Re: [PATCH v5 3/3] drm/i915/lrc: User PXP contexts requires runalone bit in lrc

["Balasubrawmanian, Vivaik" <vivaik.balasubrawmanian@intel.com>]

On 9/9/2023 3:38 PM, Alan Previn wrote:
> On Meteorlake onwards, HW specs require that all user contexts that
> run on render or compute engines and require PXP must enforce
> run-alone bit in lrc. Add this enforcement for protected contexts.
>
> Signed-off-by: Alan Previn <alan.previn.teres.alexis@intel.com>
> ---
>   drivers/gpu/drm/i915/gt/intel_lrc.c | 23 +++++++++++++++++++++++
>   1 file changed, 23 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
> index 967fe4d77a87..3df32177e49e 100644
> --- a/drivers/gpu/drm/i915/gt/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
> @@ -845,6 +845,27 @@ lrc_setup_indirect_ctx(u32 *regs,
>   		lrc_ring_indirect_offset_default(engine) << 6;
>   }
>   
> +static bool ctx_needs_runalone(const struct intel_context *ce)
> +{
> +	struct i915_gem_context *gem_ctx;
> +	bool ctx_is_protected = false;
> +
> +	/*
> +	 * On MTL and newer platforms, protected contexts require setting
> +	 * the LRC run-alone bit or else the encryption will not happen.
> +	 */
> +	if (GRAPHICS_VER_FULL(ce->engine->i915) >= IP_VER(12, 70) &&
> +	    (ce->engine->class == COMPUTE_CLASS || ce->engine->class == RENDER_CLASS)) {
> +		rcu_read_lock();
> +		gem_ctx = rcu_dereference(ce->gem_context);
> +		if (gem_ctx)
> +			ctx_is_protected = gem_ctx->uses_protected_content;
> +		rcu_read_unlock();
> +	}
> +
> +	return ctx_is_protected;
> +}
> +
>   static void init_common_regs(u32 * const regs,
>   			     const struct intel_context *ce,
>   			     const struct intel_engine_cs *engine,
> @@ -860,6 +881,8 @@ static void init_common_regs(u32 * const regs,
>   	if (GRAPHICS_VER(engine->i915) < 11)
>   		ctl |= _MASKED_BIT_DISABLE(CTX_CTRL_ENGINE_CTX_SAVE_INHIBIT |
>   					   CTX_CTRL_RS_CTX_ENABLE);
> +	if (ctx_needs_runalone(ce))
> +		ctl |= _MASKED_BIT_ENABLE(BIT(7));
>   	regs[CTX_CONTEXT_CONTROL] = ctl;
>   
>   	regs[CTX_TIMESTAMP] = ce->stats.runtime.last;

Can we please get the bit defined in intel_engine_regs.h with a define 
instead of a number identification?

Review completed conditional to the above fix.

Reviewed-by: Balasubrawmanian, Vivaik 
<vivaik.balasubrawmanian@intel.com> 
<mailto:vivaik.balasubrawmanian@intel.com>