drm/i915: Add support for mandatory cmdparsing

commit 311a50e76a33d1e029563c24b2ff6db0c02b5afe upstream.

The existing cmdparser for gen7 can be bypassed by specifying
batch_len=0 in the execbuf call. This is safe because bypassing
simply reduces the cmd-set available.

In a later patch we will introduce cmdparsing for gen9, as a
security measure, which must be strictly enforced since without
it we are vulnerable to DoS attacks.

Introduce the concept of 'required' cmd parsing that cannot be
bypassed by submitting zero-length bb's.

v2: rebase (Mika)
v2: rebase (Mika)
v3: fix conflict on engine flags (Mika)

Signed-off-by: Jon Bloomfield <jon.bloomfield@intel.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Tyler Hicks <tyhicks@canonical.com>
Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Chris Wilson <chris.p.wilson@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/i915/i915_cmd_parser.c b/drivers/gpu/drm/i915/i915_cmd_parser.c
index 462d0f700a8caeaacb6f2cc3e5a1d23752058ac5..da91d3650dead0776799cc90d6868725323c819c 100644 (file)
--- a/drivers/gpu/drm/i915/i915_cmd_parser.c
+++ b/drivers/gpu/drm/i915/i915_cmd_parser.c
@@ -916,7 +916,7 @@ void intel_engine_init_cmd_parser(struct intel_engine_cs *engine)
                return;
        }
 
-       engine->flags |= I915_ENGINE_NEEDS_CMD_PARSER;
+       engine->flags |= I915_ENGINE_USING_CMD_PARSER;
 }
 
 /**
@@ -928,7 +928,7 @@ void intel_engine_init_cmd_parser(struct intel_engine_cs *engine)
  */
 void intel_engine_cleanup_cmd_parser(struct intel_engine_cs *engine)
 {
-       if (!intel_engine_needs_cmd_parser(engine))
+       if (!intel_engine_using_cmd_parser(engine))
                return;
 
        fini_hash_table(engine);
@@ -1316,7 +1316,7 @@ int i915_cmd_parser_get_version(struct drm_i915_private *dev_priv)
 
        /* If the command parser is not enabled, report 0 - unsupported */
        for_each_engine(engine, dev_priv) {
-               if (intel_engine_needs_cmd_parser(engine)) {
+               if (intel_engine_using_cmd_parser(engine)) {
                        active = true;
                        break;
                }

diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
index 1f5e64190fff5d98c005bb46ea1a85611fa846d4..069f26a3f3ba9b8564a03307506b6293149052fd 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c
@@ -1716,7 +1716,8 @@ i915_gem_do_execbuffer(struct drm_device *dev, void *data,
        }
 
        params->args_batch_start_offset = args->batch_start_offset;
-       if (intel_engine_needs_cmd_parser(engine) && args->batch_len) {
+       if (intel_engine_requires_cmd_parser(engine) ||
+           (intel_engine_using_cmd_parser(engine) && args->batch_len)) {
                struct i915_vma *vma;
 
                vma = i915_gem_execbuffer_parse(engine, &shadow_exec_entry,

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index e24d1324f0941667191103398e6ada679364f8dc..ce14cd8495e8e717871c436f1ad0c9e1b47e958a 100644 (file)
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -341,7 +341,8 @@ struct intel_engine_cs {
 
        struct intel_engine_hangcheck hangcheck;
 
-#define I915_ENGINE_NEEDS_CMD_PARSER BIT(0)
+#define I915_ENGINE_USING_CMD_PARSER   BIT(0)
+#define I915_ENGINE_REQUIRES_CMD_PARSER        BIT(3)
        unsigned int flags;
 
        /*
@@ -375,9 +376,16 @@ intel_engine_initialized(const struct intel_engine_cs *engine)
        return engine->i915 != NULL;
 }
 
-static inline bool intel_engine_needs_cmd_parser(struct intel_engine_cs *engine)
+static inline bool
+intel_engine_using_cmd_parser(const struct intel_engine_cs *engine)
+{
+       return engine->flags & I915_ENGINE_USING_CMD_PARSER;
+}
+
+static inline bool
+intel_engine_requires_cmd_parser(const struct intel_engine_cs *engine)
 {
-       return engine->flags & I915_ENGINE_NEEDS_CMD_PARSER;
+       return engine->flags & I915_ENGINE_REQUIRES_CMD_PARSER;
 }
 
 static inline unsigned int