On 11.03.2022 10:40, Lucas De Marchi wrote: > On Tue, Mar 08, 2022 at 10:17:42PM +0530, Balasubramani Vivekanandan wrote: > > This patch is continuation of the effort to move all pointers in i915, > > which at any point may be pointing to device memory or system memory, to > > iosys_map interface. > > More details about the need of this change is explained in the patch > > series which initiated this task > > https://patchwork.freedesktop.org/series/99711/ > > > > This patch converts all access to the lrc_desc through iosys_map > > interfaces. > > > > Cc: Lucas De Marchi <lucas.demarchi@xxxxxxxxx> > > Cc: John Harrison <John.C.Harrison@xxxxxxxxx> > > Cc: Matthew Brost <matthew.brost@xxxxxxxxx> > > Cc: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@xxxxxxxxx> > > Signed-off-by: Balasubramani Vivekanandan <balasubramani.vivekanandan@xxxxxxxxx> > > --- > > ... > > > diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc.h b/drivers/gpu/drm/i915/gt/uc/intel_guc.h > > @@ -2245,13 +2256,13 @@ static void prepare_context_registration_info(struct intel_context *ce) > > GEM_BUG_ON(i915_gem_object_is_lmem(guc->ct.vma->obj) != > > i915_gem_object_is_lmem(ce->ring->vma->obj)); > > > > - desc = __get_lrc_desc(guc, ctx_id); > > - desc->engine_class = engine_class_to_guc_class(engine->class); > > - desc->engine_submit_mask = engine->logical_mask; > > - desc->hw_context_desc = ce->lrc.lrca; > > - desc->priority = ce->guc_state.prio; > > - desc->context_flags = CONTEXT_REGISTRATION_FLAG_KMD; > > - guc_context_policy_init(engine, desc); > > + memset(&desc, 0, sizeof(desc)); > > previously we would re-use whatever was left in > guc->lrc_desc_pool_vaddr. Here we are changing it to always zero > everything and set the fields we are interested in. > > As I'm not too familiar with this part and I see us traversing child guc_process_desc > which may point to the same id, it doesn't _feel_ safe. Did you check if > this is not zero'ing what it shouldn't? > > Matt Brost / John / Daniele, could you clarify? > > thanks > Lucas De Marchi I verified that struct guc_lrc_desc is not updated anywhere else in the driver other than in prepare_context_registration_info. So I went ahead with clearing it before updating the fields. But I will still wait for comments from Matt Brost/ John / Daniele for their confirmation. Thanks Bala
