drm/i915/gtt: map the PD up front

We need to generalise our accessor for the page directories and tables from
using the simple kmap_atomic to support local memory, and this setup
must be done on acquisition of the backing storage prior to entering
fence execution contexts. Here we replace the kmap with the object
mapping code that for simple single page shmemfs object will return a
plain kmap, that is then kept for the lifetime of the page directory.

Note that keeping the mapping around is a potential concern here, since
while the vma is pinned the mapping remains there for the PDs
underneath, or at least until the used_count reaches zero, at which
point we can safely destroy the mapping. For 32b this will be even worse
since the address space is more limited, but since this change mostly
impacts full ppGTT platforms, the justification is that for modern
platforms we shouldn't care too much about 32b.

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210427085417.120246-3-matthew.auld@intel.com

1 files changed, 6 insertions, 5 deletions

diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.h b/drivers/gpu/drm/i915/gt/intel_gtt.h
index e67e34e17913..40e486704558 100644
--- a/drivers/gpu/drm/i915/gt/intel_gtt.h
+++ b/drivers/gpu/drm/i915/gt/intel_gtt.h
@@ -180,6 +180,9 @@ struct page *__px_page(struct drm_i915_gem_object *p);
 dma_addr_t __px_dma(struct drm_i915_gem_object *p);
 #define px_dma(px) (__px_dma(px_base(px)))
 
+void *__px_vaddr(struct drm_i915_gem_object *p);
+#define px_vaddr(px) (__px_vaddr(px_base(px)))
+
 #define px_pt(px) \
 	__px_choose_expr(px, struct i915_page_table *, __x, \
 	__px_choose_expr(px, struct i915_page_directory *, &__x->pt, \
@@ -511,8 +514,6 @@ struct i915_ppgtt *i915_ppgtt_create(struct intel_gt *gt);
 void i915_ggtt_suspend(struct i915_ggtt *gtt);
 void i915_ggtt_resume(struct i915_ggtt *ggtt);
 
-#define kmap_atomic_px(px) kmap_atomic(__px_page(px_base(px)))
-
 void
 fill_page_dma(struct drm_i915_gem_object *p, const u64 val, unsigned int count);
 
@@ -530,8 +531,8 @@ struct i915_page_table *alloc_pt(struct i915_address_space *vm);
 struct i915_page_directory *alloc_pd(struct i915_address_space *vm);
 struct i915_page_directory *__alloc_pd(int npde);
 
-int pin_pt_dma(struct i915_address_space *vm, struct drm_i915_gem_object *obj);
-int pin_pt_dma_locked(struct i915_address_space *vm, struct drm_i915_gem_object *obj);
+int map_pt_dma(struct i915_address_space *vm, struct drm_i915_gem_object *obj);
+int map_pt_dma_locked(struct i915_address_space *vm, struct drm_i915_gem_object *obj);
 
 void free_px(struct i915_address_space *vm,
 	     struct i915_page_table *pt, int lvl);
@@ -578,7 +579,7 @@ void setup_private_pat(struct intel_uncore *uncore);
 int i915_vm_alloc_pt_stash(struct i915_address_space *vm,
 			   struct i915_vm_pt_stash *stash,
 			   u64 size);
-int i915_vm_pin_pt_stash(struct i915_address_space *vm,
+int i915_vm_map_pt_stash(struct i915_address_space *vm,
 			 struct i915_vm_pt_stash *stash);
 void i915_vm_free_pt_stash(struct i915_address_space *vm,
 			   struct i915_vm_pt_stash *stash);