Re: [RFC PATCH 34/49] ARM: new VGIC: Add CONFIG registers handlers

[Julien Grall <julien.grall@arm.com>]

Hi Andre,

On 09/02/18 14:39, Andre Przywara wrote:
> The config register handlers are shared between the v2 and v3 emulation,
> so their implementation goes into vgic-mmio.c, to be easily referenced
> from the v3 emulation as well later.
> 
> This is based on Linux commit 79717e4ac09c, written by Andre Przywara.
> 
> Signed-off-by: Andre Przywara <andre.przywara@linaro.org>
> ---
>   xen/arch/arm/vgic/vgic-mmio-v2.c |  2 +-
>   xen/arch/arm/vgic/vgic-mmio.c    | 54 ++++++++++++++++++++++++++++++++++++++++
>   xen/arch/arm/vgic/vgic-mmio.h    |  7 ++++++
>   3 files changed, 62 insertions(+), 1 deletion(-)
> 
> diff --git a/xen/arch/arm/vgic/vgic-mmio-v2.c b/xen/arch/arm/vgic/vgic-mmio-v2.c
> index 0574ff9b16..c0b88b347e 100644
> --- a/xen/arch/arm/vgic/vgic-mmio-v2.c
> +++ b/xen/arch/arm/vgic/vgic-mmio-v2.c
> @@ -98,7 +98,7 @@ static const struct vgic_register_region vgic_v2_dist_registers[] = {
>           vgic_mmio_read_raz, vgic_mmio_write_wi, NULL, NULL, 8,
>           VGIC_ACCESS_32bit | VGIC_ACCESS_8bit),
>       REGISTER_DESC_WITH_BITS_PER_IRQ(GICD_ICFGR,
> -        vgic_mmio_read_raz, vgic_mmio_write_wi, NULL, NULL, 2,
> +        vgic_mmio_read_config, vgic_mmio_write_config, NULL, NULL, 2,
>           VGIC_ACCESS_32bit),
>       REGISTER_DESC_WITH_LENGTH(GICD_SGIR,
>           vgic_mmio_read_raz, vgic_mmio_write_wi, 4,
> diff --git a/xen/arch/arm/vgic/vgic-mmio.c b/xen/arch/arm/vgic/vgic-mmio.c
> index 14570d9d8e..626ce06986 100644
> --- a/xen/arch/arm/vgic/vgic-mmio.c
> +++ b/xen/arch/arm/vgic/vgic-mmio.c
> @@ -356,6 +356,60 @@ void vgic_mmio_write_priority(struct vcpu *vcpu,
>       }
>   }
>   
> +unsigned long vgic_mmio_read_config(struct vcpu *vcpu,
> +                    paddr_t addr, unsigned int len)

Indentation.

> +{
> +    u32 intid = VGIC_ADDR_TO_INTID(addr, 2);

uint32_t

> +    u32 value = 0;

uint32_t.

> +    int i;

unsigned int.

> +
> +    for ( i = 0; i < len * 4; i++ )
> +    {

Same question as priority regarding the atomicity of ICFGR.

> +        struct vgic_irq *irq = vgic_get_irq(vcpu->domain, vcpu, intid + i);
> +
> +        if ( irq->config == VGIC_CONFIG_EDGE )
> +            value |= (2U << (i * 2));
> +
> +        vgic_put_irq(vcpu->domain, irq);
> +    }
> +
> +    return value;
> +}
> +
> +void vgic_mmio_write_config(struct vcpu *vcpu,
> +                paddr_t addr, unsigned int len,
> +                unsigned long val)

Indentation

> +{
> +    u32 intid = VGIC_ADDR_TO_INTID(addr, 2);

uint32_t

> +    int i;

unsigned int

> +    unsigned long flags;
> +
> +    for ( i = 0; i < len * 4; i++ )
> +    {
> +        struct vgic_irq *irq;
> +
> +        /*
> +         * The configuration cannot be changed for SGIs in general,
> +         * for PPIs this is IMPLEMENTATION DEFINED. The arch timer
> +         * code relies on PPIs being level triggered, so we also
> +         * make them read-only here.
> +         */
> +        if ( intid + i < VGIC_NR_PRIVATE_IRQS )
> +            continue;
> +
> +        irq = vgic_get_irq(vcpu->domain, vcpu, intid + i);
> +        spin_lock_irqsave(&irq->irq_lock, flags);
> +
> +        if ( test_bit(i * 2 + 1, &val) )
> +            irq->config = VGIC_CONFIG_EDGE;
> +        else
> +            irq->config = VGIC_CONFIG_LEVEL;
> +
> +        spin_unlock_irqrestore(&irq->irq_lock, flags);
> +        vgic_put_irq(vcpu->domain, irq);
> +    }
> +}
> +
>   static int match_region(const void *key, const void *elt)
>   {
>       const unsigned int offset = (unsigned long)key;
> diff --git a/xen/arch/arm/vgic/vgic-mmio.h b/xen/arch/arm/vgic/vgic-mmio.h
> index 30221096b9..b42ea1bd8a 100644
> --- a/xen/arch/arm/vgic/vgic-mmio.h
> +++ b/xen/arch/arm/vgic/vgic-mmio.h
> @@ -177,6 +177,13 @@ void vgic_mmio_write_priority(struct vcpu *vcpu,
>                     paddr_t addr, unsigned int len,
>                     unsigned long val);
>   
> +unsigned long vgic_mmio_read_config(struct vcpu *vcpu,
> +                    paddr_t addr, unsigned int len);

Indenation here and below.

> +
> +void vgic_mmio_write_config(struct vcpu *vcpu,
> +                paddr_t addr, unsigned int len,
> +                unsigned long val);
> +
>   unsigned int vgic_v2_init_dist_iodev(struct vgic_io_device *dev);
>   
>   /* Find the proper register handler entry given a certain address offset */
> 

Cheers,

-- 
Julien Grall

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