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

["Ceraolo Spurio, Daniele" <daniele.ceraolospurio@intel.com>]

On 4/20/2023 6:15 PM, John.C.Harrison@Intel.com wrote:
> From: John Harrison <John.C.Harrison@Intel.com>
>
> 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.
>
> v2: Change to unconditionally fail module load on a validation error
> (review feedback/discussion with Daniele).
>
> Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
> ---
>   drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c | 157 +++++++++++++----------
>   1 file changed, 92 insertions(+), 65 deletions(-)
>
> 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 c9cd9bb47577f..eb52e8db9ae0b 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)
> @@ -443,6 +465,11 @@ 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)) {
> +			intel_uc_fw_change_status(uc_fw, INTEL_UC_FIRMWARE_ERROR);

In our hierarchy of firmware statuses, INTEL_UC_FIRMWARE_ERROR includes 
the fact that the fw has been selected, which in turns implies that 
file_selected.path is valid. this means that even with enable_guc=0 the 
wants/uses_guc macro might end up returning true, which is not something 
we want.

Daniele

> +			return;
> +		}
> +
>   		__uc_fw_auto_select(i915, uc_fw);
>   		__uc_fw_user_override(i915, uc_fw);
>   	}