drm/i915: Add lmem fault handler
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Message ID 20191211055907.8398-1-abdiel.janulgue@linux.intel.com
State New
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Series
  • drm/i915: Add lmem fault handler
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Commit Message

Abdiel Janulgue Dec. 11, 2019, 5:59 a.m. UTC
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@linux.intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
---
 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(-)

Comments

Chris Wilson Dec. 11, 2019, 9:39 a.m. UTC | #1
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@linux.intel.com>
> Signed-off-by: Matthew Auld <matthew.auld@intel.com>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> ---
>  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
Chris Wilson Dec. 11, 2019, 3:29 p.m. UTC | #2
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@linux.intel.com>
> Signed-off-by: Matthew Auld <matthew.auld@intel.com>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> ---
>  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;
> +       }

So why aren't we using remap_io_mapping() ?
-Chris
Dan Carpenter Dec. 13, 2019, 9:49 a.m. UTC | #3
Hi Abdiel,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on drm-intel/for-linux-next]
[also build test WARNING on drm-tip/drm-tip next-20191210]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Abdiel-Janulgue/drm-i915-Add-lmem-fault-handler/20191212-031235
base:   git://anongit.freedesktop.org/drm-intel for-linux-next

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

smatch warnings:
drivers/gpu/drm/i915/gem/i915_gem_lmem.c:40 vm_fault_lmem() error: uninitialized symbol 'vmf_ret'.

# https://github.com/0day-ci/linux/commit/527bcb2414222221b5b3cea4909756095ae07d6a
git remote add linux-review https://github.com/0day-ci/linux
git remote update linux-review
git checkout 527bcb2414222221b5b3cea4909756095ae07d6a
vim +/vmf_ret +40 drivers/gpu/drm/i915/gem/i915_gem_lmem.c

527bcb24142222 Abdiel Janulgue 2019-12-11  12  vm_fault_t vm_fault_lmem(struct vm_fault *vmf)
527bcb24142222 Abdiel Janulgue 2019-12-11  13  {
527bcb24142222 Abdiel Janulgue 2019-12-11  14  	struct vm_area_struct *area = vmf->vma;
527bcb24142222 Abdiel Janulgue 2019-12-11  15  	struct i915_mmap_offset *priv = area->vm_private_data;
527bcb24142222 Abdiel Janulgue 2019-12-11  16  	struct drm_i915_gem_object *obj = priv->obj;
527bcb24142222 Abdiel Janulgue 2019-12-11  17  	unsigned long size = area->vm_end - area->vm_start;
527bcb24142222 Abdiel Janulgue 2019-12-11  18  	bool write = area->vm_flags & VM_WRITE;
527bcb24142222 Abdiel Janulgue 2019-12-11  19  	vm_fault_t vmf_ret;
                                                ^^^^^^^^^^^^^^^^^^^

527bcb24142222 Abdiel Janulgue 2019-12-11  20  	int i, ret;
527bcb24142222 Abdiel Janulgue 2019-12-11  21  
527bcb24142222 Abdiel Janulgue 2019-12-11  22  	/* Sanity check that we allow writing into this object */
527bcb24142222 Abdiel Janulgue 2019-12-11  23  	if (i915_gem_object_is_readonly(obj) && write)
527bcb24142222 Abdiel Janulgue 2019-12-11  24  		return VM_FAULT_SIGBUS;
527bcb24142222 Abdiel Janulgue 2019-12-11  25  
527bcb24142222 Abdiel Janulgue 2019-12-11  26  	ret = i915_gem_object_pin_pages(obj);
527bcb24142222 Abdiel Janulgue 2019-12-11  27  	if (ret)
527bcb24142222 Abdiel Janulgue 2019-12-11  28  		return i915_error_to_vmf_fault(ret);
527bcb24142222 Abdiel Janulgue 2019-12-11  29  
527bcb24142222 Abdiel Janulgue 2019-12-11  30  	for (i = 0; i < size >> PAGE_SHIFT; i++) {

Can size be less than a page?

527bcb24142222 Abdiel Janulgue 2019-12-11  31  		vmf_ret = vmf_insert_pfn(area,
527bcb24142222 Abdiel Janulgue 2019-12-11  32  					 (unsigned long)area->vm_start + i * PAGE_SIZE,
527bcb24142222 Abdiel Janulgue 2019-12-11  33  					 i915_gem_object_lmem_io_pfn(obj, i));
527bcb24142222 Abdiel Janulgue 2019-12-11  34  		if (vmf_ret != VM_FAULT_NOPAGE)
527bcb24142222 Abdiel Janulgue 2019-12-11  35  			break;
527bcb24142222 Abdiel Janulgue 2019-12-11  36  	}
527bcb24142222 Abdiel Janulgue 2019-12-11  37  
527bcb24142222 Abdiel Janulgue 2019-12-11  38  	i915_gem_object_unpin_pages(obj);
527bcb24142222 Abdiel Janulgue 2019-12-11  39  
527bcb24142222 Abdiel Janulgue 2019-12-11 @40  	return vmf_ret;
527bcb24142222 Abdiel Janulgue 2019-12-11  41  }

---
0-DAY kernel test infrastructure                 Open Source Technology Center
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org Intel Corporation

Patch
diff mbox series

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)) {
 		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;
+
 	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);
 }
 
 static int check_present_pte(pte_t *pte, unsigned long addr, void *data)
@@ -887,20 +917,18 @@  static int prefault_range(u64 start, u64 len)
 	return __get_user(c, end - 1);
 }
 
-static int igt_mmap_revoke(void *arg, enum i915_mmap_type type)
+static int igt_mmap_revoke(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;
 	unsigned long addr;
 	int err;
 
-	if (!i915_ggtt_has_aperture(&i915->ggtt))
-		return 0;
-
-	obj = i915_gem_object_create_internal(i915, SZ_4M);
-	if (IS_ERR(obj))
-		return PTR_ERR(obj);
+	if (!i915_ggtt_has_aperture(&i915->ggtt) &&
+	    type == I915_MMAP_TYPE_GTT) {
+		err = 0;
+		goto out;
+	}
 
 	mmo = mmap_offset_attach(obj, type, NULL);
 	if (IS_ERR(mmo)) {
@@ -959,12 +987,41 @@  static int igt_mmap_revoke(void *arg, enum i915_mmap_type type)
 
 static int igt_mmap_gtt_revoke(void *arg)
 {
-	return igt_mmap_revoke(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_revoke(i915, obj, I915_MMAP_TYPE_GTT);
 }
 
 static int igt_mmap_cpu_revoke(void *arg)
 {
-	return igt_mmap_revoke(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_revoke(i915, obj, I915_MMAP_TYPE_WC);
+}
+
+static int igt_mmap_lmem_revoke(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_revoke(i915, obj, I915_MMAP_TYPE_WC);
 }
 
 int i915_gem_mman_live_selftests(struct drm_i915_private *i915)
@@ -975,8 +1032,10 @@  int i915_gem_mman_live_selftests(struct drm_i915_private *i915)
 		SUBTEST(igt_mmap_offset_exhaustion),
 		SUBTEST(igt_mmap_gtt),
 		SUBTEST(igt_mmap_cpu),
+		SUBTEST(igt_mmap_lmem),
 		SUBTEST(igt_mmap_gtt_revoke),
 		SUBTEST(igt_mmap_cpu_revoke),
+		SUBTEST(igt_mmap_lmem_revoke),
 	};
 
 	return i915_subtests(tests, i915);