[PATCH v3 32/37] drm/i915: Add cpu and lmem fault handlers

Matthew Auld
2019-08-09T22:26:38Z

From: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>

Fault handler to handle missing pages to be filled depending on an
object's backing storage. Handle also changes needed to refault pages
depending on fault handler usage.

Signed-off-by: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
---
drivers/gpu/drm/i915/gem/i915_gem_lmem.c | 54 +++++++
drivers/gpu/drm/i915/gem/i915_gem_lmem.h | 3 +
drivers/gpu/drm/i915/gem/i915_gem_mman.c | 155 +++++++++++++++++++--
drivers/gpu/drm/i915/gem/i915_gem_object.h | 2 +-
drivers/gpu/drm/i915/i915_gem.c | 2 +-
5 files changed, 201 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_lmem.c b/drivers/gpu/drm/i915/gem/i915_gem_lmem.c
index 8d0251af5dfc..2194e2c3bdcd 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_lmem.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_lmem.c
@@ -6,6 +6,7 @@
#include "intel_memory_region.h"
#include "gem/i915_gem_region.h"
#include "gem/i915_gem_lmem.h"
+#include "gt/intel_gt.h"
#include "i915_drv.h"

static int lmem_pread(struct drm_i915_gem_object *obj,
@@ -179,6 +180,59 @@ static int lmem_pwrite(struct drm_i915_gem_object *obj,
return ret;
}

+vm_fault_t i915_gem_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;
+ struct drm_device *dev = obj->base.dev;
+ struct drm_i915_private *i915 = to_i915(dev);
+ 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)
+ goto err;
+
+ 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_offset(obj, i) >> PAGE_SHIFT);
+ if (vmf_ret & VM_FAULT_ERROR) {
+ ret = vm_fault_to_errno(vmf_ret, 0);
+ goto err;
+ }
+ }
+
+ i915_gem_object_unpin_pages(obj);
+err:
+ switch (ret) {
+ case -EIO:
+ if (!intel_gt_is_wedged(&i915->gt))
+ return VM_FAULT_SIGBUS;
+ /* fallthrough */
+ case -EAGAIN:
+ case 0:
+ case -ERESTARTSYS:
+ case -EINTR:
+ case -EBUSY:
+ return VM_FAULT_NOPAGE;
+ case -ENOMEM:
+ return VM_FAULT_OOM;
+ case -ENOSPC:
+ case -EFAULT:
+ return VM_FAULT_SIGBUS;
+ default:
+ WARN_ONCE(ret, "unhandled error in %s: %i\n", __func__, ret);
+ return VM_FAULT_SIGBUS;
+ }
+}

const struct drm_i915_gem_object_ops i915_gem_lmem_obj_ops = {
.flags = I915_GEM_OBJECT_IS_MAPPABLE,
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_lmem.h b/drivers/gpu/drm/i915/gem/i915_gem_lmem.h
index 43e6e715eeed..c3255eb6daa5 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;
@@ -24,6 +25,8 @@ i915_gem_object_lmem_io_map_page_atomic(struct drm_i915_gem_object *obj,
resource_size_t i915_gem_object_lmem_io_offset(struct drm_i915_gem_object *obj,
unsigned long n);

+vm_fault_t i915_gem_fault_lmem(struct vm_fault *vmf);
+
bool i915_gem_object_is_lmem(struct drm_i915_gem_object *obj);

struct drm_i915_gem_object *
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
index a62657a1f011..304ea578fd30 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
@@ -5,6 +5,7 @@
*/

#include <linux/mman.h>
+#include <linux/pfn_t.h>
#include <linux/sizes.h>

#include "gt/intel_gt.h"
@@ -12,6 +13,7 @@
#include "i915_drv.h"
#include "i915_gem_gtt.h"
#include "i915_gem_ioctls.h"
+#include "i915_gem_lmem.h"
#include "i915_gem_object.h"
#include "i915_trace.h"
#include "i915_vma.h"
@@ -371,7 +373,62 @@ vm_fault_t i915_gem_fault(struct vm_fault *vmf)
}
}

-void __i915_gem_object_release_mmap(struct drm_i915_gem_object *obj)
+static vm_fault_t i915_gem_fault_cpu(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;
+ struct drm_device *dev = obj->base.dev;
+ struct drm_i915_private *dev_priv = to_i915(dev);
+ vm_fault_t vmf_ret;
+ unsigned long size = area->vm_end - area->vm_start;
+ bool write = area->vm_flags & VM_WRITE;
+ 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)
+ goto err;
+
+ for (i = 0; i < size >> PAGE_SHIFT; i++) {
+ struct page *page = i915_gem_object_get_page(obj, i);
+ vmf_ret = vmf_insert_pfn(area,
+ (unsigned long)area->vm_start + i * PAGE_SIZE,
+ page_to_pfn(page));
+ if (vmf_ret & VM_FAULT_ERROR) {
+ ret = vm_fault_to_errno(vmf_ret, 0);
+ break;
+ }
+ }
+
+ i915_gem_object_unpin_pages(obj);
+err:
+ switch (ret) {
+ case -EIO:
+ if (!intel_gt_is_wedged(&dev_priv->gt))
+ return VM_FAULT_SIGBUS;
+ /* fallthrough */
+ case -EAGAIN:
+ case 0:
+ case -ERESTARTSYS:
+ case -EINTR:
+ case -EBUSY:
+ return VM_FAULT_NOPAGE;
+ case -ENOMEM:
+ return VM_FAULT_OOM;
+ case -ENOSPC:
+ case -EFAULT:
+ return VM_FAULT_SIGBUS;
+ default:
+ WARN_ONCE(ret, "unhandled error in %s: %i\n", __func__, ret);
+ return VM_FAULT_SIGBUS;
+ }
+}
+
+void __i915_gem_object_release_mmap_gtt(struct drm_i915_gem_object *obj)
{
struct i915_vma *vma;
struct i915_mmap_offset *mmo;
@@ -380,21 +437,20 @@ void __i915_gem_object_release_mmap(struct drm_i915_gem_object *obj)

obj->userfault_count = 0;
list_del(&obj->userfault_link);
- list_for_each_entry(mmo, &obj->mmap_offsets, offset)
- drm_vma_node_unmap(&mmo->vma_node,
- obj->base.dev->anon_inode->i_mapping);
+
+ mutex_lock(&obj->mmo_lock);
+ list_for_each_entry(mmo, &obj->mmap_offsets, offset) {
+ if (mmo->mmap_type == I915_MMAP_TYPE_GTT)
+ drm_vma_node_unmap(&mmo->vma_node,
+ obj->base.dev->anon_inode->i_mapping);
+ }
+ mutex_unlock(&obj->mmo_lock);

for_each_ggtt_vma(vma, obj)
i915_vma_unset_userfault(vma);
}

/**
- * i915_gem_object_release_mmap - remove physical page mappings
- * @obj: obj in question
- *
- * Preserve the reservation of the mmapping with the DRM core code, but
- * relinquish ownership of the pages back to the system.
- *
* It is vital that we remove the page mapping if we have mapped a tiled
* object through the GTT and then lose the fence register due to
* resource pressure. Similarly if the object has been moved out of the
@@ -402,7 +458,7 @@ void __i915_gem_object_release_mmap(struct drm_i915_gem_object *obj)
* mapping will then trigger a page fault on the next user access, allowing
* fixup by i915_gem_fault().
*/
-void i915_gem_object_release_mmap(struct drm_i915_gem_object *obj)
+static void i915_gem_object_release_mmap_gtt(struct drm_i915_gem_object *obj)
{
struct drm_i915_private *i915 = to_i915(obj->base.dev);
intel_wakeref_t wakeref;
@@ -421,7 +477,7 @@ void i915_gem_object_release_mmap(struct drm_i915_gem_object *obj)
if (!obj->userfault_count)
goto out;

- __i915_gem_object_release_mmap(obj);
+ __i915_gem_object_release_mmap_gtt(obj);

/* Ensure that the CPU's PTE are revoked and there are not outstanding
* memory transactions from userspace before we return. The TLB
@@ -436,6 +492,34 @@ void i915_gem_object_release_mmap(struct drm_i915_gem_object *obj)
intel_runtime_pm_put(&i915->runtime_pm, wakeref);
}

+static void i915_gem_object_release_mmap_offset(struct drm_i915_gem_object *obj)
+{
+ struct i915_mmap_offset *mmo;
+
+ mutex_lock(&obj->mmo_lock);
+ list_for_each_entry(mmo, &obj->mmap_offsets, offset) {
+ if (mmo->mmap_type == I915_MMAP_TYPE_OFFSET_WC ||
+ mmo->mmap_type == I915_MMAP_TYPE_OFFSET_WB ||
+ mmo->mmap_type == I915_MMAP_TYPE_OFFSET_UC)
+ drm_vma_node_unmap(&mmo->vma_node,
+ obj->base.dev->anon_inode->i_mapping);
+ }
+ mutex_unlock(&obj->mmo_lock);
+}
+
+/**
+ * i915_gem_object_release_mmap - remove physical page mappings
+ * @obj: obj in question
+ *
+ * Preserve the reservation of the mmapping with the DRM core code, but
+ * relinquish ownership of the pages back to the system.
+ */
+void i915_gem_object_release_mmap(struct drm_i915_gem_object *obj)
+{
+ i915_gem_object_release_mmap_gtt(obj);
+ i915_gem_object_release_mmap_offset(obj);
+}
+
static void init_mmap_offset(struct drm_i915_gem_object *obj,
struct i915_mmap_offset *mmo)
{
@@ -614,6 +698,42 @@ static const struct vm_operations_struct i915_gem_gtt_vm_ops = {
.close = i915_gem_vm_close,
};

+static const struct vm_operations_struct i915_gem_cpu_vm_ops = {
+ .fault = i915_gem_fault_cpu,
+ .open = i915_gem_vm_open,
+ .close = i915_gem_vm_close,
+};
+
+static const struct vm_operations_struct i915_gem_lmem_vm_ops = {
+ .fault = i915_gem_fault_lmem,
+ .open = i915_gem_vm_open,
+ .close = i915_gem_vm_close,
+};
+
+static void set_vmdata_mmap_offset(struct i915_mmap_offset *mmo, struct vm_area_struct *vma)
+{
+ switch (mmo->mmap_type) {
+ case I915_MMAP_TYPE_OFFSET_WC:
+ vma->vm_page_prot =
+ pgprot_writecombine(vm_get_page_prot(vma->vm_flags));
+ break;
+ case I915_MMAP_TYPE_OFFSET_WB:
+ vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
+ break;
+ case I915_MMAP_TYPE_OFFSET_UC:
+ vma->vm_page_prot =
+ pgprot_noncached(vm_get_page_prot(vma->vm_flags));
+ break;
+ default:
+ break;
+ }
+
+ if (i915_gem_object_is_lmem(mmo->obj))
+ vma->vm_ops = &i915_gem_lmem_vm_ops;
+ else
+ vma->vm_ops = &i915_gem_cpu_vm_ops;
+}
+
/* 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
* be able to resolve multiple mmap offsets which could be tied
@@ -677,7 +797,16 @@ int i915_gem_mmap(struct file *filp, struct vm_area_struct *vma)
vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
vma->vm_private_data = mmo;

- vma->vm_ops = &i915_gem_gtt_vm_ops;
+ switch (mmo->mmap_type) {
+ case I915_MMAP_TYPE_OFFSET_WC:
+ case I915_MMAP_TYPE_OFFSET_WB:
+ case I915_MMAP_TYPE_OFFSET_UC:
+ set_vmdata_mmap_offset(mmo, vma);
+ break;
+ case I915_MMAP_TYPE_GTT:
+ vma->vm_ops = &i915_gem_gtt_vm_ops;
+ break;
+ }

return 0;
}
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h
index 2bb0c779c850..fd58b9aea180 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
@@ -350,7 +350,7 @@ static inline void i915_gem_object_unpin_map(struct drm_i915_gem_object *obj)
i915_gem_object_unpin_pages(obj);
}

-void __i915_gem_object_release_mmap(struct drm_i915_gem_object *obj);
+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);

void
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index af63d1a0af14..5a9bd94b6760 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -871,7 +871,7 @@ void i915_gem_runtime_suspend(struct drm_i915_private *i915)

list_for_each_entry_safe(obj, on,
&i915->ggtt.userfault_list, userfault_link)
- __i915_gem_object_release_mmap(obj);
+ __i915_gem_object_release_mmap_gtt(obj);

/*
* The fence will be lost when the device powers down. If any were