Re: [PATCH 02/12] drm/i915/bdw: Abstract PDP usage

[Michel Thierry <michel.thierry@xxxxxxxxx>]

On 3/3/2015 12:16 PM, akash goel wrote:
> On Fri, Feb 20, 2015 at 11:15 PM, Michel Thierry
> <michel.thierry@xxxxxxxxx>  wrote:
> > From: Ben Widawsky<benjamin.widawsky@xxxxxxxxx>
> >
> > Up until now, ppgtt->pdp has always been the root of our page tables.
> > Legacy 32b addresses acted like it had 1 PDP with 4 PDPEs.
> >
> > In preparation for 4 level page tables, we need to stop use ppgtt->pdp
> > directly unless we know it's what we want. The future structure will use
> > ppgtt->pml4 for the top level, and the pdp is just one of the entries
> > being pointed to by a pml4e.
> >
> > v2: Updated after dynamic page allocation changes.
> >
> > Signed-off-by: Ben Widawsky<ben@xxxxxxxxxxxx>
> > Signed-off-by: Michel Thierry<michel.thierry@xxxxxxxxx>  (v2)
> > ---
> >   drivers/gpu/drm/i915/i915_gem_gtt.c | 123 ++++++++++++++++++++----------------
> >   1 file changed, 70 insertions(+), 53 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> > index 489f8db..d3ad517 100644
> > --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> > +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> > @@ -560,6 +560,7 @@ static void gen8_ppgtt_clear_range(struct i915_address_space *vm,
> >   {
> >          struct i915_hw_ppgtt *ppgtt =
> >                  container_of(vm, struct i915_hw_ppgtt, base);
> > +       struct i915_page_directory_pointer_entry *pdp = &ppgtt->pdp; /* FIXME: 48b */
> >          gen8_gtt_pte_t *pt_vaddr, scratch_pte;
> >          unsigned pdpe = start >> GEN8_PDPE_SHIFT & GEN8_PDPE_MASK;
> >          unsigned pde = start >> GEN8_PDE_SHIFT & GEN8_PDE_MASK;
> > @@ -575,10 +576,10 @@ static void gen8_ppgtt_clear_range(struct i915_address_space *vm,
> >                  struct i915_page_table_entry *pt;
> >                  struct page *page_table;
> >
> > -               if (WARN_ON(!ppgtt->pdp.page_directory[pdpe]))
> > +               if (WARN_ON(!pdp->page_directory[pdpe]))
> >                          continue;
> >
> > -               pd = ppgtt->pdp.page_directory[pdpe];
> > +               pd = pdp->page_directory[pdpe];
> >
> >                  if (WARN_ON(!pd->page_tables[pde]))
> >                          continue;
> > @@ -620,6 +621,7 @@ static void gen8_ppgtt_insert_entries(struct i915_address_space *vm,
> >   {
> >          struct i915_hw_ppgtt *ppgtt =
> >                  container_of(vm, struct i915_hw_ppgtt, base);
> > +       struct i915_page_directory_pointer_entry *pdp = &ppgtt->pdp; /* FIXME: 48b */
> >          gen8_gtt_pte_t *pt_vaddr;
> >          unsigned pdpe = start >> GEN8_PDPE_SHIFT & GEN8_PDPE_MASK;
> >          unsigned pde = start >> GEN8_PDE_SHIFT & GEN8_PDE_MASK;
> > @@ -630,7 +632,7 @@ static void gen8_ppgtt_insert_entries(struct i915_address_space *vm,
> >
> >          for_each_sg_page(pages->sgl, &sg_iter, pages->nents, 0) {
> >                  if (pt_vaddr == NULL) {
> > -                       struct i915_page_directory_entry *pd = ppgtt->pdp.page_directory[pdpe];
> > +                       struct i915_page_directory_entry *pd = pdp->page_directory[pdpe];
> >                          struct i915_page_table_entry *pt = pd->page_tables[pde];
> >                          struct page *page_table = pt->page;
> >
> > @@ -708,16 +710,17 @@ static void gen8_free_page_tables(struct i915_page_directory_entry *pd, struct d
> >   static void gen8_ppgtt_unmap_pages(struct i915_hw_ppgtt *ppgtt)
> >   {
> >          struct pci_dev *hwdev = ppgtt->base.dev->pdev;
> > +       struct i915_page_directory_pointer_entry *pdp = &ppgtt->pdp; /* FIXME: 48b */
> >          int i, j;
> >
> > -       for_each_set_bit(i, ppgtt->pdp.used_pdpes,
> > +       for_each_set_bit(i, pdp->used_pdpes,
> >                          I915_PDPES_PER_PDP(ppgtt->base.dev)) {
> >                  struct i915_page_directory_entry *pd;
> >
> > -               if (WARN_ON(!ppgtt->pdp.page_directory[i]))
> > +               if (WARN_ON(!pdp->page_directory[i]))
> >                          continue;
> >
> > -               pd = ppgtt->pdp.page_directory[i];
> > +               pd = pdp->page_directory[i];
> >                  if (!pd->daddr)
> >                          pci_unmap_page(hwdev, pd->daddr, PAGE_SIZE,
> >                                          PCI_DMA_BIDIRECTIONAL);
> > @@ -743,15 +746,21 @@ static void gen8_ppgtt_free(struct i915_hw_ppgtt *ppgtt)
> >   {
> >          int i;
> >
> > -       for_each_set_bit(i, ppgtt->pdp.used_pdpes,
> > -                               I915_PDPES_PER_PDP(ppgtt->base.dev)) {
> > -               if (WARN_ON(!ppgtt->pdp.page_directory[i]))
> > -                       continue;
> > +       if (!USES_FULL_48BIT_PPGTT(ppgtt->base.dev)) {
> > +               for_each_set_bit(i, ppgtt->pdp.used_pdpes,
> > +                                I915_PDPES_PER_PDP(ppgtt->base.dev)) {
> > +                       if (WARN_ON(!ppgtt->pdp.page_directory[i]))
> > +                               continue;
> >
> > -               gen8_free_page_tables(ppgtt->pdp.page_directory[i], ppgtt->base.dev);
> > -               unmap_and_free_pd(ppgtt->pdp.page_directory[i], ppgtt->base.dev);
> > +                       gen8_free_page_tables(ppgtt->pdp.page_directory[i],
> > +                                             ppgtt->base.dev);
> > +                       unmap_and_free_pd(ppgtt->pdp.page_directory[i],
> > +                                         ppgtt->base.dev);
> > +               }
> > +               unmap_and_free_pdp(&ppgtt->pdp, ppgtt->base.dev);
> > +       } else {
> > +               BUG(); /* to be implemented later */
> >          }
> > -       unmap_and_free_pdp(&ppgtt->pdp, ppgtt->base.dev);
> >   }
> >
> >   static void gen8_ppgtt_cleanup(struct i915_address_space *vm)
> > @@ -765,7 +774,7 @@ static void gen8_ppgtt_cleanup(struct i915_address_space *vm)
> >
> >   /**
> >    * gen8_ppgtt_alloc_pagetabs() - Allocate page tables for VA range.
> > - * @ppgtt:     Master ppgtt structure.
> > + * @vm:                Master vm structure.
> >    * @pd:                Page directory for this address range.
> >    * @start:     Starting virtual address to begin allocations.
> >    * @length     Size of the allocations.
> > @@ -781,12 +790,13 @@ static void gen8_ppgtt_cleanup(struct i915_address_space *vm)
> >    *
> >    * Return: 0 if success; negative error code otherwise.
> >    */
> > -static int gen8_ppgtt_alloc_pagetabs(struct i915_hw_ppgtt *ppgtt,
> > +static int gen8_ppgtt_alloc_pagetabs(struct i915_address_space *vm,
> >                                       struct i915_page_directory_entry *pd,
> >                                       uint64_t start,
> >                                       uint64_t length,
> >                                       unsigned long *new_pts)
> >   {
> > +       struct drm_device *dev = vm->dev;
> >          struct i915_page_table_entry *pt;
> >          uint64_t temp;
> >          uint32_t pde;
> > @@ -799,7 +809,7 @@ static int gen8_ppgtt_alloc_pagetabs(struct i915_hw_ppgtt *ppgtt,
> >                          continue;
> >                  }
> >
> > -               pt = alloc_pt_single(ppgtt->base.dev);
> > +               pt = alloc_pt_single(dev);
> >                  if (IS_ERR(pt))
> >                          goto unwind_out;
> >
> > @@ -811,14 +821,14 @@ static int gen8_ppgtt_alloc_pagetabs(struct i915_hw_ppgtt *ppgtt,
> >
> >   unwind_out:
> >          for_each_set_bit(pde, new_pts, GEN8_PDES_PER_PAGE)
> > -               unmap_and_free_pt(pd->page_tables[pde], ppgtt->base.dev);
> > +               unmap_and_free_pt(pd->page_tables[pde], dev);
> >
> >          return -ENOMEM;
> >   }
> >
> >   /**
> >    * gen8_ppgtt_alloc_page_directories() - Allocate page directories for VA range.
> > - * @ppgtt:     Master ppgtt structure.
> > + * @vm:                Master vm structure.
> >    * @pdp:       Page directory pointer for this address range.
> >    * @start:     Starting virtual address to begin allocations.
> >    * @length     Size of the allocations.
> > @@ -839,16 +849,17 @@ unwind_out:
> >    *
> >    * Return: 0 if success; negative error code otherwise.
> >    */
> > -static int gen8_ppgtt_alloc_page_directories(struct i915_hw_ppgtt *ppgtt,
> > +static int gen8_ppgtt_alloc_page_directories(struct i915_address_space *vm,
> >                                       struct i915_page_directory_pointer_entry *pdp,
> >                                       uint64_t start,
> >                                       uint64_t length,
> >                                       unsigned long *new_pds)
> >   {
> > +       struct drm_device *dev = vm->dev;
> >          struct i915_page_directory_entry *pd;
> >          uint64_t temp;
> >          uint32_t pdpe;
> > -       size_t pdpes =  I915_PDPES_PER_PDP(ppgtt->base.dev);
> > +       size_t pdpes =  I915_PDPES_PER_PDP(vm->dev);
> >
> >          BUG_ON(!bitmap_empty(new_pds, pdpes));
> >
> > @@ -859,7 +870,7 @@ static int gen8_ppgtt_alloc_page_directories(struct i915_hw_ppgtt *ppgtt,
> >                  if (pd)
> >                          continue;
> >
> > -               pd = alloc_pd_single(ppgtt->base.dev);
> > +               pd = alloc_pd_single(dev);
> >                  if (IS_ERR(pd))
> >                          goto unwind_out;
> >
> > @@ -871,7 +882,7 @@ static int gen8_ppgtt_alloc_page_directories(struct i915_hw_ppgtt *ppgtt,
> >
> >   unwind_out:
> >          for_each_set_bit(pdpe, new_pds, pdpes)
> > -               unmap_and_free_pd(pdp->page_directory[pdpe], ppgtt->base.dev);
> > +               unmap_and_free_pd(pdp->page_directory[pdpe], dev);
> >
> >          return -ENOMEM;
> >   }
> > @@ -926,13 +937,13 @@ err_out:
> >          return -ENOMEM;
> >   }
> >
> > -static int gen8_alloc_va_range(struct i915_address_space *vm,
> > -                              uint64_t start,
> > -                              uint64_t length)
> > +static int gen8_alloc_va_range_3lvl(struct i915_address_space *vm,
> > +                                   struct i915_page_directory_pointer_entry *pdp,
> > +                                   uint64_t start,
> > +                                   uint64_t length)
> >   {
> > -       struct i915_hw_ppgtt *ppgtt =
> > -               container_of(vm, struct i915_hw_ppgtt, base);
> >          unsigned long *new_page_dirs, **new_page_tables;
> > +       struct drm_device *dev = vm->dev;
> >          struct i915_page_directory_entry *pd;
> >          const uint64_t orig_start = start;
> >          const uint64_t orig_length = length;
> > @@ -961,17 +972,15 @@ static int gen8_alloc_va_range(struct i915_address_space *vm,
> >                  return ret;
> >
> >          /* Do the allocations first so we can easily bail out */
> > -       ret = gen8_ppgtt_alloc_page_directories(ppgtt, &ppgtt->pdp, start, length,
> > -                                       new_page_dirs);
> > +       ret = gen8_ppgtt_alloc_page_directories(vm, pdp, start, length, new_page_dirs);
> >          if (ret) {
> >                  free_gen8_temp_bitmaps(new_page_dirs, new_page_tables, pdpes);
> >                  return ret;
> >          }
> >
> > -       /* For every page directory referenced, allocate page tables */
> > -       gen8_for_each_pdpe(pd, &ppgtt->pdp, start, length, temp, pdpe) {
> > +       gen8_for_each_pdpe(pd, pdp, start, length, temp, pdpe) {
> >                  bitmap_zero(new_page_tables[pdpe], GEN8_PDES_PER_PAGE);
> > -               ret = gen8_ppgtt_alloc_pagetabs(ppgtt, pd, start, length,
> > +               ret = gen8_ppgtt_alloc_pagetabs(vm, pd, start, length,
> >                                                  new_page_tables[pdpe]);
> >                  if (ret)
> >                          goto err_out;
> > @@ -980,10 +989,7 @@ static int gen8_alloc_va_range(struct i915_address_space *vm,
> >          start = orig_start;
> >          length = orig_length;
> >
> > -       /* Allocations have completed successfully, so set the bitmaps, and do
> > -        * the mappings. */
> > -       gen8_for_each_pdpe(pd, &ppgtt->pdp, start, length, temp, pdpe) {
> > -               gen8_ppgtt_pde_t *const page_directory = kmap_atomic(pd->page);
> > +       gen8_for_each_pdpe(pd, pdp, start, length, temp, pdpe) {
> >                  struct i915_page_table_entry *pt;
> >                  uint64_t pd_len = gen8_clamp_pd(start, length);
> >                  uint64_t pd_start = start;
> > @@ -1005,20 +1011,10 @@ static int gen8_alloc_va_range(struct i915_address_space *vm,
> >
> >                          /* Our pde is now pointing to the pagetable, pt */
> >                          set_bit(pde, pd->used_pdes);
> > -
> > -                       /* Map the PDE to the page table */
> > -                       __gen8_do_map_pt(page_directory + pde, pt, vm->dev);
> > -
> > -                       /* NB: We haven't yet mapped ptes to pages. At this
> > -                        * point we're still relying on insert_entries() */
> >                  }
> >
> > -               if (!HAS_LLC(vm->dev))
> > -                       drm_clflush_virt_range(page_directory, PAGE_SIZE);
> > -
> > -               kunmap_atomic(page_directory);
> > -
> > -               set_bit(pdpe, ppgtt->pdp.used_pdpes);
> > +               set_bit(pdpe, pdp->used_pdpes);
> > +               gen8_map_pagetable_range(pd, start, length, dev);
> >          }
> >
> >          free_gen8_temp_bitmaps(new_page_dirs, new_page_tables, pdpes);
> > @@ -1027,16 +1023,36 @@ static int gen8_alloc_va_range(struct i915_address_space *vm,
> >   err_out:
> >          while (pdpe--) {
> >                  for_each_set_bit(temp, new_page_tables[pdpe], GEN8_PDES_PER_PAGE)
> > -                       unmap_and_free_pt(pd->page_tables[temp], vm->dev);
> > +                       unmap_and_free_pt(pd->page_tables[temp], dev);
> Sorry the review comment may not be completely pertinent to this very patch.
> In the while loop, on the change of 'pdpe' value, the 'pd' is not
> being updated accordingly.
> The above call to 'unmap_and_free_pt(pd->page_table[temp], dev);'
> should be replaced with
>      'unmap_and_free_pt(pdp->page_directory[pdpe]->page_table[temp], dev);'
> This will give the right page directory.
Fixed in the patch that brings this code (drm/i915/bdw: Dynamic page 
table allocations).

> >          }
> >
> >          for_each_set_bit(pdpe, new_page_dirs, pdpes)
> > -               unmap_and_free_pd(ppgtt->pdp.page_directory[pdpe], vm->dev);
> > +               unmap_and_free_pd(pdp->page_directory[pdpe], dev);
> >
> >          free_gen8_temp_bitmaps(new_page_dirs, new_page_tables, pdpes);
> >          return ret;
> >   }
> >
> > +static int __noreturn gen8_alloc_va_range_4lvl(struct i915_address_space *vm,
> > +                                              struct i915_pml4 *pml4,
> > +                                              uint64_t start,
> > +                                              uint64_t length)
> > +{
> > +       BUG(); /* to be implemented later */
> > +}
> > +
> > +static int gen8_alloc_va_range(struct i915_address_space *vm,
> > +                              uint64_t start, uint64_t length)
> > +{
> > +       struct i915_hw_ppgtt *ppgtt =
> > +               container_of(vm, struct i915_hw_ppgtt, base);
> > +
> > +       if (!USES_FULL_48BIT_PPGTT(vm->dev))
> > +               return gen8_alloc_va_range_3lvl(vm, &ppgtt->pdp, start, length);
> > +       else
> > +               return gen8_alloc_va_range_4lvl(vm, &ppgtt->pml4, start, length);
> > +}
> > +
> >   static void gen8_ppgtt_fini_common(struct i915_hw_ppgtt *ppgtt)
> >   {
> >          unmap_and_free_pt(ppgtt->scratch_pd, ppgtt->base.dev);
> > @@ -1079,12 +1095,13 @@ static int gen8_aliasing_ppgtt_init(struct i915_hw_ppgtt *ppgtt)
> >   {
> >          struct drm_device *dev = ppgtt->base.dev;
> >          struct drm_i915_private *dev_priv = dev->dev_private;
> > +       struct i915_page_directory_pointer_entry *pdp = &ppgtt->pdp; /* FIXME: 48b */
> >          struct i915_page_directory_entry *pd;
> >          uint64_t temp, start = 0, size = dev_priv->gtt.base.total;
> >          uint32_t pdpe;
> >          int ret;
> >
> > -       ret = gen8_ppgtt_init_common(ppgtt, dev_priv->gtt.base.total);
> > +       ret = gen8_ppgtt_init_common(ppgtt, size);
> >          if (ret)
> >                  return ret;
> >
> > @@ -1097,8 +1114,8 @@ static int gen8_aliasing_ppgtt_init(struct i915_hw_ppgtt *ppgtt)
> >                  return ret;
> >          }
> >
> > -       gen8_for_each_pdpe(pd, &ppgtt->pdp, start, size, temp, pdpe)
> > -               gen8_map_pagetable_range(pd, start, size, ppgtt->base.dev);
> > +       gen8_for_each_pdpe(pd, pdp, start, size, temp, pdpe)
> > +               gen8_map_pagetable_range(pd, start, size, dev);
> Sorry, again this comment may not be relevant for this patch.
> Is the explicit call to map the page of page tables really needed here ?
> As prior to this, already there is a call to gen8_alloc_va_range,
> which will map the page of page tables into the pdes, for the entire
> virtual range.
Thanks, it was a left over from a previous rebase (before aliasing and 
full ppgtt inits split). As you say it isn't needed.
Fixed in same patch as your prev comment (drm/i915/bdw: Dynamic page 
table allocations).

> >          ppgtt->base.allocate_va_range = NULL;
> >          ppgtt->base.clear_range = gen8_ppgtt_clear_range;
> > --
> > 2.1.1
> >
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
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