Re: [Xen-devel] [PATCH 06/21] arm: make vgic lock safe for use in interrupt context.

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Thu, 28 Jun 2012, Ian Campbell wrote:
> In particular vgic_vcpu_inject_irq can be called in both interupt and regular
                                                             ^
> context.

ack, typo aside


> Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
> ---
>  xen/arch/arm/gic.c  |    4 ++--
>  xen/arch/arm/vgic.c |   11 ++++++-----
>  2 files changed, 8 insertions(+), 7 deletions(-)
> 
> diff --git a/xen/arch/arm/gic.c b/xen/arch/arm/gic.c
> index 339c327..1e60d3b 100644
> --- a/xen/arch/arm/gic.c
> +++ b/xen/arch/arm/gic.c
> @@ -604,14 +604,14 @@ static void maintenance_interrupt(int irq, void 
> *dev_id, struct cpu_user_regs *r
>          }
>          spin_unlock(&gic.lock);
>  
> -        spin_lock(&current->arch.vgic.lock);
> +        spin_lock_irq(&current->arch.vgic.lock);
>          p = irq_to_pending(current, virq);
>          if ( p->desc != NULL ) {
>              p->desc->status &= ~IRQ_INPROGRESS;
>              GICC[GICC_DIR] = virq;
>          }
>          list_del_init(&p->inflight);
> -        spin_unlock(&current->arch.vgic.lock);
> +        spin_unlock_irq(&current->arch.vgic.lock);
>  
>          i++;
>      }
> diff --git a/xen/arch/arm/vgic.c b/xen/arch/arm/vgic.c
> index af3523f..a217151 100644
> --- a/xen/arch/arm/vgic.c
> +++ b/xen/arch/arm/vgic.c
> @@ -114,8 +114,8 @@ int vcpu_vgic_init(struct vcpu *v)
>      return 0;
>  }
>  
> -#define vgic_lock(v)   spin_lock(&(v)->domain->arch.vgic.lock)
> -#define vgic_unlock(v) spin_unlock(&(v)->domain->arch.vgic.lock)
> +#define vgic_lock(v)   spin_lock_irq(&(v)->domain->arch.vgic.lock)
> +#define vgic_unlock(v) spin_unlock_irq(&(v)->domain->arch.vgic.lock)
>  
>  #define vgic_lock_rank(v, r) spin_lock(&(r)->lock)
>  #define vgic_unlock_rank(v, r) spin_unlock(&(r)->lock)
> @@ -550,6 +550,7 @@ void vgic_vcpu_inject_irq(struct vcpu *v, unsigned int 
> irq, int virtual)
>      uint8_t priority;
>      struct vgic_irq_rank *rank = vgic_irq_rank(v, 8, idx);
>      struct pending_irq *iter, *n = irq_to_pending(v, irq);
> +    unsigned long flags;
>  
>      /* irq still pending */
>      if (!list_empty(&n->inflight))
> @@ -566,18 +567,18 @@ void vgic_vcpu_inject_irq(struct vcpu *v, unsigned int 
> irq, int virtual)
>  
>      gic_set_guest_irq(irq, GICH_LR_PENDING, priority);
>  
> -    spin_lock(&v->arch.vgic.lock);
> +    spin_lock_irqsave(&v->arch.vgic.lock, flags);
>      list_for_each_entry ( iter, &v->arch.vgic.inflight_irqs, inflight )
>      {
>          if ( iter->priority > priority )
>          {
>              list_add_tail(&n->inflight, &iter->inflight);
> -            spin_unlock(&v->arch.vgic.lock);
> +            spin_unlock_irqrestore(&v->arch.vgic.lock, flags);
>              return;
>          }
>      }
>      list_add_tail(&n->inflight, &v->arch.vgic.inflight_irqs);
> -    spin_unlock(&v->arch.vgic.lock);
> +    spin_unlock_irqrestore(&v->arch.vgic.lock, flags);
>      /* we have a new higher priority irq, inject it into the guest */
>  }
>  
> -- 
> 1.7.9.1
> 
> 
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> 

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