[Intel-xe] [PATCH] drm/xe/reg_sr: Apply limit to register whitelisting

[Matt Roper]

On Thu, May 25, 2023 at 08:24:06PM -0300, Gustavo Sousa wrote:
> If RING_MAX_NONPRIV_SLOTS denotes the maximum number of whitelisting
> slots, then it makes sense to refuse going above it.
> 
> Signed-off-by: Gustavo Sousa <gustavo.sousa at intel.com>
> ---
>  drivers/gpu/drm/xe/xe_reg_sr.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/gpu/drm/xe/xe_reg_sr.c b/drivers/gpu/drm/xe/xe_reg_sr.c
> index 0312823101ad..b82f704179a0 100644
> --- a/drivers/gpu/drm/xe/xe_reg_sr.c
> +++ b/drivers/gpu/drm/xe/xe_reg_sr.c
> @@ -231,6 +231,13 @@ void xe_reg_sr_apply_whitelist(struct xe_reg_sr *sr, u32 mmio_base,
>  
>  	p = drm_debug_printer(KBUILD_MODNAME);
>  	xa_for_each(&sr->xa, reg, entry) {
> +		if (slot == RING_MAX_NONPRIV_SLOTS) {
> +			drm_err(&xe->drm,

We probably want xe_gt_err() here so that we'll know which GT we hit
this error on.  Also, it wouldn't hurt to pass hwe as a parameter to
this function (instead of mmio_base) and include hwe->name in the error
message here so that we also know which engine ran out of slots.


Matt

> +				"Maximum register whitelist slots (%d) reached, refusing to add more\n",
> +				RING_MAX_NONPRIV_SLOTS);
> +			break;
> +		}
> +
>  		xe_reg_whitelist_print_entry(&p, 0, reg, entry);
>  		xe_mmio_write32(gt, RING_FORCE_TO_NONPRIV(mmio_base, slot),
>  				reg | entry->set_bits);
> -- 
> 2.40.1
> 

-- 
Matt Roper
Graphics Software Engineer
Linux GPU Platform Enablement
Intel Corporation