[Intel-gfx] [PATCH] drm/i915: Add lmem fault handler

* [Intel-gfx] [PATCH] drm/i915: Add lmem fault handler
@ 2019-12-11  5:59 Abdiel Janulgue
  2019-12-11  7:40 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for drm/i915: Add lmem fault handler (rev2) Patchwork
                   ` (4 more replies)
  0 siblings, 5 replies; 8+ messages in thread
From: Abdiel Janulgue @ 2019-12-11  5:59 UTC (permalink / raw)
  To: intel-gfx; +Cc: Matthew Auld

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)) {
 		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);
-- 
2.23.0

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