Re: [Intel-gfx] [PATCH v2 2/8] drm/i915/gtt: add xehpsdv_ppgtt_insert_entry

[Ramalingam C <ramalingam.c@intel.com>]

On 2021-12-03 at 17:31:11 +0000, Matthew Auld wrote:
> On 03/12/2021 16:59, Ramalingam C wrote:
> > On 2021-12-03 at 12:24:20 +0000, Matthew Auld wrote:
> > > If this is LMEM then we get a 32 entry PT, with each PTE pointing to
> > > some 64K block of memory, otherwise it's just the usual 512 entry PT.
> > > This very much assumes the caller knows what they are doing.
> > > 
> > > Signed-off-by: Matthew Auld <matthew.auld@intel.com>
> > > Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
> > > Cc: Ramalingam C <ramalingam.c@intel.com>
> > > ---
> > >   drivers/gpu/drm/i915/gt/gen8_ppgtt.c | 50 ++++++++++++++++++++++++++--
> > >   1 file changed, 48 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
> > > index bd3ca0996a23..312b2267bf87 100644
> > > --- a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
> > > +++ b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
> > > @@ -728,13 +728,56 @@ static void gen8_ppgtt_insert_entry(struct i915_address_space *vm,
> > >   		gen8_pdp_for_page_index(vm, idx);
> > >   	struct i915_page_directory *pd =
> > >   		i915_pd_entry(pdp, gen8_pd_index(idx, 2));
> > > +	struct i915_page_table *pt = i915_pt_entry(pd, gen8_pd_index(idx, 1));
> > >   	gen8_pte_t *vaddr;
> > > -	vaddr = px_vaddr(i915_pt_entry(pd, gen8_pd_index(idx, 1)));
> > > +	GEM_BUG_ON(pt->is_compact);
> > 
> > Do we have compact PT for smem with 64k pages?
> 
> It's technically possible but we don't bother trying to support it in the
> driver.
Ok.

Reviewed-by: Ramalingam C <ramalingam.c@intel.com>
> 
> > 
> > > +
> > > +	vaddr = px_vaddr(pt);
> > >   	vaddr[gen8_pd_index(idx, 0)] = gen8_pte_encode(addr, level, flags);
> > >   	clflush_cache_range(&vaddr[gen8_pd_index(idx, 0)], sizeof(*vaddr));
> > >   }
> > > +static void __xehpsdv_ppgtt_insert_entry_lm(struct i915_address_space *vm,
> > > +					    dma_addr_t addr,
> > > +					    u64 offset,
> > > +					    enum i915_cache_level level,
> > > +					    u32 flags)
> > > +{
> > > +	u64 idx = offset >> GEN8_PTE_SHIFT;
> > > +	struct i915_page_directory * const pdp =
> > > +		gen8_pdp_for_page_index(vm, idx);
> > > +	struct i915_page_directory *pd =
> > > +		i915_pd_entry(pdp, gen8_pd_index(idx, 2));
> > > +	struct i915_page_table *pt = i915_pt_entry(pd, gen8_pd_index(idx, 1));
> > > +	gen8_pte_t *vaddr;
> > > +
> > > +	GEM_BUG_ON(!IS_ALIGNED(addr, SZ_64K));
> > > +	GEM_BUG_ON(!IS_ALIGNED(offset, SZ_64K));
> > > +
> > > +	if (!pt->is_compact) {
> > > +		vaddr = px_vaddr(pd);
> > > +		vaddr[gen8_pd_index(idx, 1)] |= GEN12_PDE_64K;
> > > +		pt->is_compact = true;
> > > +	}
> > > +
> > > +	vaddr = px_vaddr(pt);
> > > +	vaddr[gen8_pd_index(idx, 0) / 16] = gen8_pte_encode(addr, level, flags);
> > > +}
> > > +
> > > +static void xehpsdv_ppgtt_insert_entry(struct i915_address_space *vm,
> > > +				       dma_addr_t addr,
> > > +				       u64 offset,
> > > +				       enum i915_cache_level level,
> > > +				       u32 flags)
> > > +{
> > > +	if (flags & PTE_LM)
> > > +		return __xehpsdv_ppgtt_insert_entry_lm(vm, addr, offset,
> > > +						       level, flags);
> > > +
> > > +	return gen8_ppgtt_insert_entry(vm, addr, offset, level, flags);
> > Matt,
> > 
> > Is this call for gen8_*** is for insertion of smem PTE entries on the
> > 64K capable platforms like DG2?
> 
> Yeah, this just falls back to the generic 512 entry layout for the PT.
> 
> > 
> > Ram
> > 
> > > +}
> > > +
> > >   static int gen8_init_scratch(struct i915_address_space *vm)
> > >   {
> > >   	u32 pte_flags;
> > > @@ -937,7 +980,10 @@ struct i915_ppgtt *gen8_ppgtt_create(struct intel_gt *gt,
> > >   	ppgtt->vm.bind_async_flags = I915_VMA_LOCAL_BIND;
> > >   	ppgtt->vm.insert_entries = gen8_ppgtt_insert;
> > > -	ppgtt->vm.insert_page = gen8_ppgtt_insert_entry;
> > > +	if (HAS_64K_PAGES(gt->i915))
> > > +		ppgtt->vm.insert_page = xehpsdv_ppgtt_insert_entry;
> > > +	else
> > > +		ppgtt->vm.insert_page = gen8_ppgtt_insert_entry;
> > >   	ppgtt->vm.allocate_va_range = gen8_ppgtt_alloc;
> > >   	ppgtt->vm.clear_range = gen8_ppgtt_clear;
> > >   	ppgtt->vm.foreach = gen8_ppgtt_foreach;
> > > -- 
> > > 2.31.1
> > >