[Intel-gfx] [RFC PATCH 146/162] drm/i915/pm: suspend and restore ppgtt mapping

[Chris Wilson]

Quoting Matthew Auld (2020-11-27 12:07:02)
> From: Prathap Kumar Valsan <prathap.kumar.valsan at intel.com>
> 
> During suspend we will lose all page tables as they are allocated in
> LMEM. In-order to  make sure that the contexts do not access the
> corrupted page table after we restore, we are evicting all vma's that
> are bound to vm's. This includes kernel vm.
> 
> During resume, we are restoring the page tables back to scratch page.
> 
> Signed-off-by: Prathap Kumar Valsan <prathap.kumar.valsan at intel.com>
> Signed-off-by: Venkata Ramana Nayana <venkata.ramana.nayana at intel.com>
> Cc: CQ Tang <cq.tang at intel.com>
> ---
>  drivers/gpu/drm/i915/gt/gen8_ppgtt.c  |  13 ++++
>  drivers/gpu/drm/i915/gt/gen8_ppgtt.h  |   2 +
>  drivers/gpu/drm/i915/gt/intel_ppgtt.c |   4 +
>  drivers/gpu/drm/i915/i915_drv.c       | 102 +++++++++++++++++++++++---
>  4 files changed, 112 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
> index b6fcebeef02a..704cab807e0b 100644
> --- a/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
> +++ b/drivers/gpu/drm/i915/gt/gen8_ppgtt.c
> @@ -775,3 +775,16 @@ struct i915_ppgtt *gen8_ppgtt_create(struct intel_gt *gt)
>         kfree(ppgtt);
>         return ERR_PTR(err);
>  }
> +
> +void gen8_restore_ppgtt_mappings(struct i915_address_space *vm)
> +{
> +       const unsigned int count = gen8_pd_top_count(vm);
> +       int i;
> +
> +       for (i = 1; i <= vm->top; i++)
> +               fill_px(vm->scratch[i], vm->scratch[i - 1]->encode);
> +
> +       fill_page_dma(px_base(i915_vm_to_ppgtt(vm)->pd),
> +                     vm->scratch[vm->top]->encode, count);
> +}
> +
> diff --git a/drivers/gpu/drm/i915/gt/gen8_ppgtt.h b/drivers/gpu/drm/i915/gt/gen8_ppgtt.h
> index 76a08b9c1f5c..3fa4b95aaabd 100644
> --- a/drivers/gpu/drm/i915/gt/gen8_ppgtt.h
> +++ b/drivers/gpu/drm/i915/gt/gen8_ppgtt.h
> @@ -6,8 +6,10 @@
>  #ifndef __GEN8_PPGTT_H__
>  #define __GEN8_PPGTT_H__
>  
> +struct i915_address_space;
>  struct intel_gt;
>  
> +void gen8_restore_ppgtt_mappings(struct i915_address_space *vm);
>  struct i915_ppgtt *gen8_ppgtt_create(struct intel_gt *gt);
>  
>  #endif
> diff --git a/drivers/gpu/drm/i915/gt/intel_ppgtt.c b/drivers/gpu/drm/i915/gt/intel_ppgtt.c
> index 34a02643bb75..9b3eacd12a7e 100644
> --- a/drivers/gpu/drm/i915/gt/intel_ppgtt.c
> +++ b/drivers/gpu/drm/i915/gt/intel_ppgtt.c
> @@ -9,6 +9,8 @@
>  #include "intel_gtt.h"
>  #include "gem/i915_gem_lmem.h"
>  #include "gem/i915_gem_region.h"
> +#include "gem/i915_gem_context.h"
> +#include "gem/i915_gem_region.h"
>  #include "gen6_ppgtt.h"
>  #include "gen8_ppgtt.h"
>  
> @@ -317,3 +319,5 @@ void ppgtt_init(struct i915_ppgtt *ppgtt, struct intel_gt *gt)
>         ppgtt->vm.vma_ops.set_pages   = ppgtt_set_pages;
>         ppgtt->vm.vma_ops.clear_pages = clear_pages;
>  }
> +
> +
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index e8c4931fc818..7115f4db5043 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -64,6 +64,7 @@
>  #include "gem/i915_gem_context.h"
>  #include "gem/i915_gem_ioctls.h"
>  #include "gem/i915_gem_mman.h"
> +#include "gt/gen8_ppgtt.h"
>  #include "gt/intel_gt.h"
>  #include "gt/intel_gt_pm.h"
>  #include "gt/intel_rc6.h"
> @@ -1136,13 +1137,13 @@ static int intel_dmem_evict_buffers(struct drm_device *dev, bool in_suspend)
>  
>                                 mutex_unlock(&mem->objects.lock);
>  
> -                               if (in_suspend)
> -                                       i915_gem_object_unbind(obj, 0);
> -
>                                 if (in_suspend) {
>                                         obj->swapto = NULL;
>                                         obj->evicted = false;
>                                         obj->do_swapping = true;
> +
> +                                       i915_gem_object_unbind(obj, 0);
> +
>                                         ret = __i915_gem_object_put_pages(obj);
>                                         obj->do_swapping = false;
>                                         if (ret) {
> @@ -1176,6 +1177,43 @@ static int intel_dmem_evict_buffers(struct drm_device *dev, bool in_suspend)
>         return ret;
>  }
>  
> +static int i915_gem_suspend_ppgtt_mappings(struct drm_i915_private *i915)
> +{
> +       struct i915_gem_context *ctx, *cn;
> +       int ret;
> +
> +       spin_lock(&i915->gem.contexts.lock);
> +       list_for_each_entry_safe(ctx, cn, &i915->gem.contexts.list, link) {

Wrong list. Bad starting point from GEM.
-Chris