Re: [PATCH v2 05/15] xen: arm: allow platform code to select dom0 event channel irq

[Julien Grall <julien.grall@linaro.org>]

On 11/22/2013 04:24 PM, Ian Campbell wrote:
> Currently the hardcoded use of GUEST_EVTCHN_PPI is problematic if that is a
> real PPI on the platform.
>
> We really need to be smarter about selecting an unused PPI but in the meantime
> we can at least give the platform code the option of hardcoding a number which
> works for the platform.
>
> Hardcode a suitable PPI on the Xgene platform.
>
> Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
> Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

I have a patch somewhere to find a free PPI, I forget to rework it... 
and it's a bit invasive for 4.4.

Acked-by: Julien Grall <julien.grall@linaro.org>

> ---
>   xen/arch/arm/domain.c                |    7 +++++--
>   xen/arch/arm/platform.c              |    7 +++++++
>   xen/arch/arm/platforms/xgene-storm.c |    1 +
>   xen/include/asm-arm/platform.h       |    5 +++++
>   4 files changed, 18 insertions(+), 2 deletions(-)
>
> diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
> index 2f57d01..52d2403 100644
> --- a/xen/arch/arm/domain.c
> +++ b/xen/arch/arm/domain.c
> @@ -31,6 +31,7 @@
>   #include <asm/processor-ca15.h>
>
>   #include <asm/gic.h>
> +#include <asm/platform.h>
>   #include "vtimer.h"
>   #include "vuart.h"
>
> @@ -526,8 +527,10 @@ int arch_domain_create(struct domain *d, unsigned int domcr_flags)
>       if ( (rc = vcpu_domain_init(d)) != 0 )
>           goto fail;
>
> -    /* XXX dom0 needs more intelligent selection of PPI */
> -    d->arch.evtchn_irq = GUEST_EVTCHN_PPI;
> +    if ( d->domain_id )
> +        d->arch.evtchn_irq = GUEST_EVTCHN_PPI;
> +    else
> +        d->arch.evtchn_irq = platform_dom0_evtchn_ppi();
>
>       /*
>        * Virtual UART is only used by linux early printk and decompress code.
> diff --git a/xen/arch/arm/platform.c b/xen/arch/arm/platform.c
> index 0fbbdc7..a7f9ee4 100644
> --- a/xen/arch/arm/platform.c
> +++ b/xen/arch/arm/platform.c
> @@ -156,6 +156,13 @@ bool_t platform_device_is_blacklisted(const struct dt_device_node *node)
>       return dt_match_node(blacklist, node);
>   }
>
> +unsigned int platform_dom0_evtchn_ppi(void)
> +{
> +    if ( platform && platform->dom0_evtchn_ppi )
> +        return platform->dom0_evtchn_ppi;
> +    return GUEST_EVTCHN_PPI;
> +}
> +
>   /*
>    * Local variables:
>    * mode: C
> diff --git a/xen/arch/arm/platforms/xgene-storm.c b/xen/arch/arm/platforms/xgene-storm.c
> index d185a4a..8658996 100644
> --- a/xen/arch/arm/platforms/xgene-storm.c
> +++ b/xen/arch/arm/platforms/xgene-storm.c
> @@ -40,6 +40,7 @@ static const char const *xgene_storm_dt_compat[] __initdata =
>   PLATFORM_START(xgene_storm, "APM X-GENE STORM")
>       .compatible = xgene_storm_dt_compat,
>       .quirks = xgene_storm_quirks,
> +    .dom0_evtchn_ppi = 24,
>   PLATFORM_END
>
>   /*
> diff --git a/xen/include/asm-arm/platform.h b/xen/include/asm-arm/platform.h
> index c9314e5..5900ee4 100644
> --- a/xen/include/asm-arm/platform.h
> +++ b/xen/include/asm-arm/platform.h
> @@ -37,6 +37,10 @@ struct platform_desc {
>        * List of devices which must not pass-through to a guest
>        */
>       const struct dt_device_match *blacklist_dev;
> +    /*
> +     * The IRQ (PPI) to use to inject event channels to dom0.
> +     */
> +    unsigned int dom0_evtchn_ppi;
>   };
>
>   /*
> @@ -61,6 +65,7 @@ void platform_reset(void);
>   void platform_poweroff(void);
>   bool_t platform_has_quirk(uint32_t quirk);
>   bool_t platform_device_is_blacklisted(const struct dt_device_node *node);
> +unsigned int platform_dom0_evtchn_ppi(void);
>
>   #define PLATFORM_START(_name, _namestr)                         \
>   static const struct platform_desc  __plat_desc_##_name __used   \
>

-- 
Julien Grall