[PATCH v2 29/37] drm/i915: Introduce DRM_I915_GEM_MMAP_OFFSET

[Matthew Auld <matthew.auld@intel.com>]

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

Add a new CPU mmap implementation that allows multiple fault handlers
that depends on the object's backing pages.

Note that we multiplex mmap_gtt and mmap_offset through the same ioctl,
and use the zero extending behaviour of drm to differentiate between
them, when we inspect the flags.

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_ioctls.h    |  2 ++
 drivers/gpu/drm/i915/gem/i915_gem_mman.c      | 30 ++++++++++++++++++
 .../gpu/drm/i915/gem/i915_gem_object_types.h  |  3 ++
 drivers/gpu/drm/i915/i915_drv.c               |  3 +-
 include/uapi/drm/i915_drm.h                   | 31 +++++++++++++++++++
 5 files changed, 68 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ioctls.h b/drivers/gpu/drm/i915/gem/i915_gem_ioctls.h
index ddc7f2a52b3e..5abd5b2172f2 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ioctls.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ioctls.h
@@ -30,6 +30,8 @@ int i915_gem_mmap_ioctl(struct drm_device *dev, void *data,
 			struct drm_file *file);
 int i915_gem_mmap_gtt_ioctl(struct drm_device *dev, void *data,
 			    struct drm_file *file);
+int i915_gem_mmap_offset_ioctl(struct drm_device *dev, void *data,
+			       struct drm_file *file_priv);
 int i915_gem_pread_ioctl(struct drm_device *dev, void *data,
 			 struct drm_file *file);
 int i915_gem_pwrite_ioctl(struct drm_device *dev, void *data,
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
index 7b46f44d9c20..cbf89e80a97b 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
@@ -536,12 +536,42 @@ i915_gem_mmap_gtt_ioctl(struct drm_device *dev, void *data,
 			struct drm_file *file)
 {
 	struct drm_i915_gem_mmap_offset *args = data;
+	struct drm_i915_private *i915 = to_i915(dev);
+
+	if (args->flags & I915_MMAP_OFFSET_FLAGS)
+		return i915_gem_mmap_offset_ioctl(dev, data, file);
+
+	if (!HAS_MAPPABLE_APERTURE(i915)) {
+		DRM_ERROR("No aperture, cannot mmap via legacy GTT\n");
+		return -ENODEV;
+	}
 
 	return __assign_gem_object_mmap_data(file, args->handle,
 					     I915_MMAP_TYPE_GTT,
 					     &args->offset);
 }
 
+int i915_gem_mmap_offset_ioctl(struct drm_device *dev, void *data,
+			       struct drm_file *file)
+{
+	struct drm_i915_gem_mmap_offset *args = data;
+	enum i915_mmap_type type;
+
+	if ((args->flags & (I915_MMAP_OFFSET_WC | I915_MMAP_OFFSET_WB)) &&
+	    !boot_cpu_has(X86_FEATURE_PAT))
+		return -ENODEV;
+
+	if (args->flags & I915_MMAP_OFFSET_WC)
+		type = I915_MMAP_TYPE_OFFSET_WC;
+	else if (args->flags & I915_MMAP_OFFSET_WB)
+		type = I915_MMAP_TYPE_OFFSET_WB;
+	else if (args->flags & I915_MMAP_OFFSET_UC)
+		type = I915_MMAP_TYPE_OFFSET_UC;
+
+	return __assign_gem_object_mmap_data(file, args->handle, type,
+					     &args->offset);
+}
+
 void i915_mmap_offset_object_release(struct kref *ref)
 {
 	struct i915_mmap_offset *mmo = container_of(ref,
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
index 86f358da8085..f95e54a25426 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object_types.h
@@ -63,6 +63,9 @@ struct drm_i915_gem_object_ops {
 
 enum i915_mmap_type {
 	I915_MMAP_TYPE_GTT = 0,
+	I915_MMAP_TYPE_OFFSET_WC,
+	I915_MMAP_TYPE_OFFSET_WB,
+	I915_MMAP_TYPE_OFFSET_UC,
 };
 
 struct i915_mmap_offset {
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 0f1f3b7f3029..8dadd6b9a0a9 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -459,6 +459,7 @@ static int i915_getparam_ioctl(struct drm_device *dev, void *data,
 	case I915_PARAM_HAS_EXEC_BATCH_FIRST:
 	case I915_PARAM_HAS_EXEC_FENCE_ARRAY:
 	case I915_PARAM_HAS_EXEC_SUBMIT_FENCE:
+	case I915_PARAM_MMAP_OFFSET_VERSION:
 		/* For the time being all of these are always true;
 		 * if some supported hardware does not have one of these
 		 * features this value needs to be provided from
@@ -3176,7 +3177,7 @@ static const struct drm_ioctl_desc i915_ioctls[] = {
 	DRM_IOCTL_DEF_DRV(I915_GEM_PREAD, i915_gem_pread_ioctl, DRM_RENDER_ALLOW),
 	DRM_IOCTL_DEF_DRV(I915_GEM_PWRITE, i915_gem_pwrite_ioctl, DRM_RENDER_ALLOW),
 	DRM_IOCTL_DEF_DRV(I915_GEM_MMAP, i915_gem_mmap_ioctl, DRM_RENDER_ALLOW),
-	DRM_IOCTL_DEF_DRV(I915_GEM_MMAP_GTT, i915_gem_mmap_gtt_ioctl, DRM_RENDER_ALLOW),
+	DRM_IOCTL_DEF_DRV(I915_GEM_MMAP_OFFSET, i915_gem_mmap_gtt_ioctl, DRM_RENDER_ALLOW),
 	DRM_IOCTL_DEF_DRV(I915_GEM_SET_DOMAIN, i915_gem_set_domain_ioctl, DRM_RENDER_ALLOW),
 	DRM_IOCTL_DEF_DRV(I915_GEM_SW_FINISH, i915_gem_sw_finish_ioctl, DRM_RENDER_ALLOW),
 	DRM_IOCTL_DEF_DRV(I915_GEM_SET_TILING, i915_gem_set_tiling_ioctl, DRM_RENDER_ALLOW),
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 328d05e77d9f..729e729e2282 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -359,6 +359,7 @@ typedef struct _drm_i915_sarea {
 #define DRM_I915_QUERY			0x39
 #define DRM_I915_GEM_VM_CREATE		0x3a
 #define DRM_I915_GEM_VM_DESTROY		0x3b
+#define DRM_I915_GEM_MMAP_OFFSET   	DRM_I915_GEM_MMAP_GTT
 /* Must be kept compact -- no holes */
 
 #define DRM_IOCTL_I915_INIT		DRM_IOW( DRM_COMMAND_BASE + DRM_I915_INIT, drm_i915_init_t)
@@ -421,6 +422,7 @@ typedef struct _drm_i915_sarea {
 #define DRM_IOCTL_I915_QUERY			DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_QUERY, struct drm_i915_query)
 #define DRM_IOCTL_I915_GEM_VM_CREATE	DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GEM_VM_CREATE, struct drm_i915_gem_vm_control)
 #define DRM_IOCTL_I915_GEM_VM_DESTROY	DRM_IOW (DRM_COMMAND_BASE + DRM_I915_GEM_VM_DESTROY, struct drm_i915_gem_vm_control)
+#define DRM_IOCTL_I915_GEM_MMAP_OFFSET		DRM_IOWR(DRM_COMMAND_BASE + DRM_I915_GEM_MMAP_OFFSET, struct drm_i915_gem_mmap_offset)
 
 /* Allow drivers to submit batchbuffers directly to hardware, relying
  * on the security mechanisms provided by hardware.
@@ -610,6 +612,10 @@ typedef struct drm_i915_irq_wait {
  * See I915_EXEC_FENCE_OUT and I915_EXEC_FENCE_SUBMIT.
  */
 #define I915_PARAM_HAS_EXEC_SUBMIT_FENCE 53
+
+/* Mmap offset ioctl */
+#define I915_PARAM_MMAP_OFFSET_VERSION	54
+
 /* Must be kept compact -- no holes and well documented */
 
 typedef struct drm_i915_getparam {
@@ -785,6 +791,31 @@ struct drm_i915_gem_mmap_gtt {
 	__u64 offset;
 };
 
+struct drm_i915_gem_mmap_offset {
+	/** Handle for the object being mapped. */
+	__u32 handle;
+	__u32 pad;
+	/**
+	 * Fake offset to use for subsequent mmap call
+	 *
+	 * This is a fixed-size type for 32/64 compatibility.
+	 */
+	__u64 offset;
+
+	/**
+	 * Flags for extended behaviour.
+	 *
+	 * It is mandatory that either one of the _WC/_WB flags
+	 * should be passed here.
+	 */
+	__u64 flags;
+#define I915_MMAP_OFFSET_WC (1 << 0)
+#define I915_MMAP_OFFSET_WB (1 << 1)
+#define I915_MMAP_OFFSET_UC (1 << 2)
+#define I915_MMAP_OFFSET_FLAGS \
+	(I915_MMAP_OFFSET_WC | I915_MMAP_OFFSET_WB | I915_MMAP_OFFSET_UC)
+};
+
 struct drm_i915_gem_set_domain {
 	/** Handle for the object */
 	__u32 handle;
-- 
2.20.1

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