Re: [PATCH 10/47] drm/i915/guc: Add lrc descriptor context lookup array

[John Harrison]

On 6/25/2021 10:26, Matthew Brost wrote:
On Fri, Jun 25, 2021 at 03:17:51PM +0200, Michal Wajdeczko wrote:
On 24.06.2021 09:04, Matthew Brost wrote:
Add lrc descriptor context lookup array which can resolve the
intel_context from the lrc descriptor index. In addition to lookup, it
can determine in the lrc descriptor context is currently registered with
the GuC by checking if an entry for a descriptor index is present.
Future patches in the series will make use of this array.
s/lrc/LRC
I guess? lrc and LRC are used interchangeably throughout the current
code base.
It is an abbreviation so LRC is technically the correct version for a 
comment. The fact that other existing comments are incorrect is not a 
valid reason to perpetuate a mistake :). Might as well fix it if you are 
going to repost the patch anyway for any other reason, but I would not 
call it a blocking issue.

Also, 'can determine in the' should be 'can determine if the'. Again, 
not exactly a blocking issue but should be fixed.

Cc: John Harrison <john.c.harri...@intel.com>
Signed-off-by: Matthew Brost <matthew.br...@intel.com>
---
  drivers/gpu/drm/i915/gt/uc/intel_guc.h        |  5 +++
  .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 32 +++++++++++++++++--
  2 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc.h 
b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
index b28fa54214f2..2313d9fc087b 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc.h
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc.h
@@ -6,6 +6,8 @@
  #ifndef _INTEL_GUC_H_
  #define _INTEL_GUC_H_
  
+#include "linux/xarray.h"
#include <linux/xarray.h>

Yep.

+
  #include "intel_uncore.h"
  #include "intel_guc_fw.h"
  #include "intel_guc_fwif.h"
@@ -46,6 +48,9 @@ struct intel_guc {
        struct i915_vma *lrc_desc_pool;
        void *lrc_desc_pool_vaddr;
  
+	/* guc_id to intel_context lookup */
+       struct xarray context_lookup;
+
        /* Control params for fw initialization */
        u32 params[GUC_CTL_MAX_DWORDS];
btw, IIRC there was idea to move most struct definitions to
intel_guc_types.h, is this still a plan ?

I don't ever recall discussing this but we can certainly do this. For
what it is worth we do introduce intel_guc_submission_types.h a bit
later. I'll make a note about intel_guc_types.h though.

Matt
Yeah, my only recollection was about the submission types header. Are 
there sufficient non-submission fields in the GuC structure to warrant a 
general GuC types header?

With the commit message tweaks and #include fix mentioned above, it 
looks good to me.
Reviewed-by: John Harrison <john.c.harri...@intel.com>


  
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
index a366890fb840..23a94a896a0b 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -65,8 +65,6 @@ static inline struct i915_priolist *to_priolist(struct 
rb_node *rb)
        return rb_entry(rb, struct i915_priolist, node);
  }
  
-/* Future patches will use this function */
-__attribute__ ((unused))
  static struct guc_lrc_desc *__get_lrc_desc(struct intel_guc *guc, u32 index)
  {
        struct guc_lrc_desc *base = guc->lrc_desc_pool_vaddr;
@@ -76,6 +74,15 @@ static struct guc_lrc_desc *__get_lrc_desc(struct intel_guc 
*guc, u32 index)
        return &base[index];
  }
  
+static inline struct intel_context *__get_context(struct intel_guc *guc, u32 id)
+{
+       struct intel_context *ce = xa_load(&guc->context_lookup, id);
+
+       GEM_BUG_ON(id >= GUC_MAX_LRC_DESCRIPTORS);
+
+       return ce;
+}
+
  static int guc_lrc_desc_pool_create(struct intel_guc *guc)
  {
        u32 size;
@@ -96,6 +103,25 @@ static void guc_lrc_desc_pool_destroy(struct intel_guc *guc)
        i915_vma_unpin_and_release(&guc->lrc_desc_pool, I915_VMA_RELEASE_MAP);
  }
  
+static inline void reset_lrc_desc(struct intel_guc *guc, u32 id)
+{
+       struct guc_lrc_desc *desc = __get_lrc_desc(guc, id);
+
+       memset(desc, 0, sizeof(*desc));
+       xa_erase_irq(&guc->context_lookup, id);
+}
+
+static inline bool lrc_desc_registered(struct intel_guc *guc, u32 id)
+{
+       return __get_context(guc, id);
+}
+
+static inline void set_lrc_desc_registered(struct intel_guc *guc, u32 id,
+                                          struct intel_context *ce)
+{
+       xa_store_irq(&guc->context_lookup, id, ce, GFP_ATOMIC);
+}
+
  static void guc_add_request(struct intel_guc *guc, struct i915_request *rq)
  {
        /* Leaving stub as this function will be used in future patches */
@@ -400,6 +426,8 @@ int intel_guc_submission_init(struct intel_guc *guc)
         */
        GEM_BUG_ON(!guc->lrc_desc_pool);
  
+	xa_init_flags(&guc->context_lookup, XA_FLAGS_LOCK_IRQ);
+
        return 0;
  }