[Intel-gfx] [PATCH v3 3/3] drm/i915/gtt/dg1: add PTE_LM plumbing for GGTT

[Matthew Auld]

On Wed, 3 Feb 2021 at 16:51, Tang, CQ <cq.tang at intel.com> wrote:
>
>
>
> > -----Original Message-----
> > From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf Of
> > Matthew Auld
> > Sent: Wednesday, February 3, 2021 7:24 AM
> > To: intel-gfx at lists.freedesktop.org
> > Cc: Chris Wilson <chris at chris-wilson.co.uk>
> > Subject: [Intel-gfx] [PATCH v3 3/3] drm/i915/gtt/dg1: add PTE_LM plumbing
> > for GGTT
> >
> > For the PTEs we get an LM bit, to signal whether the page resides in SMEM or
> > LMEM.
> >
> > Based on a patch from Michel Thierry.
> >
> > Signed-off-by: Matthew Auld <matthew.auld at intel.com>
> > Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> > Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
> > Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
> > ---
> >  drivers/gpu/drm/i915/gt/intel_ggtt.c | 24 +++++++++++++++++++-----
> > drivers/gpu/drm/i915/gt/intel_gtt.h  |  4 +++-
> >  2 files changed, 22 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/gt/intel_ggtt.c
> > b/drivers/gpu/drm/i915/gt/intel_ggtt.c
> > index fc399ac16eda..b0b8ded834f0 100644
> > --- a/drivers/gpu/drm/i915/gt/intel_ggtt.c
> > +++ b/drivers/gpu/drm/i915/gt/intel_ggtt.c
> > @@ -10,6 +10,8 @@
> >
> >  #include <drm/i915_drm.h>
> >
> > +#include "gem/i915_gem_lmem.h"
> > +
> >  #include "intel_gt.h"
> >  #include "i915_drv.h"
> >  #include "i915_scatterlist.h"
> > @@ -189,7 +191,12 @@ static u64 gen8_ggtt_pte_encode(dma_addr_t addr,
> >                               enum i915_cache_level level,
> >                               u32 flags)
> >  {
> > -     return addr | _PAGE_PRESENT;
> > +     gen8_pte_t pte = addr | _PAGE_PRESENT;
> > +
> > +     if (flags & PTE_LM)
> > +             pte |= GEN12_GGTT_PTE_LM;
> > +
> > +     return pte;
> >  }
> >
> >  static void gen8_set_pte(void __iomem *addr, gen8_pte_t pte) @@ -201,13
> > +208,13 @@ static void gen8_ggtt_insert_page(struct i915_address_space
> > *vm,
> >                                 dma_addr_t addr,
> >                                 u64 offset,
> >                                 enum i915_cache_level level,
> > -                               u32 unused)
> > +                               u32 flags)
> >  {
> >       struct i915_ggtt *ggtt = i915_vm_to_ggtt(vm);
> >       gen8_pte_t __iomem *pte =
> >               (gen8_pte_t __iomem *)ggtt->gsm + offset /
> > I915_GTT_PAGE_SIZE;
> >
> > -     gen8_set_pte(pte, gen8_ggtt_pte_encode(addr, level, 0));
> > +     gen8_set_pte(pte, gen8_ggtt_pte_encode(addr, level, flags));
> >
> >       ggtt->invalidate(ggtt);
> >  }
> > @@ -217,7 +224,7 @@ static void gen8_ggtt_insert_entries(struct
> > i915_address_space *vm,
> >                                    enum i915_cache_level level,
> >                                    u32 flags)
> >  {
> > -     const gen8_pte_t pte_encode = gen8_ggtt_pte_encode(0, level, 0);
> > +     const gen8_pte_t pte_encode = gen8_ggtt_pte_encode(0, level,
> > flags);
> >       struct i915_ggtt *ggtt = i915_vm_to_ggtt(vm);
> >       gen8_pte_t __iomem *gte;
> >       gen8_pte_t __iomem *end;
> > @@ -459,6 +466,8 @@ static void ggtt_bind_vma(struct i915_address_space
> > *vm,
> >       pte_flags = 0;
> >       if (i915_gem_object_is_readonly(obj))
> >               pte_flags |= PTE_READ_ONLY;
> > +     if (i915_gem_object_is_lmem(obj))
> > +             pte_flags |= PTE_LM;
> >
> >       vm->insert_entries(vm, vma, cache_level, pte_flags);
> >       vma->page_sizes.gtt = I915_GTT_PAGE_SIZE; @@ -794,6 +803,7 @@
> > static int ggtt_probe_common(struct i915_ggtt *ggtt, u64 size)
> >       struct drm_i915_private *i915 = ggtt->vm.i915;
> >       struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
> >       phys_addr_t phys_addr;
> > +     u32 pte_flags;
> >       int ret;
> >
> >       /* For Modern GENs the PTEs and register space are split in the BAR
> > */ @@ -823,9 +833,13 @@ static int ggtt_probe_common(struct i915_ggtt
> > *ggtt, u64 size)
> >               return ret;
> >       }
> >
> > +     pte_flags = 0;
> > +     if (i915_gem_object_is_lmem(ggtt->vm.scratch[0]))
> > +             pte_flags |= PTE_LM;
> > +
> >       ggtt->vm.scratch[0]->encode =
> >               ggtt->vm.pte_encode(px_dma(ggtt->vm.scratch[0]),
> > -                                 I915_CACHE_NONE, 0);
> > +                                 I915_CACHE_NONE, pte_flags);
> >
> >       return 0;
> >  }
> > diff --git a/drivers/gpu/drm/i915/gt/intel_gtt.h
> > b/drivers/gpu/drm/i915/gt/intel_gtt.h
> > index 0eef625dd787..24b5808df16d 100644
> > --- a/drivers/gpu/drm/i915/gt/intel_gtt.h
> > +++ b/drivers/gpu/drm/i915/gt/intel_gtt.h
> > @@ -85,7 +85,9 @@ typedef u64 gen8_pte_t;
> >  #define BYT_PTE_SNOOPED_BY_CPU_CACHES        REG_BIT(2)
> >  #define BYT_PTE_WRITEABLE            REG_BIT(1)
> >
> > -#define GEN12_PPGTT_PTE_LM BIT_ULL(11)
> > +#define GEN12_PPGTT_PTE_LM   BIT_ULL(11)
> > +
> > +#define GEN12_GGTT_PTE_LM    BIT_ULL(1)
>
> Where does the Bspec say bit-1 is for LMEM?

Bspec: 45015 <- GGTT
Bspec: 45040 <- ppGTT

I'll update the commit messages.

>
> --CQ
>
> >
> >  /*
> >   * Cacheability Control is a 4-bit value. The low three bits are stored in bits
> > --
> > 2.26.2
> >
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx at lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx