drm/i915/pxp: interfaces for using protected objects

This api allow user mode to create protected buffers and to mark
contexts as making use of such objects. Only when using contexts
marked in such a way is the execution guaranteed to work as expected.

Contexts can only be marked as using protected content at creation time
(i.e. the parameter is immutable) and they must be both bannable and not
recoverable. Given that the protected session gets invalidated on
suspend, contexts created this way hold a runtime pm wakeref until
they're either destroyed or invalidated.

All protected objects and contexts will be considered invalid when the
PXP session is destroyed and all new submissions using them will be
rejected. All intel contexts within the invalidated gem contexts will be
marked banned. Userspace can detect that an invalidation has occurred via
the RESET_STATS ioctl, where we report it the same way as a ban due to a
hang.

v5: squash patches, rebase on proto_ctx, update kerneldoc

v6: rebase on obj create_ext changes

v7: Use session counter to check if an object it valid, hold wakeref in
    context, don't add a new flag to RESET_STATS (Daniel)

v8: don't increase guilty count for contexts banned during pxp
    invalidation (Rodrigo)

v9: better comments, avoid wakeref put race between pxp_inval and
    context_close, add usage examples (Rodrigo)

v10: modify internal set/get-protected-context functions to not
     return -ENODEV when setting PXP param to false or getting param
     when running on pxp-unsupported hw or getting param when i915
     was built with CONFIG_PXP off

Signed-off-by: Alan Previn <alan.previn.teres.alexis@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Bommu Krishnaiah <krishnaiah.bommu@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: Jason Ekstrand <jason@jlekstrand.net>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210924191452.1539378-11-alan.previn.teres.alexis@intel.com

1 files changed, 54 insertions, 18 deletions

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_create.c b/drivers/gpu/drm/i915/gem/i915_gem_create.c
index 1d341b8c47c0..8955d6abcef1 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_create.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_create.c
@@ -6,6 +6,7 @@
 #include "gem/i915_gem_ioctls.h"
 #include "gem/i915_gem_lmem.h"
 #include "gem/i915_gem_region.h"
+#include "pxp/intel_pxp.h"
 
 #include "i915_drv.h"
 #include "i915_trace.h"
@@ -82,21 +83,11 @@ static int i915_gem_publish(struct drm_i915_gem_object *obj,
 	return 0;
 }
 
-/**
- * Creates a new object using the same path as DRM_I915_GEM_CREATE_EXT
- * @i915: i915 private
- * @size: size of the buffer, in bytes
- * @placements: possible placement regions, in priority order
- * @n_placements: number of possible placement regions
- *
- * This function is exposed primarily for selftests and does very little
- * error checking.  It is assumed that the set of placement regions has
- * already been verified to be valid.
- */
-struct drm_i915_gem_object *
-__i915_gem_object_create_user(struct drm_i915_private *i915, u64 size,
-			      struct intel_memory_region **placements,
-			      unsigned int n_placements)
+static struct drm_i915_gem_object *
+__i915_gem_object_create_user_ext(struct drm_i915_private *i915, u64 size,
+				  struct intel_memory_region **placements,
+				  unsigned int n_placements,
+				  unsigned int ext_flags)
 {
 	struct intel_memory_region *mr = placements[0];
 	struct drm_i915_gem_object *obj;
@@ -135,6 +126,9 @@ __i915_gem_object_create_user(struct drm_i915_private *i915, u64 size,
 
 	GEM_BUG_ON(size != obj->base.size);
 
+	/* Add any flag set by create_ext options */
+	obj->flags |= ext_flags;
+
 	trace_i915_gem_object_create(obj);
 	return obj;
 
@@ -145,6 +139,26 @@ object_free:
 	return ERR_PTR(ret);
 }
 
+/**
+ * Creates a new object using the same path as DRM_I915_GEM_CREATE_EXT
+ * @i915: i915 private
+ * @size: size of the buffer, in bytes
+ * @placements: possible placement regions, in priority order
+ * @n_placements: number of possible placement regions
+ *
+ * This function is exposed primarily for selftests and does very little
+ * error checking.  It is assumed that the set of placement regions has
+ * already been verified to be valid.
+ */
+struct drm_i915_gem_object *
+__i915_gem_object_create_user(struct drm_i915_private *i915, u64 size,
+			      struct intel_memory_region **placements,
+			      unsigned int n_placements)
+{
+	return __i915_gem_object_create_user_ext(i915, size, placements,
+						 n_placements, 0);
+}
+
 int
 i915_gem_dumb_create(struct drm_file *file,
 		     struct drm_device *dev,
@@ -224,6 +238,7 @@ struct create_ext {
 	struct drm_i915_private *i915;
 	struct intel_memory_region *placements[INTEL_REGION_UNKNOWN];
 	unsigned int n_placements;
+	unsigned long flags;
 };
 
 static void repr_placements(char *buf, size_t size,
@@ -353,8 +368,28 @@ static int ext_set_placements(struct i915_user_extension __user *base,
 	return set_placements(&ext, data);
 }
 
+static int ext_set_protected(struct i915_user_extension __user *base, void *data)
+{
+	struct drm_i915_gem_create_ext_protected_content ext;
+	struct create_ext *ext_data = data;
+
+	if (copy_from_user(&ext, base, sizeof(ext)))
+		return -EFAULT;
+
+	if (ext.flags)
+		return -EINVAL;
+
+	if (!intel_pxp_is_enabled(&ext_data->i915->gt.pxp))
+		return -ENODEV;
+
+	ext_data->flags |= I915_BO_PROTECTED;
+
+	return 0;
+}
+
 static const i915_user_extension_fn create_extensions[] = {
 	[I915_GEM_CREATE_EXT_MEMORY_REGIONS] = ext_set_placements,
+	[I915_GEM_CREATE_EXT_PROTECTED_CONTENT] = ext_set_protected,
 };
 
 /**
@@ -389,9 +424,10 @@ i915_gem_create_ext_ioctl(struct drm_device *dev, void *data,
 		ext_data.n_placements = 1;
 	}
 
-	obj = __i915_gem_object_create_user(i915, args->size,
-					    ext_data.placements,
-					    ext_data.n_placements);
+	obj = __i915_gem_object_create_user_ext(i915, args->size,
+						ext_data.placements,
+						ext_data.n_placements,
+						ext_data.flags);
 	if (IS_ERR(obj))
 		return PTR_ERR(obj);