[Intel-gfx] [PATCH] drm/i915: Add lmem fault handler
Chris Wilson
chris at chris-wilson.co.uk
Thu Dec 12 11:45:26 UTC 2019
Quoting Abdiel Janulgue (2019-12-12 11:34:38)
> Fault handler to handle missing pages for lmem objects.
>
> v3: Add get_vm_cpu_ops, iterate over all memory regions in the
> lmem selftest, use remap_io_mapping.
>
> 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 | 40 +++++
> drivers/gpu/drm/i915/gem/i915_gem_lmem.h | 6 +
> drivers/gpu/drm/i915/gem/i915_gem_mman.c | 32 +++-
> drivers/gpu/drm/i915/gem/i915_gem_mman.h | 1 +
> .../drm/i915/gem/selftests/i915_gem_mman.c | 137 +++++++++++++++---
> 5 files changed, 188 insertions(+), 28 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..bbe625935005 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_lmem.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_lmem.c
> @@ -6,8 +6,36 @@
> #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_iomem(struct vm_fault *vmf)
I would push this back to being with the vm_ops and making it static,
over choosing a more appropriate name. I think we will prefer having the
fault routines next to each other for making common future changes.
> +{
> + struct vm_area_struct *area = vmf->vma;
> + struct i915_mmap_offset *priv = area->vm_private_data;
> + struct drm_i915_gem_object *obj = priv->obj;
> + struct intel_memory_region *mem = obj->mm.region;
> + unsigned long size = area->vm_end - area->vm_start;
> + bool write = area->vm_flags & VM_WRITE;
> + int 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);
> +
> + ret = remap_io_mapping(area, area->vm_start,
> + i915_gem_object_lmem_io_pfn(obj, 0), size,
> + &mem->iomap);
> +
> + i915_gem_object_unpin_pages(obj);
In terms of behaviour, I think this is correct. The PTE do not persist
past the lifetime of the lmem allocation so we cannot peek at other
user's data.
> +
> + return i915_error_to_vmf_fault(ret);
> +}
> +
> const struct drm_i915_gem_object_ops i915_gem_lmem_obj_ops = {
> .flags = I915_GEM_OBJECT_HAS_IOMEM,
>
> @@ -56,6 +84,18 @@ 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..36a412ace3cf 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_iomem(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..958ca2033379 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_type_has(obj, I915_GEM_OBJECT_HAS_STRUCT_PAGE |
> + I915_GEM_OBJECT_HAS_IOMEM)) {
> err = -ENODEV;
> goto out;
> }
> @@ -694,6 +697,25 @@ static const struct vm_operations_struct vm_ops_cpu = {
> .close = vm_close,
> };
>
> +static const struct vm_operations_struct vm_ops_iomem = {
> + .fault = vm_fault_iomem,
> + .open = vm_open,
> + .close = vm_close,
> +};
> +
> +static const struct vm_operations_struct *
> +get_vm_cpu_ops(struct drm_i915_gem_object *obj)
> +{
> + if (i915_gem_object_type_has(obj, I915_GEM_OBJECT_HAS_STRUCT_PAGE))
> + return &vm_ops_cpu;
> +
> + if (i915_gem_object_type_has(obj, I915_GEM_OBJECT_HAS_IOMEM))
> + return &vm_ops_iomem;
> +
> + GEM_BUG_ON(1);
GEM_BUG_ON("unknown object type");
> + return NULL;
> +}
> +
> /*
> * 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
> @@ -762,18 +784,18 @@ int i915_gem_mmap(struct file *filp, struct vm_area_struct *vma)
> case I915_MMAP_TYPE_WC:
> vma->vm_page_prot =
> pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
> - vma->vm_ops = &vm_ops_cpu;
> + vma->vm_ops = get_vm_cpu_ops(to_intel_bo(obj));
> break;
>
> case I915_MMAP_TYPE_WB:
> vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
> - vma->vm_ops = &vm_ops_cpu;
> + vma->vm_ops = get_vm_cpu_ops(to_intel_bo(obj));
> break;
>
> case I915_MMAP_TYPE_UC:
> vma->vm_page_prot =
> pgprot_noncached(vm_get_page_prot(vma->vm_flags));
> - vma->vm_ops = &vm_ops_cpu;
> + vma->vm_ops = get_vm_cpu_ops(to_intel_bo(obj));
> break;
>
> case I915_MMAP_TYPE_GTT:
> 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..db78ab33e7cb 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 +828,57 @@ 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;
> + int i, err = 0;
> +
> + if (!HAS_LMEM(i915)) {
> + pr_info("device lacks LMEM support, skipping\n");
> + return 0;
> + }
> +
> + for (i = 0; i < ARRAY_SIZE(i915->mm.regions); i++) {
> + struct intel_memory_region *mem = i915->mm.regions[i];
> + struct drm_i915_gem_object *obj;
> +
> + if (!mem || mem->type != INTEL_MEMORY_LOCAL)
> + continue;
> +
> + obj = i915_gem_object_create_region(mem, PAGE_SIZE,
> + I915_BO_ALLOC_CONTIGUOUS);
> + if (IS_ERR(obj)) {
> + err = PTR_ERR(obj);
> + break;
> + }
> +
> + pr_info("%s: memory region %u", __func__, mem->instance);
> + err = igt_mmap(i915, obj, I915_MMAP_TYPE_WC);
> + if (err)
> + break;
> + }
> +
> + return err;
> }
>
> static int check_present_pte(pte_t *pte, unsigned long addr, void *data)
> @@ -887,20 +933,18 @@ 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 +1003,57 @@ 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);
Unless you have an exception signed in triplicate, do resource
allocation and cleanup in the same scope.
In this case I would pass down an allocator for igt_mmap_revoke, or aim
to do everything via the object_create_region interface below.
> +}
> +
> +static int igt_mmap_lmem_revoke(void *arg)
> +{
> + struct drm_i915_private *i915 = arg;
> + int i, err = 0;
> +
> + if (!HAS_LMEM(i915)) {
> + pr_info("device lacks LMEM support, skipping\n");
> + return 0;
> + }
> +
> + for (i = 0; i < ARRAY_SIZE(i915->mm.regions); i++) {
> + struct intel_memory_region *mem = i915->mm.regions[i];
> + struct drm_i915_gem_object *obj;
> +
> + if (!mem || mem->type != INTEL_MEMORY_LOCAL)
> + continue;
> +
> + obj = i915_gem_object_create_region(mem, PAGE_SIZE,
> + I915_BO_ALLOC_CONTIGUOUS);
> + if (IS_ERR(obj)) {
> + err = PTR_ERR(obj);
> + break;
> + }
I was hoping we would have some more information in the memory region
from which we could derive the expected properties and so test smem,
stolen and lmem from the same test.
Oh well, I can always wish.
> +
> + pr_info("%s: memory region %u", __func__, mem->instance);
> + err = igt_mmap_revoke(i915, obj, I915_MMAP_TYPE_WC);
> + if (err)
> + break;
> + }
> +
> + return err;
> }
>
> int i915_gem_mman_live_selftests(struct drm_i915_private *i915)
> @@ -975,8 +1064,10 @@ 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);
> --
> 2.23.0
>
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