[RFC] drm/i915: Add GuC submission interface version query

[John Harrison]

On 2/7/2024 03:56, Tvrtko Ursulin wrote:
> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
>
> Add a new query to the GuC submission interface version.
>
> Mesa intends to use this information to check for old firmware versions
> with a known bug where using the render and compute command streamers
> simultaneously can cause GPU hangs due issues in firmware scheduling.
>
> Based on patches from Vivaik and Joonas.
>
> There is a little bit of an open around the width required for versions.
> While the GuC FW iface tells they are u8, i915 GuC code uses u32:
>
>   #define CSS_SW_VERSION_UC_MAJOR               (0xFF << 16)
>   #define CSS_SW_VERSION_UC_MINOR               (0xFF << 8)
>   #define CSS_SW_VERSION_UC_PATCH               (0xFF << 0)
> ...
>   struct intel_uc_fw_ver {
>           u32 major;
>           u32 minor;
>           u32 patch;
>           u32 build;
>   };
This is copied from generic code which supports firmwares other than 
GuC. Only GuC promises to use 8-bit version components. Other firmwares 
very definitely do not. There is no open.

>
> So we could make the query u8, and refactor the struct intel_uc_fw_ver
> to use u8, or not. To avoid any doubts on why are we assigning u32 to
> u8 I simply opted to use u64. Which avoids the need to add any padding
> too.
I don't follow how potential 8 vs 32 confusion means jump to 64?!

>
> Compile tested only.
>
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> Cc: Kenneth Graunke <kenneth at whitecape.org>
> Cc: Jose Souza <jose.souza at intel.com>
> Cc: Sagar Ghuge <sagar.ghuge at intel.com>
> Cc: Paulo Zanoni <paulo.r.zanoni at intel.com>
> Cc: John Harrison <John.C.Harrison at Intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> Cc: Jani Nikula <jani.nikula at intel.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> Cc: Vivaik Balasubrawmanian <vivaik.balasubrawmanian at intel.com>
> ---
>   drivers/gpu/drm/i915/i915_query.c | 32 +++++++++++++++++++++++++++++++
>   include/uapi/drm/i915_drm.h       | 11 +++++++++++
>   2 files changed, 43 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_query.c b/drivers/gpu/drm/i915/i915_query.c
> index 00871ef99792..999687f6a3d4 100644
> --- a/drivers/gpu/drm/i915/i915_query.c
> +++ b/drivers/gpu/drm/i915/i915_query.c
> @@ -551,6 +551,37 @@ static int query_hwconfig_blob(struct drm_i915_private *i915,
>   	return hwconfig->size;
>   }
>   
> +static int
> +query_guc_submission_version(struct drm_i915_private *i915,
> +			     struct drm_i915_query_item *query)
> +{
> +	struct drm_i915_query_guc_submission_version __user *query_ptr =
> +					    u64_to_user_ptr(query->data_ptr);
> +	struct drm_i915_query_guc_submission_version ver;
> +	struct intel_guc *guc = &to_gt(i915)->uc.guc;
> +	const size_t size = sizeof(ver);
> +	int ret;
> +
> +	if (!intel_uc_uses_guc_submission(&to_gt(i915)->uc))
> +		return -ENODEV;
> +
> +	ret = copy_query_item(&ver, size, size, query);
> +	if (ret != 0)
> +		return ret;
> +
> +	if (ver.major || ver.minor || ver.patch)
> +		return -EINVAL;
> +
> +	ver.major = guc->submission_version.major;
> +	ver.minor = guc->submission_version.minor;
> +	ver.patch = guc->submission_version.patch;
This needs to include the branch version (currently set to zero) in the 
definition. And the UMD needs to barf if branch comes back as non-zero. 
I.e. there is no guarantee that a branched version will have the w/a + 
fix that they are wanting.

John.


> +
> +	if (copy_to_user(query_ptr, &ver, size))
> +		return -EFAULT;
> +
> +	return 0;
> +}
> +
>   static int (* const i915_query_funcs[])(struct drm_i915_private *dev_priv,
>   					struct drm_i915_query_item *query_item) = {
>   	query_topology_info,
> @@ -559,6 +590,7 @@ static int (* const i915_query_funcs[])(struct drm_i915_private *dev_priv,
>   	query_memregion_info,
>   	query_hwconfig_blob,
>   	query_geometry_subslices,
> +	query_guc_submission_version,
>   };
>   
>   int i915_query_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
> diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
> index 550c496ce76d..d80d9b5e1eda 100644
> --- a/include/uapi/drm/i915_drm.h
> +++ b/include/uapi/drm/i915_drm.h
> @@ -3038,6 +3038,7 @@ struct drm_i915_query_item {
>   	 *  - %DRM_I915_QUERY_MEMORY_REGIONS (see struct drm_i915_query_memory_regions)
>   	 *  - %DRM_I915_QUERY_HWCONFIG_BLOB (see `GuC HWCONFIG blob uAPI`)
>   	 *  - %DRM_I915_QUERY_GEOMETRY_SUBSLICES (see struct drm_i915_query_topology_info)
> +	 *  - %DRM_I915_QUERY_GUC_SUBMISSION_VERSION (see struct drm_i915_query_guc_submission_version)
>   	 */
>   	__u64 query_id;
>   #define DRM_I915_QUERY_TOPOLOGY_INFO		1
> @@ -3046,6 +3047,7 @@ struct drm_i915_query_item {
>   #define DRM_I915_QUERY_MEMORY_REGIONS		4
>   #define DRM_I915_QUERY_HWCONFIG_BLOB		5
>   #define DRM_I915_QUERY_GEOMETRY_SUBSLICES	6
> +#define DRM_I915_QUERY_GUC_SUBMISSION_VERSION	7
>   /* Must be kept compact -- no holes and well documented */
>   
>   	/**
> @@ -3591,6 +3593,15 @@ struct drm_i915_query_memory_regions {
>   	struct drm_i915_memory_region_info regions[];
>   };
>   
> +/**
> +* struct drm_i915_query_guc_submission_version - query GuC submission interface version
> +*/
> +struct drm_i915_query_guc_submission_version {
> +	__u64 major;
> +	__u64 minor;
> +	__u64 patch;
> +};
> +
>   /**
>    * DOC: GuC HWCONFIG blob uAPI
>    *