platform/x86/intel/ifs: Metadata validation for start_chunk

Add an additional check to validate IFS image metadata field prior to
loading the test image.

If start_chunk is not a multiple of chunks_per_stride error out.
Signed-off-by: Jithu Joseph <jithu.joseph@intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Tested-by: Pengfei Xu <pengfei.xu@intel.com>
Link: https://lore.kernel.org/r/20231005195137.3117166-7-jithu.joseph@intel.comReviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

drivers/platform/x86/intel/ifs/load.c

@@ -291,6 +291,13 @@ static int validate_ifs_metadata(struct device *dev)
 		return ret;
 	}
 
+	if (ifs_meta->chunks_per_stride &&
+	    (ifs_meta->starting_chunk % ifs_meta->chunks_per_stride != 0)) {
+		dev_warn(dev, "Starting chunk num %u not a multiple of chunks_per_stride %u\n",
+			 ifs_meta->starting_chunk, ifs_meta->chunks_per_stride);
+		return ret;
+	}
+
 	return 0;
 }