[Intel-gfx] [PATCH] drm/i915: Add lmem fault handler
Chris Wilson
chris at chris-wilson.co.uk
Thu Dec 5 10:31:47 UTC 2019
Quoting Matthew Auld (2019-12-05 10:20:55)
> On Thu, 5 Dec 2019 at 10:14, Abdiel Janulgue
> <abdiel.janulgue at linux.intel.com> wrote:
> >
> > Fault handler to handle missing pages for lmem objects.
> >
> > Signed-off-by: Abdiel Janulgue <abdiel.janulgue at linux.intel.com>
> > Signed-off-by: Matthew Auld <matthew.auld at intel.com>
> > Cc: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> > ---
> > drivers/gpu/drm/i915/gem/i915_gem_lmem.c | 43 ++++++++++++++++++++++++
> > drivers/gpu/drm/i915/gem/i915_gem_lmem.h | 6 ++++
> > drivers/gpu/drm/i915/gem/i915_gem_mman.c | 15 +++++++--
> > drivers/gpu/drm/i915/gem/i915_gem_mman.h | 1 +
> > 4 files changed, 63 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_lmem.c b/drivers/gpu/drm/i915/gem/i915_gem_lmem.c
> > index 0e2bf6b7e143..78ac8d160cd7 100644
> > --- a/drivers/gpu/drm/i915/gem/i915_gem_lmem.c
> > +++ b/drivers/gpu/drm/i915/gem/i915_gem_lmem.c
> > @@ -6,8 +6,40 @@
> > #include "intel_memory_region.h"
> > #include "gem/i915_gem_region.h"
> > #include "gem/i915_gem_lmem.h"
> > +#include "gem/i915_gem_mman.h"
> > #include "i915_drv.h"
> >
> > +vm_fault_t vm_fault_lmem(struct vm_fault *vmf)
> > +{
> > + struct vm_area_struct *area = vmf->vma;
> > + struct i915_mmap_offset *priv = area->vm_private_data;
> > + struct drm_i915_gem_object *obj = priv->obj;
> > + unsigned long size = area->vm_end - area->vm_start;
> > + bool write = area->vm_flags & VM_WRITE;
> > + vm_fault_t vmf_ret;
> > + int i, ret;
> > +
> > + /* Sanity check that we allow writing into this object */
> > + if (i915_gem_object_is_readonly(obj) && write)
> > + return VM_FAULT_SIGBUS;
> > +
> > + ret = i915_gem_object_pin_pages(obj);
> > + if (ret)
> > + return i915_error_to_vmf_fault(ret);
>
> Don't we need to handle -ENXIO in i915_error_to_vmf_fault?
>
> > +
> > + for (i = 0; i < size >> PAGE_SHIFT; i++) {
> > + vmf_ret = vmf_insert_pfn(area,
> > + (unsigned long)area->vm_start + i * PAGE_SIZE,
> > + i915_gem_object_lmem_io_pfn(obj, i));
> > + if (vmf_ret != VM_FAULT_NOPAGE)
> > + break;
> > + }
> > +
> > + i915_gem_object_unpin_pages(obj);
> > +
> > + return vmf_ret;
> > +}
> > +
> > const struct drm_i915_gem_object_ops i915_gem_lmem_obj_ops = {
> > .flags = I915_GEM_OBJECT_HAS_IOMEM,
> >
> > @@ -56,6 +88,17 @@ i915_gem_object_lmem_io_map(struct drm_i915_gem_object *obj,
> > return io_mapping_map_wc(&obj->mm.region->iomap, offset, size);
> > }
> >
> > +unsigned long i915_gem_object_lmem_io_pfn(struct drm_i915_gem_object *obj,
> > + unsigned long n)
> > +{
> > + struct intel_memory_region *mem = obj->mm.region;
> > + resource_size_t offset;
> > +
> > + offset = i915_gem_object_get_dma_address(obj, n);
>
> offset -= mem->region.start; for poor old fake local-memory.
And so one asks for the selftests...
-Chris
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