From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by lists.gnu.org with archive (Exim 4.90_1) id 1rcoOR-00026x-OK for mharc-qemu-trivial@gnu.org; Wed, 21 Feb 2024 10:20:19 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rcoKz-0000wC-2h; Wed, 21 Feb 2024 10:16:45 -0500 Received: from mgamail.intel.com ([198.175.65.19]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rcnvv-0006fX-6p; Wed, 21 Feb 2024 09:50:53 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1708527051; x=1740063051; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=F06opmdQj8jsmdUPOzllj+66O8Vb8X3YdS5EM/vRWJE=; b=BfMv1H19DsC6cfZ5lweun26Uo60Y5G9vqgRCf6MMtPGZ60sGoPE8XV6A cvhiGeBRYfv9AEjNwScPjc/T0NsMWn5JNI9x1AGMFjxuPUFxNXuvPrcsf b823f/HMNhaj0IY9uL2U35TnfjKBdCAPp3Epxs7T9hQe3303Lt2CZQJi7 WFaya4jEN/ytEkS3RJbUv5ow8GGTn0r8npUL6HnrhYOQrLxv36zRpHwoG Qip8oj7JzDFMPIYgHMvA9x2XJ0P1I6e3lHrHpkR76/uPda+as//NzUZ8C XCcyEWSjF+ZdGIbJpcWqxX5ErzoPbyamb9Ac4Ir4aYLIGWGn6m2yYZYmx Q==; X-IronPort-AV: E=McAfee;i="6600,9927,10990"; a="2551701" X-IronPort-AV: E=Sophos;i="6.06,175,1705392000"; d="scan'208";a="2551701" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orvoesa111.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Feb 2024 06:50:48 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10990"; a="913318118" X-IronPort-AV: E=Sophos;i="6.06,175,1705392000"; d="scan'208";a="913318118" Received: from liuzhao-optiplex-7080.sh.intel.com (HELO localhost) ([10.239.160.36]) by fmsmga002.fm.intel.com with ESMTP; 21 Feb 2024 06:50:44 -0800 Date: Wed, 21 Feb 2024 23:04:23 +0800 From: Zhao Liu To: Markus Armbruster Cc: Jonathan Cameron , Fan Ni , Laurent Vivier , Alistair Francis , "Edgar E . Iglesias" , Peter Maydell , "Michael S . Tsirkin" , Marcel Apfelbaum , Alex Williamson , =?iso-8859-1?Q?C=E9dric?= Le Goater , Philippe =?iso-8859-1?Q?Mathieu-Daud=E9?= , qemu-devel@nongnu.org, qemu-arm@nongnu.org, qemu-trivial@nongnu.org, Zhao Liu Subject: Re: [PATCH 1/6] hw/cxl/cxl-host: Fix missing ERRP_GUARD() in cxl_fixed_memory_window_config() Message-ID: References: <20240221094317.994454-1-zhao1.liu@linux.intel.com> <20240221094317.994454-2-zhao1.liu@linux.intel.com> <878r3evyth.fsf@pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <878r3evyth.fsf@pond.sub.org> Received-SPF: none client-ip=198.175.65.19; envelope-from=zhao1.liu@linux.intel.com; helo=mgamail.intel.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.05, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_NONE=0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-trivial@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 21 Feb 2024 15:17:00 -0000 On Wed, Feb 21, 2024 at 12:31:06PM +0100, Markus Armbruster wrote: > Date: Wed, 21 Feb 2024 12:31:06 +0100 > From: Markus Armbruster > Subject: Re: [PATCH 1/6] hw/cxl/cxl-host: Fix missing ERRP_GUARD() in > cxl_fixed_memory_window_config() > > Zhao Liu writes: > > > From: Zhao Liu > > > > As the comment in qapi/error, dereferencing @errp requires > > ERRP_GUARD(): > > > > * = Why, when and how to use ERRP_GUARD() = > > * > > * Without ERRP_GUARD(), use of the @errp parameter is restricted: > > * - It must not be dereferenced, because it may be null. > > * - It should not be passed to error_prepend() or > > * error_append_hint(), because that doesn't work with &error_fatal. > > * ERRP_GUARD() lifts these restrictions. > > * > > * To use ERRP_GUARD(), add it right at the beginning of the function. > > * @errp can then be used without worrying about the argument being > > * NULL or &error_fatal. > > * > > * Using it when it's not needed is safe, but please avoid cluttering > > * the source with useless code. > > > > Currently, since machine_set_cfmw() - the caller of > > cxl_fixed_memory_window_config() - doesn't get the NULL errp parameter > > as the "set" method of object property, cxl_fixed_memory_window_config() > > doesn't trigger the dereference issue. > > > > To follow the requirement of errp, add missing ERRP_GUARD() in > > cxl_fixed_memory_window_config(). > > > > Suggested-by: Markus Armbruster > > Signed-off-by: Zhao Liu > > --- > > Suggested by credit: > > Markus: Referred his explanation about ERRP_GUARD(). > > --- > > hw/cxl/cxl-host.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/hw/cxl/cxl-host.c b/hw/cxl/cxl-host.c > > index 2aa776c79c74..c5f5fcfd64d0 100644 > > --- a/hw/cxl/cxl-host.c > > +++ b/hw/cxl/cxl-host.c > > @@ -26,6 +26,7 @@ static void cxl_fixed_memory_window_config(CXLState *cxl_state, > > CXLFixedMemoryWindowOptions *object, > > Error **errp) > > { > > + ERRP_GUARD(); > > g_autofree CXLFixedWindow *fw = g_malloc0(sizeof(*fw)); > > strList *target; > > int i; > > The dereferences are > > fw->enc_int_ways = cxl_interleave_ways_enc(fw->num_targets, errp); > if (*errp) { > return; > } > > and > > fw->enc_int_gran = > cxl_interleave_granularity_enc(object->interleave_granularity, > errp); > if (*errp) { > return; > } > > We check *errp, because neither function returns a suitable error code. > > Reviewed-by: Markus Armbruster > Thanks! I'll attach your description to the commit message. Regards, Zhao