From: Jon Bloomfield <jon.bloomfield@intel.com>
Date: Fri, 8 Jun 2018 08:53:46 -0700
Subject: drm/i915: Disable Secure Batches for gen6+
Git-commit: 44157641d448cbc0c4b73c5231d2b911f0cb0427
Patch-mainline: v5.4-rc8
References: CVE-2019-0154 bsc#1135966 CVE-2019-0155 bsc#1135967 bnc#1151927 5.3.11

Retroactively stop reporting support for secure batches
through the api for gen6+ so that older binaries trigger
the fallback path instead.

Older binaries use secure batches pre gen6 to access resources
that are not available to normal usermode processes. However,
all known userspace explicitly checks for HAS_SECURE_BATCHES
before relying on the secure batch feature.

Since there are no known binaries relying on this for newer gens
we can kill secure batches from gen6, via I915_PARAM_HAS_SECURE_BATCHES.

v2: rebase (Mika)
v3: rebase (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: Jiri Slaby <jslaby@suse.cz>
---
 drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c |   12 ++++++++++--
 drivers/gpu/drm/i915/i915_drv.h                |    1 +
 2 files changed, 11 insertions(+), 2 deletions(-)

--- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
@@ -2384,6 +2384,7 @@ i915_gem_do_execbuffer(struct drm_device
 		       struct drm_i915_gem_exec_object2 *exec,
 		       struct drm_syncobj **fences)
 {
+	struct drm_i915_private *i915 = to_i915(dev);
 	struct i915_execbuffer eb;
 	struct dma_fence *in_fence = NULL;
 	struct dma_fence *exec_fence = NULL;
@@ -2395,7 +2396,7 @@ i915_gem_do_execbuffer(struct drm_device
 	BUILD_BUG_ON(__EXEC_OBJECT_INTERNAL_FLAGS &
 		     ~__EXEC_OBJECT_UNKNOWN_FLAGS);
 
-	eb.i915 = to_i915(dev);
+	eb.i915 = i915;
 	eb.file = file;
 	eb.args = args;
 	if (DBG_FORCE_RELOC || !(args->flags & I915_EXEC_NO_RELOC))
@@ -2415,8 +2416,15 @@ i915_gem_do_execbuffer(struct drm_device
 
 	eb.batch_flags = 0;
 	if (args->flags & I915_EXEC_SECURE) {
+		if (INTEL_GEN(i915) >= 11)
+			return -ENODEV;
+
+		/* Return -EPERM to trigger fallback code on old binaries. */
+		if (!HAS_SECURE_BATCHES(i915))
+			return -EPERM;
+
 		if (!drm_is_current_master(file) || !capable(CAP_SYS_ADMIN))
-		    return -EPERM;
+			return -EPERM;
 
 		eb.batch_flags |= I915_DISPATCH_SECURE;
 	}
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2207,6 +2207,7 @@ IS_SUBPLATFORM(const struct drm_i915_pri
 #define HAS_LLC(dev_priv)	(INTEL_INFO(dev_priv)->has_llc)
 #define HAS_SNOOP(dev_priv)	(INTEL_INFO(dev_priv)->has_snoop)
 #define HAS_EDRAM(dev_priv)	((dev_priv)->edram_size_mb)
+#define HAS_SECURE_BATCHES(dev_priv) (INTEL_GEN(dev_priv) < 6)
 #define HAS_WT(dev_priv)	((IS_HASWELL(dev_priv) || \
 				 IS_BROADWELL(dev_priv)) && HAS_EDRAM(dev_priv))