drm/i915/huc: check HuC and GuC version compatibility on MTL

Due to a change in the auth flow on MTL, GuC 70.7.0 and newer will only
be able to authenticate HuC 8.5.1 and newer. The plan is to update the 2
binaries synchronously in linux-firmware so that the fw repo always has
a matching pair that works; still, it's better to check in the kernel so
we can print an error message and abort HuC loading if the binaries are
out of sync instead of failing the authentication.

v2: Add clarification comment, fix typo in commit msg, clean up variable
declaration (John)

Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: Andrzej Hajda <andrzej.hajda@intel.com> #v1
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230717234905.117114-1-daniele.ceraolospurio@intel.com

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 d408856..3621963 100644 (file)
--- a/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_uc_fw.c
@@ -787,11 +787,57 @@ static int try_firmware_load(struct intel_uc_fw *uc_fw, const struct firmware **
        return 0;
 }
 
+static int check_mtl_huc_guc_compatibility(struct intel_gt *gt,
+                                          struct intel_uc_fw_file *huc_selected)
+{
+       struct intel_uc_fw_file *guc_selected = &gt->uc.guc.fw.file_selected;
+       struct intel_uc_fw_ver *huc_ver = &huc_selected->ver;
+       struct intel_uc_fw_ver *guc_ver = &guc_selected->ver;
+       bool new_huc, new_guc;
+
+       /* we can only do this check after having fetched both GuC and HuC */
+       GEM_BUG_ON(!huc_selected->path || !guc_selected->path);
+
+       /*
+        * Due to changes in the authentication flow for MTL, HuC 8.5.1 or newer
+        * requires GuC 70.7.0 or newer. Older HuC binaries will instead require
+        * GuC < 70.7.0.
+        */
+       new_huc = huc_ver->major > 8 ||
+                 (huc_ver->major == 8 && huc_ver->minor > 5) ||
+                 (huc_ver->major == 8 && huc_ver->minor == 5 && huc_ver->patch >= 1);
+
+       new_guc = guc_ver->major > 70 ||
+                 (guc_ver->major == 70 && guc_ver->minor >= 7);
+
+       if (new_huc != new_guc) {
+               UNEXPECTED(gt, "HuC %u.%u.%u is incompatible with GuC %u.%u.%u\n",
+                          huc_ver->major, huc_ver->minor, huc_ver->patch,
+                          guc_ver->major, guc_ver->minor, guc_ver->patch);
+               gt_info(gt, "MTL GuC 70.7.0+ and HuC 8.5.1+ don't work with older releases\n");
+               return -ENOEXEC;
+       }
+
+       return 0;
+}
+
 int intel_uc_check_file_version(struct intel_uc_fw *uc_fw, bool *old_ver)
 {
        struct intel_gt *gt = __uc_fw_to_gt(uc_fw);
        struct intel_uc_fw_file *wanted = &uc_fw->file_wanted;
        struct intel_uc_fw_file *selected = &uc_fw->file_selected;
+       int ret;
+
+       /*
+        * MTL has some compatibility issues with early GuC/HuC binaries
+        * not working with newer ones. This is specific to MTL and we
+        * don't expect it to extend to other platforms.
+        */
+       if (IS_METEORLAKE(gt->i915) && uc_fw->type == INTEL_UC_FW_TYPE_HUC) {
+               ret = check_mtl_huc_guc_compatibility(gt, selected);
+               if (ret)
+                       return ret;
+       }
 
        if (!wanted->ver.major || !selected->ver.major)
                return 0;