Re: [PATCH v4 14/25] ppc/xive: Introduce helpers for the NVT id

[David Gibson]

On Wed, Sep 18, 2019 at 06:06:34PM +0200, Cédric Le Goater wrote:
> The NVT space is 19 bits wide, giving a maximum of 512K per chip. When
> dispatched on a HW thread, the NVT identifier of a vCPU is pushed/stored
> in the CAM line (word2) of the thread interrupt context.

Ok, that's interesting, but how does it lead to this patch?  Connect
the dots, please.

> 
> Signed-off-by: Cédric Le Goater <address@hidden>
> ---
>  include/hw/ppc/xive.h      |  5 -----
>  include/hw/ppc/xive_regs.h | 21 +++++++++++++++++++++
>  2 files changed, 21 insertions(+), 5 deletions(-)
> 
> diff --git a/include/hw/ppc/xive.h b/include/hw/ppc/xive.h
> index a461753f5da5..794dfcaae0f8 100644
> --- a/include/hw/ppc/xive.h
> +++ b/include/hw/ppc/xive.h
> @@ -469,11 +469,6 @@ void xive_tctx_pic_print_info(XiveTCTX *tctx, Monitor 
> *mon);
>  Object *xive_tctx_create(Object *cpu, XiveRouter *xrtr, Error **errp);
>  void xive_tctx_ipb_update(XiveTCTX *tctx, uint8_t ring, uint8_t ipb);
>  
> -static inline uint32_t xive_nvt_cam_line(uint8_t nvt_blk, uint32_t nvt_idx)
> -{
> -    return (nvt_blk << 19) | nvt_idx;
> -}
> -
>  /*
>   * KVM XIVE device helpers
>   */
> diff --git a/include/hw/ppc/xive_regs.h b/include/hw/ppc/xive_regs.h
> index 08c8bf7172e2..3d7b6fd09664 100644
> --- a/include/hw/ppc/xive_regs.h
> +++ b/include/hw/ppc/xive_regs.h
> @@ -251,4 +251,25 @@ typedef struct XiveNVT {
>  
>  #define xive_nvt_is_valid(nvt)    (be32_to_cpu((nvt)->w0) & NVT_W0_VALID)
>  
> +/*
> + * The VP number space in a block is defined by the END_W6_NVT_INDEX
> + * field of the XIVE END
> + */
> +#define XIVE_NVT_SHIFT                19
> +
> +static inline uint32_t xive_nvt_cam_line(uint8_t nvt_blk, uint32_t nvt_idx)
> +{
> +    return (nvt_blk << XIVE_NVT_SHIFT) | nvt_idx;
> +}
> +
> +static inline uint32_t xive_nvt_idx(uint32_t cam_line)
> +{
> +    return cam_line & ((1 << XIVE_NVT_SHIFT) - 1);
> +}
> +
> +static inline uint32_t xive_nvt_blk(uint32_t cam_line)
> +{
> +    return (cam_line >> XIVE_NVT_SHIFT) & 0xf;
> +}
> +
>  #endif /* PPC_XIVE_REGS_H */

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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