Re: [Qemu-devel] [PATCH v4 13/17] hw/intc/arm_gic: Change behavior of IAR writes

["Edgar E. Iglesias" <edgar.iglesias@gmail.com>]

On Fri, May 01, 2015 at 06:50:39PM +0100, Peter Maydell wrote:
> From: Fabian Aggeler <aggelerf@ethz.ch>
> 
> Grouping (GICv2) and Security Extensions change the behavior of IAR
> reads. Acknowledging Group0 interrupts is only allowed from Secure
> state and acknowledging Group1 interrupts from Secure state is only
> allowed if AckCtl bit is set.
> 
> Signed-off-by: Fabian Aggeler <aggelerf@ethz.ch>
> Signed-off-by: Greg Bellows <greg.bellows@linaro.org>
> Message-id: 1429113742-8371-14-git-send-email-greg.bellows@linaro.org
> [PMM: simplify significantly by reusing the existing
>  gic_get_current_pending_irq() rather than reimplementing the
>  same logic here]
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>


> ---
>  hw/intc/arm_gic.c      | 22 ++++++++++++++++------
>  hw/intc/armv7m_nvic.c  |  2 +-
>  hw/intc/gic_internal.h |  2 +-
>  3 files changed, 18 insertions(+), 8 deletions(-)
> 
> diff --git a/hw/intc/arm_gic.c b/hw/intc/arm_gic.c
> index 4ad80e7..6abdb14 100644
> --- a/hw/intc/arm_gic.c
> +++ b/hw/intc/arm_gic.c
> @@ -213,14 +213,24 @@ static void gic_set_running_irq(GICState *s, int cpu, int irq)
>      gic_update(s);
>  }
>  
> -uint32_t gic_acknowledge_irq(GICState *s, int cpu)
> +uint32_t gic_acknowledge_irq(GICState *s, int cpu, MemTxAttrs attrs)
>  {
>      int ret, irq, src;
>      int cm = 1 << cpu;
> -    irq = s->current_pending[cpu];
> -    if (irq == 1023
> -            || GIC_GET_PRIORITY(irq, cpu) >= s->running_priority[cpu]) {
> -        DPRINTF("ACK no pending IRQ\n");
> +
> +    /* gic_get_current_pending_irq() will return 1022 or 1023 appropriately
> +     * for the case where this GIC supports grouping and the pending interrupt
> +     * is in the wrong group.
> +     */
> +    irq = gic_get_current_pending_irq(s, cpu, attrs);;
> +
> +    if (irq >= GIC_MAXIRQ) {
> +        DPRINTF("ACK, no pending interrupt or it is hidden: %d\n", irq);
> +        return irq;
> +    }
> +
> +    if (GIC_GET_PRIORITY(irq, cpu) >= s->running_priority[cpu]) {
> +        DPRINTF("ACK, pending interrupt (%d) has insufficient priority\n", irq);
>          return 1023;
>      }
>      s->last_active[irq][cpu] = s->running_irq[cpu];
> @@ -920,7 +930,7 @@ static MemTxResult gic_cpu_read(GICState *s, int cpu, int offset,
>          }
>          break;
>      case 0x0c: /* Acknowledge */
> -        *data = gic_acknowledge_irq(s, cpu);
> +        *data = gic_acknowledge_irq(s, cpu, attrs);
>          break;
>      case 0x14: /* Running Priority */
>          *data = gic_get_running_priority(s, cpu, attrs);
> diff --git a/hw/intc/armv7m_nvic.c b/hw/intc/armv7m_nvic.c
> index dd06ceb..49368ca 100644
> --- a/hw/intc/armv7m_nvic.c
> +++ b/hw/intc/armv7m_nvic.c
> @@ -122,7 +122,7 @@ int armv7m_nvic_acknowledge_irq(void *opaque)
>      nvic_state *s = (nvic_state *)opaque;
>      uint32_t irq;
>  
> -    irq = gic_acknowledge_irq(&s->gic, 0);
> +    irq = gic_acknowledge_irq(&s->gic, 0, MEMTXATTRS_UNSPECIFIED);
>      if (irq == 1023)
>          hw_error("Interrupt but no vector\n");
>      if (irq >= 32)
> diff --git a/hw/intc/gic_internal.h b/hw/intc/gic_internal.h
> index d3cebef..20c1e8a 100644
> --- a/hw/intc/gic_internal.h
> +++ b/hw/intc/gic_internal.h
> @@ -78,7 +78,7 @@
>  #define REV_NVIC 0xffffffff
>  
>  void gic_set_pending_private(GICState *s, int cpu, int irq);
> -uint32_t gic_acknowledge_irq(GICState *s, int cpu);
> +uint32_t gic_acknowledge_irq(GICState *s, int cpu, MemTxAttrs attrs);
>  void gic_complete_irq(GICState *s, int cpu, int irq, MemTxAttrs attrs);
>  void gic_update(GICState *s);
>  void gic_init_irqs_and_distributor(GICState *s);
> -- 
> 1.9.1
>