Re: [PATCH v3 4/6] drm/i915/uc: Enhancements to firmware table validation

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On 5/3/2023 1:40 AM, John.C.Harrison@xxxxxxxxx wrote:

From: John Harrison <John.C.Harrison@xxxxxxxxx>

The validation of the firmware table was being done inside the code
for scanning the table for the next available firmware blob. Which is
unnecessary. So pull it out into a separate function that is only
called once per blob type at init time.

Also, drop the CONFIG_SELFTEST requirement and make errors terminal.
It was mentioned that potential issues with backports would not be
caught by regular pre-merge CI as that only occurs on tip not stable
branches. Making the validation unconditional and failing driver load
on detecting of a problem ensures that such backports will also be
validated correctly.

This requires adding a firmware global flag to indicate an issue with
any of the per firmware tables. This is done rather than adding a new
state enum as a new enum value would be a much more invasive change -
lots of places would need updating to support the new error state.

Note also that this change means that a table error will cause the
driver to wedge even on platforms that don't require firmware files.
This is intentional as per the above backport concern - someone doing
backports is not guaranteed to test on every platform that they may
potential affect. So forcing a failure on all platforms ensures that
the problem will be noticed and corrected immediately.

v2: Change to unconditionally fail module load on a validation error
(review feedback/discussion with Daniele).
v3: Add a new flag to track table validation errors (review
feedback/discussion with Daniele).

Signed-off-by: John Harrison <John.C.Harrison@xxxxxxxxx>


Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@xxxxxxxxx>

Daniele


---
  drivers/gpu/drm/i915/gt/uc/intel_uc.c    |   3 +
  drivers/gpu/drm/i915/gt/uc/intel_uc.h    |   1 +
  drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c | 161 +++++++++++++----------
  3 files changed, 99 insertions(+), 66 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc.c b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
index 996168312340e..1381943b8973d 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_uc.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_uc.c
@@ -432,6 +432,9 @@ static bool uc_is_wopcm_locked(struct intel_uc *uc)
static int __uc_check_hw(struct intel_uc *uc) 
  {
+	if (uc->fw_table_invalid)
+		return -EIO;
+
  	if (!intel_uc_supports_guc(uc))
  		return 0;
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc.h b/drivers/gpu/drm/i915/gt/uc/intel_uc.h 
index 5d0f1bcc381e8..d585524d94deb 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_uc.h
+++ b/drivers/gpu/drm/i915/gt/uc/intel_uc.h
@@ -36,6 +36,7 @@ struct intel_uc {
  	struct drm_i915_gem_object *load_err_log;
bool reset_in_progress; 
+	bool fw_table_invalid;
  };
void intel_uc_init_early(struct intel_uc *uc); 
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c b/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c
index 55e50bd08d7ff..64e19688788d1 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c
@@ -233,20 +233,22 @@ struct fw_blobs_by_type {
  	u32 count;
  };
+static const struct uc_fw_platform_requirement blobs_guc[] = { 
+	INTEL_GUC_FIRMWARE_DEFS(MAKE_FW_LIST, GUC_FW_BLOB, GUC_FW_BLOB_MMP)
+};
+
+static const struct uc_fw_platform_requirement blobs_huc[] = {
+	INTEL_HUC_FIRMWARE_DEFS(MAKE_FW_LIST, HUC_FW_BLOB, HUC_FW_BLOB_MMP, HUC_FW_BLOB_GSC)
+};
+
+static const struct fw_blobs_by_type blobs_all[INTEL_UC_FW_NUM_TYPES] = {
+	[INTEL_UC_FW_TYPE_GUC] = { blobs_guc, ARRAY_SIZE(blobs_guc) },
+	[INTEL_UC_FW_TYPE_HUC] = { blobs_huc, ARRAY_SIZE(blobs_huc) },
+};
+
  static void
  __uc_fw_auto_select(struct drm_i915_private *i915, struct intel_uc_fw *uc_fw)
  {
-	static const struct uc_fw_platform_requirement blobs_guc[] = {
-		INTEL_GUC_FIRMWARE_DEFS(MAKE_FW_LIST, GUC_FW_BLOB, GUC_FW_BLOB_MMP)
-	};
-	static const struct uc_fw_platform_requirement blobs_huc[] = {
-		INTEL_HUC_FIRMWARE_DEFS(MAKE_FW_LIST, HUC_FW_BLOB, HUC_FW_BLOB_MMP, HUC_FW_BLOB_GSC)
-	};
-	static const struct fw_blobs_by_type blobs_all[INTEL_UC_FW_NUM_TYPES] = {
-		[INTEL_UC_FW_TYPE_GUC] = { blobs_guc, ARRAY_SIZE(blobs_guc) },
-		[INTEL_UC_FW_TYPE_HUC] = { blobs_huc, ARRAY_SIZE(blobs_huc) },
-	};
-	static bool verified[INTEL_UC_FW_NUM_TYPES];
  	const struct uc_fw_platform_requirement *fw_blobs;
  	enum intel_platform p = INTEL_INFO(i915)->platform;
  	u32 fw_count;
@@ -286,6 +288,11 @@ __uc_fw_auto_select(struct drm_i915_private *i915, struct intel_uc_fw *uc_fw)
  			continue;
if (uc_fw->file_selected.path) { 
+			/*
+			 * Continuing an earlier search after a found blob failed to load.
+			 * Once the previously chosen path has been found, clear it out
+			 * and let the search continue from there.
+			 */
  			if (uc_fw->file_selected.path == blob->path)
  				uc_fw->file_selected.path = NULL;
@@ -306,76 +313,91 @@ __uc_fw_auto_select(struct drm_i915_private *i915, struct intel_uc_fw *uc_fw) 
  		/* Failed to find a match for the last attempt?! */
  		uc_fw->file_selected.path = NULL;
  	}
+}
- /* make sure the list is ordered as expected */ 
-	if (IS_ENABLED(CONFIG_DRM_I915_SELFTEST) && !verified[uc_fw->type]) {
-		verified[uc_fw->type] = true;
+static bool validate_fw_table_type(struct drm_i915_private *i915, enum intel_uc_fw_type type)
+{
+	const struct uc_fw_platform_requirement *fw_blobs;
+	u32 fw_count;
+	int i;
- for (i = 1; i < fw_count; i++) { 
-			/* Next platform is good: */
-			if (fw_blobs[i].p < fw_blobs[i - 1].p)
-				continue;
+	if (type >= ARRAY_SIZE(blobs_all)) {
+		drm_err(&i915->drm, "No blob array for %s\n", intel_uc_fw_type_repr(type));
+		return false;
+	}
- /* Next platform revision is good: */ 
-			if (fw_blobs[i].p == fw_blobs[i - 1].p &&
-			    fw_blobs[i].rev < fw_blobs[i - 1].rev)
-				continue;
+	fw_blobs = blobs_all[type].blobs;
+	fw_count = blobs_all[type].count;
- /* Platform/revision must be in order: */ 
-			if (fw_blobs[i].p != fw_blobs[i - 1].p ||
-			    fw_blobs[i].rev != fw_blobs[i - 1].rev)
-				goto bad;
+	if (!fw_count)
+		return true;
- /* Next major version is good: */ 
-			if (fw_blobs[i].blob.major < fw_blobs[i - 1].blob.major)
-				continue;
+	/* make sure the list is ordered as expected */
+	for (i = 1; i < fw_count; i++) {
+		/* Next platform is good: */
+		if (fw_blobs[i].p < fw_blobs[i - 1].p)
+			continue;
- /* New must be before legacy: */ 
-			if (!fw_blobs[i].blob.legacy && fw_blobs[i - 1].blob.legacy)
-				goto bad;
+		/* Next platform revision is good: */
+		if (fw_blobs[i].p == fw_blobs[i - 1].p &&
+		    fw_blobs[i].rev < fw_blobs[i - 1].rev)
+			continue;
- /* New to legacy also means 0.0 to X.Y (HuC), or X.0 to X.Y (GuC) */ 
-			if (fw_blobs[i].blob.legacy && !fw_blobs[i - 1].blob.legacy) {
-				if (!fw_blobs[i - 1].blob.major)
-					continue;
+		/* Platform/revision must be in order: */
+		if (fw_blobs[i].p != fw_blobs[i - 1].p ||
+		    fw_blobs[i].rev != fw_blobs[i - 1].rev)
+			goto bad;
- if (fw_blobs[i].blob.major == fw_blobs[i - 1].blob.major) 
-					continue;
-			}
+		/* Next major version is good: */
+		if (fw_blobs[i].blob.major < fw_blobs[i - 1].blob.major)
+			continue;
- /* Major versions must be in order: */ 
-			if (fw_blobs[i].blob.major != fw_blobs[i - 1].blob.major)
-				goto bad;
+		/* New must be before legacy: */
+		if (!fw_blobs[i].blob.legacy && fw_blobs[i - 1].blob.legacy)
+			goto bad;
- /* Next minor version is good: */ 
-			if (fw_blobs[i].blob.minor < fw_blobs[i - 1].blob.minor)
+		/* New to legacy also means 0.0 to X.Y (HuC), or X.0 to X.Y (GuC) */
+		if (fw_blobs[i].blob.legacy && !fw_blobs[i - 1].blob.legacy) {
+			if (!fw_blobs[i - 1].blob.major)
  				continue;
- /* Minor versions must be in order: */ 
-			if (fw_blobs[i].blob.minor != fw_blobs[i - 1].blob.minor)
-				goto bad;
-
-			/* Patch versions must be in order: */
-			if (fw_blobs[i].blob.patch <= fw_blobs[i - 1].blob.patch)
+			if (fw_blobs[i].blob.major == fw_blobs[i - 1].blob.major)
  				continue;
+		}
+
+		/* Major versions must be in order: */
+		if (fw_blobs[i].blob.major != fw_blobs[i - 1].blob.major)
+			goto bad;
+
+		/* Next minor version is good: */
+		if (fw_blobs[i].blob.minor < fw_blobs[i - 1].blob.minor)
+			continue;
+
+		/* Minor versions must be in order: */
+		if (fw_blobs[i].blob.minor != fw_blobs[i - 1].blob.minor)
+			goto bad;
+
+		/* Patch versions must be in order: */
+		if (fw_blobs[i].blob.patch <= fw_blobs[i - 1].blob.patch)
+			continue;
bad: 
-			drm_err(&i915->drm, "Invalid %s blob order: %s r%u %s%d.%d.%d comes before %s r%u %s%d.%d.%d\n",
-				intel_uc_fw_type_repr(uc_fw->type),
-				intel_platform_name(fw_blobs[i - 1].p), fw_blobs[i - 1].rev,
-				fw_blobs[i - 1].blob.legacy ? "L" : "v",
-				fw_blobs[i - 1].blob.major,
-				fw_blobs[i - 1].blob.minor,
-				fw_blobs[i - 1].blob.patch,
-				intel_platform_name(fw_blobs[i].p), fw_blobs[i].rev,
-				fw_blobs[i].blob.legacy ? "L" : "v",
-				fw_blobs[i].blob.major,
-				fw_blobs[i].blob.minor,
-				fw_blobs[i].blob.patch);
-
-			uc_fw->file_selected.path = NULL;
-		}
+		drm_err(&i915->drm, "Invalid %s blob order: %s r%u %s%d.%d.%d comes before %s r%u %s%d.%d.%d\n",
+			intel_uc_fw_type_repr(type),
+			intel_platform_name(fw_blobs[i - 1].p), fw_blobs[i - 1].rev,
+			fw_blobs[i - 1].blob.legacy ? "L" : "v",
+			fw_blobs[i - 1].blob.major,
+			fw_blobs[i - 1].blob.minor,
+			fw_blobs[i - 1].blob.patch,
+			intel_platform_name(fw_blobs[i].p), fw_blobs[i].rev,
+			fw_blobs[i].blob.legacy ? "L" : "v",
+			fw_blobs[i].blob.major,
+			fw_blobs[i].blob.minor,
+			fw_blobs[i].blob.patch);
+		return false;
  	}
+
+	return true;
  }
static const char *__override_guc_firmware_path(struct drm_i915_private *i915) 
@@ -430,7 +452,8 @@ static void __uc_fw_user_override(struct drm_i915_private *i915, struct intel_uc
  void intel_uc_fw_init_early(struct intel_uc_fw *uc_fw,
  			    enum intel_uc_fw_type type)
  {
-	struct drm_i915_private *i915 = ____uc_fw_to_gt(uc_fw, type)->i915;
+	struct intel_gt *gt = ____uc_fw_to_gt(uc_fw, type);
+	struct drm_i915_private *i915 = gt->i915;
/* 
  	 * we use FIRMWARE_UNINITIALIZED to detect checks against uc_fw->status
@@ -443,6 +466,12 @@ void intel_uc_fw_init_early(struct intel_uc_fw *uc_fw,
  	uc_fw->type = type;
if (HAS_GT_UC(i915)) { 
+		if (!validate_fw_table_type(i915, type)) {
+			gt->uc.fw_table_invalid = true;
+			intel_uc_fw_change_status(uc_fw, INTEL_UC_FIRMWARE_NOT_SUPPORTED);
+			return;
+		}
+
  		__uc_fw_auto_select(i915, uc_fw);
  		__uc_fw_user_override(i915, uc_fw);
  	}
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