Quoting Abdiel Janulgue (2019-12-11 05:59:07)
> Fault handler to handle missing pages for lmem objects.
>
> v2: Handle ENXIO in fault error, account for offset in region start
> for fake lmem (Matt).
> Add selftest (Chris).
>
> Signed-off-by: Abdiel Janulgue <abdiel.janulgue@xxxxxxxxxxxxxxx>
> Signed-off-by: Matthew Auld <matthew.auld@xxxxxxxxx>
> Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/i915/gem/i915_gem_lmem.c | 44 ++++++++
> drivers/gpu/drm/i915/gem/i915_gem_lmem.h | 6 +
> drivers/gpu/drm/i915/gem/i915_gem_mman.c | 16 ++-
> drivers/gpu/drm/i915/gem/i915_gem_mman.h | 1 +
> .../drm/i915/gem/selftests/i915_gem_mman.c | 105 ++++++++++++++----
> 5 files changed, 147 insertions(+), 25 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..7e6d8d1546e3 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);
> +
> + 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 +88,18 @@ 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;
> +
> + return (mem->io_start + offset) >> PAGE_SHIFT;
> +}
> +
> bool i915_gem_object_is_lmem(struct drm_i915_gem_object *obj)
> {
> return obj->ops == &i915_gem_lmem_obj_ops;
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_lmem.h b/drivers/gpu/drm/i915/gem/i915_gem_lmem.h
> index 7c176b8b7d2f..917ebef1529f 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_lmem.h
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_lmem.h
> @@ -7,6 +7,7 @@
> #define __I915_GEM_LMEM_H
>
> #include <linux/types.h>
> +#include <linux/mman.h>
>
> struct drm_i915_private;
> struct drm_i915_gem_object;
> @@ -22,8 +23,13 @@ void __iomem *
> i915_gem_object_lmem_io_map_page_atomic(struct drm_i915_gem_object *obj,
> unsigned long n);
>
> +unsigned long i915_gem_object_lmem_io_pfn(struct drm_i915_gem_object *obj,
> + unsigned long n);
> +
> bool i915_gem_object_is_lmem(struct drm_i915_gem_object *obj);
>
> +vm_fault_t vm_fault_lmem(struct vm_fault *vmf);
> +
> struct drm_i915_gem_object *
> i915_gem_object_create_lmem(struct drm_i915_private *i915,
> resource_size_t size,
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
> index 879fff8adc48..c67c07905df5 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
> @@ -11,6 +11,7 @@
> #include "gt/intel_gt.h"
> #include "gt/intel_gt_requests.h"
>
> +#include "i915_gem_lmem.h"
> #include "i915_drv.h"
> #include "i915_gem_gtt.h"
> #include "i915_gem_ioctls.h"
> @@ -203,7 +204,7 @@ compute_partial_view(const struct drm_i915_gem_object *obj,
> return view;
> }
>
> -static vm_fault_t i915_error_to_vmf_fault(int err)
> +vm_fault_t i915_error_to_vmf_fault(int err)
> {
> switch (err) {
> default:
> @@ -216,6 +217,7 @@ static vm_fault_t i915_error_to_vmf_fault(int err)
>
> case -ENOSPC: /* shmemfs allocation failure */
> case -ENOMEM: /* our allocation failure */
> + case -ENXIO:
> return VM_FAULT_OOM;
>
> case 0:
> @@ -560,7 +562,8 @@ __assign_mmap_offset(struct drm_file *file,
> }
>
> if (mmap_type != I915_MMAP_TYPE_GTT &&
> - !i915_gem_object_has_struct_page(obj)) {
> + !i915_gem_object_has_struct_page(obj) &&
> + !i915_gem_object_is_lmem(obj)) {
!i915_gem_object_type_has(STRUCT_PAGE | IOMEM)
> err = -ENODEV;
> goto out;
> }
> @@ -694,6 +697,12 @@ static const struct vm_operations_struct vm_ops_cpu = {
> .close = vm_close,
> };
>
> +static const struct vm_operations_struct vm_ops_lmem = {
> + .fault = vm_fault_lmem,
> + .open = vm_open,
> + .close = vm_close,
> +};
> +
> /*
> * This overcomes the limitation in drm_gem_mmap's assignment of a
> * drm_gem_object as the vma->vm_private_data. Since we need to
> @@ -784,6 +793,9 @@ int i915_gem_mmap(struct file *filp, struct vm_area_struct *vma)
> }
> vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
>
> + if (i915_gem_object_is_lmem(mmo->obj))
> + vma->vm_ops = &vm_ops_lmem;
lmem or iomem?
vm_ops = get_vm_cpu_ops(obj);
if (i915_gem_object_type_has(STRUCT_PAGE))
return &vm_ops_cpu;
if (i915_gem_object_type_has(IOMEM))
return &vm_ops_iomem;
GEM_BUG_ON(1);
return NULL;
?
> +
> return 0;
> }
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.h b/drivers/gpu/drm/i915/gem/i915_gem_mman.h
> index 862e01b7cb69..aded4d0564c9 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_mman.h
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.h
> @@ -23,6 +23,7 @@ int i915_gem_mmap(struct file *filp, struct vm_area_struct *vma);
> int i915_gem_dumb_mmap_offset(struct drm_file *file_priv,
> struct drm_device *dev,
> u32 handle, u64 *offset);
> +vm_fault_t i915_error_to_vmf_fault(int err);
>
> void __i915_gem_object_release_mmap_gtt(struct drm_i915_gem_object *obj);
> void i915_gem_object_release_mmap(struct drm_i915_gem_object *obj);
> diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
> index 591435c5f368..d1335a586b7e 100644
> --- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
> +++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_mman.c
> @@ -9,6 +9,8 @@
> #include "gt/intel_engine_pm.h"
> #include "gt/intel_gt.h"
> #include "gt/intel_gt_pm.h"
> +#include "gem/i915_gem_lmem.h"
> +#include "gem/i915_gem_region.h"
> #include "huge_gem_object.h"
> #include "i915_selftest.h"
> #include "selftests/i915_random.h"
> @@ -726,24 +728,23 @@ static int igt_mmap_offset_exhaustion(void *arg)
> }
>
> #define expand32(x) (((x) << 0) | ((x) << 8) | ((x) << 16) | ((x) << 24))
> -static int igt_mmap(void *arg, enum i915_mmap_type type)
> +static int igt_mmap(struct drm_i915_private *i915, struct drm_i915_gem_object *obj,
> + enum i915_mmap_type type)
> {
> - struct drm_i915_private *i915 = arg;
> - struct drm_i915_gem_object *obj;
> struct i915_mmap_offset *mmo;
> struct vm_area_struct *area;
> unsigned long addr;
> void *vaddr;
> int err = 0, i;
>
> - if (!i915_ggtt_has_aperture(&i915->ggtt))
> - return 0;
> -
> - obj = i915_gem_object_create_internal(i915, PAGE_SIZE);
> - if (IS_ERR(obj))
> - return PTR_ERR(obj);
> + if (!i915_ggtt_has_aperture(&i915->ggtt) &&
> + type == I915_MMAP_TYPE_GTT) {
> + err = 0;
> + goto out;
> + }
>
> - vaddr = i915_gem_object_pin_map(obj, I915_MAP_WB);
> + vaddr = i915_gem_object_pin_map(obj, i915_gem_object_is_lmem(obj) ?
> + I915_MAP_WC : I915_MAP_WB);
> if (IS_ERR(vaddr)) {
> err = PTR_ERR(vaddr);
> goto out;
> @@ -827,12 +828,41 @@ static int igt_mmap(void *arg, enum i915_mmap_type type)
>
> static int igt_mmap_gtt(void *arg)
> {
> - return igt_mmap(arg, I915_MMAP_TYPE_GTT);
> + struct drm_i915_private *i915 = arg;
> + struct drm_i915_gem_object *obj =
> + i915_gem_object_create_internal(i915, PAGE_SIZE);
> + if (IS_ERR(obj))
> + return PTR_ERR(obj);
> +
> + return igt_mmap(i915, obj, I915_MMAP_TYPE_GTT);
> }
>
> static int igt_mmap_cpu(void *arg)
> {
> - return igt_mmap(arg, I915_MMAP_TYPE_WC);
> + struct drm_i915_private *i915 = arg;
> + struct drm_i915_gem_object *obj =
> + i915_gem_object_create_internal(i915, PAGE_SIZE);
> + if (IS_ERR(obj))
> + return PTR_ERR(obj);
> +
> + return igt_mmap(i915, obj, I915_MMAP_TYPE_WC);
> +}
> +
> +static int igt_mmap_lmem(void *arg)
> +{
> + struct drm_i915_private *i915 = arg;
> + struct drm_i915_gem_object *obj;
> +
> + if (!HAS_LMEM(i915)) {
> + pr_info("device lacks LMEM support, skipping\n");
> + return 0;
> + }
> +
> + obj = i915_gem_object_create_lmem(i915, PAGE_SIZE, I915_BO_ALLOC_CONTIGUOUS);
> + if (IS_ERR(obj))
> + return PTR_ERR(obj);
> +
> + return igt_mmap(i915, obj, I915_MMAP_TYPE_WC);
Could we not generalise these to iterate over all memory regions?
-Chris
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