cpumask_t *cpu_mask,
>                                     unsigned int priority)
>  {
>      gic_hw_ops->set_irq_properties(desc, priority);
> -    desc->handler->set_affinity(desc, cpu_mask);
>  }
>  
>  /* Program the GIC to route an interrupt to the host (i.e. Xen)
>   * - needs to be called with desc.lock held
>   */
> -void gic_route_irq_to_xen(struct irq_desc *desc, const cpumask_t *cpu_mask,
> -                          unsigned int priority)
> +void gic_route_irq_to_xen(struct irq_desc *desc, unsigned int priority)
>  {
>      ASSERT(priority <= 0xff);     /* Only 8 bits of priority */
>      ASSERT(desc->irq < gic_number_lines());/* Can't route interrupts that 
> don't exist */
> @@ -123,7 +118,7 @@ void gic_route_irq_to_xen(struct irq_desc *desc, const 
> cpumask_t *cpu_mask,
>  
>      desc->handler = gic_hw_ops->gic_host_irq_type;
>  
> -    gic_set_irq_properties(desc, cpu_mask, priority);
> +    gic_set_irq_properties(desc, priority);
>  }
>  
>  /* Program the GIC to route an interrupt to a guest
> @@ -155,7 +150,7 @@ int gic_route_irq_to_guest(struct domain *d, unsigned int 
> virq,
>      desc->handler = gic_hw_ops->gic_guest_irq_type;
>      set_bit(_IRQ_GUEST, &desc->status);
>  
> -    gic_set_irq_properties(desc, cpumask_of(v_target->processor), priority);
> +    gic_set_irq_properties(desc, priority);
>  
>      p->desc = desc;
>      res = 0;
> diff --git a/xen/arch/arm/irq.c b/xen/arch/arm/irq.c
> index 2f8af72..3fc22f2 100644
> --- a/xen/arch/arm/irq.c
> +++ b/xen/arch/arm/irq.c
> @@ -370,6 +370,7 @@ int setup_irq(unsigned int irq, unsigned int irqflags, 
> struct irqaction *new)
>      /* First time the IRQ is setup */
>      if ( disabled )
>      {
> +        gic_route_irq_to_xen(desc, GIC_PRI_IRQ);
>          /* It's fine to use smp_processor_id() because:
>           * For PPI: irq_desc is banked
>           * For SPI: we don't care for now which CPU will receive the
> @@ -377,8 +378,7 @@ int setup_irq(unsigned int irq, unsigned int irqflags, 
> struct irqaction *new)
>           * TODO: Handle case where SPI is setup on different CPU than
>           * the targeted CPU and the priority.
>           */
> -        gic_route_irq_to_xen(desc, cpumask_of(smp_processor_id()),
> -                             GIC_PRI_IRQ);
> +        irq_set_affinity(desc, cpumask_of(smp_processor_id()));
>          desc->handler->startup(desc);
>      }
>  
> diff --git a/xen/include/asm-arm/gic.h b/xen/include/asm-arm/gic.h
> index 2fc6126..7ba3846 100644
> --- a/xen/include/asm-arm/gic.h
> +++ b/xen/include/asm-arm/gic.h
> @@ -223,8 +223,7 @@ enum gic_version {
>  extern enum gic_version gic_hw_version(void);
>  
>  /* Program the GIC to route an interrupt */
> -extern void gic_route_irq_to_xen(struct irq_desc *desc, const cpumask_t 
> *cpu_mask,
> -                                 unsigned int priority);
> +extern void gic_route_irq_to_xen(struct irq_desc *desc, unsigned int 
> priority);
>  extern int gic_route_irq_to_guest(struct domain *, unsigned int virq,
>                                    struct irq_desc *desc,
>                                    unsigned int priority);
> -- 
> 1.9.1
> 

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