[RFC 06/13] KVM: arm64: ITS: Expose ITT_Entry_Size in GITS_TYPER

[Andre Przywara]

Hi Eric,

On 12/01/17 15:56, Eric Auger wrote:
> An ITT_Entry_Size of 2x8Bytes is reported to the guest
> to provision for ITTE state storage.
> 
> Signed-off-by: Eric Auger <eric.auger at redhat.com>
> ---
>  include/linux/irqchip/arm-gic-v3.h | 1 +
>  virt/kvm/arm/vgic/vgic-its.c       | 3 +++
>  2 files changed, 4 insertions(+)
> 
> diff --git a/include/linux/irqchip/arm-gic-v3.h b/include/linux/irqchip/arm-gic-v3.h
> index 170e00a..8cfd81bc 100644
> --- a/include/linux/irqchip/arm-gic-v3.h
> +++ b/include/linux/irqchip/arm-gic-v3.h
> @@ -233,6 +233,7 @@
>  #define GITS_CTLR_QUIESCENT		(1U << 31)
>  
>  #define GITS_TYPER_PLPIS		(1UL << 0)
> +#define GITS_TYPER_ITT_ENTRY_SIZE_SHIFT	4
>  #define GITS_TYPER_IDBITS_SHIFT		8
>  #define GITS_TYPER_DEVBITS_SHIFT	13
>  #define GITS_TYPER_DEVBITS(r)		((((r) >> GITS_TYPER_DEVBITS_SHIFT) & 0x1f) + 1)
> diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
> index e174220..96378b8 100644
> --- a/virt/kvm/arm/vgic/vgic-its.c
> +++ b/virt/kvm/arm/vgic/vgic-its.c
> @@ -33,6 +33,8 @@
>  #include "vgic.h"
>  #include "vgic-mmio.h"
>  
> +#define ITTE_SIZE 16
> +
>  /*
>   * Creates a new (reference to a) struct vgic_irq for a given LPI.
>   * If this LPI is already mapped on another ITS, we increase its refcount
> @@ -399,6 +401,7 @@ static unsigned long vgic_mmio_read_its_typer(struct kvm *kvm,
>  	 */
>  	reg |= 0x0f << GITS_TYPER_DEVBITS_SHIFT;
>  	reg |= 0x0f << GITS_TYPER_IDBITS_SHIFT;
> +	reg |= ITTE_SIZE << GITS_TYPER_ITT_ENTRY_SIZE_SHIFT;

The field is defined as the "... number of bytes per translation table
entry, minus one.". So it should be: (ITTE_SIZE - 1) << ...

Cheers,
Andre.

>  
>  	return extract_bytes(reg, addr & 7, len);
>  }
>