From patchwork Thu Feb 24 15:24:14 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?b?SsO8cmdlbiBHcm/Dnw==?= X-Patchwork-Id: 12758742 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8D09FC433EF for ; Thu, 24 Feb 2022 15:24:31 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.278411.475642 (Exim 4.92) (envelope-from ) id 1nNFyc-00022N-Ey; Thu, 24 Feb 2022 15:24:18 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 278411.475642; Thu, 24 Feb 2022 15:24:18 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1nNFyc-00022G-C4; Thu, 24 Feb 2022 15:24:18 +0000 Received: by outflank-mailman (input) for mailman id 278411; Thu, 24 Feb 2022 15:24:17 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1nNFyb-0001zs-Gk for xen-devel@lists.xenproject.org; Thu, 24 Feb 2022 15:24:17 +0000 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id d41fd7f9-9585-11ec-8539-5f4723681683; Thu, 24 Feb 2022 16:24:16 +0100 (CET) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 3CE5021634; Thu, 24 Feb 2022 15:24:16 +0000 (UTC) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 016E613AFF; Thu, 24 Feb 2022 15:24:15 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id j9QPOh+jF2LzXAAAMHmgww (envelope-from ); Thu, 24 Feb 2022 15:24:15 +0000 X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: d41fd7f9-9585-11ec-8539-5f4723681683 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1645716256; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=CMUX6zu06GtcQAZGr8gKrme0g9ECkJiXojjlwJeMzfg=; b=uy+k4qRi50QdZ5Z+iHf8EnFwcBfaF1+pZebYjYK8D3ChuTiWmxmw9+LAbtl+AXQe0YYv4u S4ZP0CG/9eZJW6T8dwffnDjKDkFc1B90UQDAelRyMVv31DqcNaZDUmJTDifokRpI7yhIAP 915Ko18NwsfHUcC1+2uIz5FCKEvzXio= From: Juergen Gross To: xen-devel@lists.xenproject.org Cc: Juergen Gross , Andrew Cooper , George Dunlap , Jan Beulich , Julien Grall , Stefano Stabellini , Wei Liu Subject: [PATCH v3] xen/public: add comment to struct xen_mem_acquire_resource Date: Thu, 24 Feb 2022 16:24:14 +0100 Message-Id: <20220224152414.27948-1-jgross@suse.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Commit 7c7f7e8fba01 changed xen/include/public/memory.h in an incompatible way. Unfortunately the changed parts were already in use in the Linux kernel, so an update of the header in the kernel would result in a build breakage. As the change of above commit was in a section originally meant to be not stable, it was the usage in the kernel which was wrong. Add a comment to the modified struct for not reusing the now removed bit, in order to avoid kernels using it stumbling over a possible new meaning of the bit. In case the kernel is updating to a new version of the header, the wrong use case must be removed first. Signed-off-by: Juergen Gross Acked-by: Jan Beulich --- V2: - only add comment instead of reverting commit 7c7f7e8fba01 (Jan Beulich) V3: - make pad field comment more specific --- xen/include/public/memory.h | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/xen/include/public/memory.h b/xen/include/public/memory.h index 383a9468c3..2d0817eab1 100644 --- a/xen/include/public/memory.h +++ b/xen/include/public/memory.h @@ -662,6 +662,13 @@ struct xen_mem_acquire_resource { * two calls. */ uint32_t nr_frames; + /* + * Padding field, must be zero on input. + * In a previous version this was an output field with the lowest + * bit named XENMEM_rsrc_acq_caller_owned. Future versions of this + * interface will not reuse this bit with the field being zero on + * input. + */ uint32_t pad; /* * IN - the index of the initial frame to be mapped. This parameter