Re: [PATCH for-7.2 v4 07/11] ppc/pnv: add PHB4 helpers for user created pnv-phb

From: "Cédric Le Goater" <clg@kaod.org>
To: Daniel Henrique Barboza <danielhb413@gmail.com>, <qemu-devel@nongnu.org>
Cc: <qemu-ppc@nongnu.org>, <fbarrat@linux.ibm.com>
Subject: Re: [PATCH for-7.2 v4 07/11] ppc/pnv: add PHB4 helpers for user created pnv-phb
Date: Thu, 11 Aug 2022 20:44:55 +0200	[thread overview]
Message-ID: <2fe16781-c586-b787-1446-b79b453ed770@kaod.org> (raw)
In-Reply-To: <20220811163950.578927-8-danielhb413@gmail.com>

On 8/11/22 18:39, Daniel Henrique Barboza wrote:
> The PHB4 backend relies on a link with the corresponding PEC element.
> This is trivial to do during machine_init() time for default devices,
> but not so much for user created ones.
> 
> pnv_phb4_get_pec() is a small variation of the function that was
> reverted by commit 9c10d86fee "ppc/pnv: Remove user-created PHB{3,4,5}
> devices". We'll use it to determine the appropriate PEC for a given user
> created pnv-phb that uses a PHB4 backend.
> 
> This is done during realize() time, in pnv_phb_user_device_init().
> 
> Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>

Reviewed-by: Cédric Le Goater <clg@kaod.org>

Thanks,

C.


> ---
>   hw/ppc/pnv.c | 35 ++++++++++++++++++++++++++++++++---
>   1 file changed, 32 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/ppc/pnv.c b/hw/ppc/pnv.c
> index e82d6522f0..0644f45a1d 100644
> --- a/hw/ppc/pnv.c
> +++ b/hw/ppc/pnv.c
> @@ -281,6 +281,34 @@ static void pnv_dt_icp(PnvChip *chip, void *fdt, uint32_t pir,
>       g_free(reg);
>   }
>   
> +static PnvPhb4PecState *pnv_phb4_get_pec(PnvChip *chip, PnvPHB4 *phb,
> +                                         Error **errp)
> +{
> +    Pnv9Chip *chip9 = PNV9_CHIP(chip);
> +    int chip_id = phb->chip_id;
> +    int index = phb->phb_id;
> +    int i, j;
> +
> +    for (i = 0; i < chip->num_pecs; i++) {
> +        /*
> +         * For each PEC, check the amount of phbs it supports
> +         * and see if the given phb4 index matches an index.
> +         */
> +        PnvPhb4PecState *pec = &chip9->pecs[i];
> +
> +        for (j = 0; j < pec->num_phbs; j++) {
> +            if (index == pnv_phb4_pec_get_phb_id(pec, j)) {
> +                return pec;
> +            }
> +        }
> +    }
> +    error_setg(errp,
> +               "pnv-phb4 chip-id %d index %d didn't match any existing PEC",
> +               chip_id, index);
> +
> +    return NULL;
> +}
> +
>   /*
>    * Adds a PnvPHB to the chip. Returns the parent obj of the
>    * PHB which varies with each version (phb version 3 is parented
> @@ -302,10 +330,11 @@ Object *pnv_chip_add_phb(PnvChip *chip, PnvPHB *phb, Error **errp)
>           chip8->num_phbs++;
>   
>           return OBJECT(chip);
> -    } else {
> -        /* phb4 support will be added later */
> -        return NULL;
>       }
> +
> +    phb->pec = pnv_phb4_get_pec(chip, PNV_PHB4(phb->backend), errp);
> +
> +    return OBJECT(phb->pec);
>   }
>   
>   static void pnv_chip_power8_dt_populate(PnvChip *chip, void *fdt)