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GET /api/patches/2219745/?format=api
{ "id": 2219745, "url": "http://patchwork.ozlabs.org/api/patches/2219745/?format=api", "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20260404061215.505913-1-deller@kernel.org/", "project": { "id": 14, "url": "http://patchwork.ozlabs.org/api/projects/14/?format=api", "name": "QEMU Development", "link_name": "qemu-devel", "list_id": "qemu-devel.nongnu.org", "list_email": "qemu-devel@nongnu.org", "web_url": "", "scm_url": "", "webscm_url": "", "list_archive_url": "", "list_archive_url_format": "", "commit_url_format": "" }, "msgid": "<20260404061215.505913-1-deller@kernel.org>", "list_archive_url": null, "date": "2026-04-04T06:12:15", "name": "[v2] Allow building qemu tools on 32-bit hosts", "commit_ref": null, "pull_url": null, "state": "new", "archived": false, "hash": "13b24a41b2d193934d0e9b64ca218679809fede8", "submitter": { "id": 87076, "url": "http://patchwork.ozlabs.org/api/people/87076/?format=api", "name": "Helge Deller", "email": "deller@kernel.org" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20260404061215.505913-1-deller@kernel.org/mbox/", "series": [ { "id": 498698, "url": "http://patchwork.ozlabs.org/api/series/498698/?format=api", "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/list/?series=498698", "date": "2026-04-04T06:12:15", "name": "[v2] Allow building qemu tools on 32-bit hosts", "version": 2, "mbox": "http://patchwork.ozlabs.org/series/498698/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/2219745/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/2219745/checks/", "tags": {}, "related": [], "headers": { "Return-Path": "<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>", "X-Original-To": "incoming@patchwork.ozlabs.org", "Delivered-To": "patchwork-incoming@legolas.ozlabs.org", "Authentication-Results": [ "legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256\n header.s=k20201202 header.b=tnuu/Yhg;\n\tdkim-atps=neutral", "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; helo=lists.gnu.org;\n envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n receiver=patchwork.ozlabs.org)" ], "Received": [ "from lists.gnu.org (lists.gnu.org [209.51.188.17])\n\t(using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4fnljq3Dn9z1yCs\n\tfor <incoming@patchwork.ozlabs.org>; Sat, 04 Apr 2026 17:17:03 +1100 (AEDT)", "from localhost ([::1] helo=lists1p.gnu.org)\n\tby lists.gnu.org with esmtp (Exim 4.90_1)\n\t(envelope-from <qemu-devel-bounces@nongnu.org>)\n\tid 1w8uIx-0004ca-Cy; Sat, 04 Apr 2026 02:16:23 -0400", "from eggs.gnu.org ([2001:470:142:3::10])\n by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256)\n (Exim 4.90_1) (envelope-from <deller@kernel.org>) id 1w8uFP-0008J9-LE\n for qemu-devel@nongnu.org; Sat, 04 Apr 2026 02:12:46 -0400", "from sea.source.kernel.org ([172.234.252.31])\n by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256)\n (Exim 4.90_1) (envelope-from <deller@kernel.org>) id 1w8uFN-0006IQ-2k\n for qemu-devel@nongnu.org; Sat, 04 Apr 2026 02:12:42 -0400", "from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58])\n by sea.source.kernel.org (Postfix) with ESMTP id 9573444218;\n Sat, 4 Apr 2026 06:12:30 +0000 (UTC)", "by smtp.kernel.org (Postfix) with ESMTPSA id 6D424C19423;\n Sat, 4 Apr 2026 06:12:29 +0000 (UTC)" ], "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org;\n s=k20201202; t=1775283150;\n bh=Qu1MmIA319sagiWUVovBMOJREzMLGa8fh5BgQBpLZLI=;\n h=From:To:Cc:Subject:Date:From;\n b=tnuu/YhgBLYwlsaCBVLlHBUiwK4TbomUoS8iLeqsJJK9v+oGpfPYznhra9F/jxYjT\n 8/CbA5hOX6RIDlk3BzztvnZNNojMQ1Nw9ViKyFiO4W9KDxFwcSSFtOmdkPVrq5/YrO\n Nowe6JmJiVTIv9IjCCD83KIKjppnn1zsi/2udTXTCCxGJW/IcXwI6d2UX3l8elct6T\n GeuiQbc/4afl7FEWFU+aNgIi/A3IKBkpxF2jZ/Qy5uSFtb2EI62ndmY3/NPhr/SNRr\n sdZiDxctaRVo3qaMjtBkF/8eUCesNcyNFL2ccBfKkFTWNEiopXrV1Wz+7ftglbJuIL\n 5xT5pIYR0RWRw==", "From": "Helge Deller <deller@kernel.org>", "To": "qemu-devel@nongnu.org", "Cc": "deller@gmx.de, Michael Tokarev <mjt@tls.msk.ru>,\n richard.henderson@linaro.org", "Subject": "[PATCH] [PATCH v2] Allow building qemu tools on 32-bit hosts", "Date": "Sat, 4 Apr 2026 08:12:15 +0200", "Message-ID": "<20260404061215.505913-1-deller@kernel.org>", "X-Mailer": "git-send-email 2.53.0", "MIME-Version": "1.0", "Content-Transfer-Encoding": "8bit", "Received-SPF": "pass client-ip=172.234.252.31; envelope-from=deller@kernel.org;\n helo=sea.source.kernel.org", "X-Spam_score_int": "-25", "X-Spam_score": "-2.6", "X-Spam_bar": "--", "X-Spam_report": "(-2.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.544,\n DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1,\n RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001,\n RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001,\n SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no", "X-Spam_action": "no action", "X-BeenThere": "qemu-devel@nongnu.org", "X-Mailman-Version": "2.1.29", "Precedence": "list", "List-Id": "qemu development <qemu-devel.nongnu.org>", "List-Unsubscribe": "<https://lists.nongnu.org/mailman/options/qemu-devel>,\n <mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>", "List-Archive": "<https://lists.nongnu.org/archive/html/qemu-devel>", "List-Post": "<mailto:qemu-devel@nongnu.org>", "List-Help": "<mailto:qemu-devel-request@nongnu.org?subject=help>", "List-Subscribe": "<https://lists.nongnu.org/mailman/listinfo/qemu-devel>,\n <mailto:qemu-devel-request@nongnu.org?subject=subscribe>", "Errors-To": "qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org", "Sender": "qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org" }, "content": "From: Helge Deller <deller@gmx.de>\n\nQemu's tools like qemu-img are often needed on 32-bit platforms,\nalthough the actual qemu emulators have been discontinued on 32-bit.\n\nTo allow building the tools on 32-bit this patch implements three small\nchanges:\n\na) The check in meson.build is changed to still error out if the user\ntries to build qemu-system or qemu-user on a 32-bit platform, but allows\nbuilding tools (e.g. by \"--enable-tools\") alone.\n\nb) The compile time check in atomic.h now checks against\nsizeof(uint64_t) so that 32-bit environments can still build\nsuccessfully, while 128-bit atomic operations are prevented to sneak in.\n\nc) Allow linking against libatomic as long as we don't build the\nqemu-system and qemu-user binaries.\n\nSucessfully tested on the 32-bit big-endian powerpc architecture.\n\nv2:\n- keep comple time checks in atomic.h\n- allow linking against libatomic when building tools\n\nSigned-off-by: Helge Deller <deller@gmx.de>\nSiggested-by: Richard Henderson <richard.henderson@linaro.org>\n---\n include/qemu/atomic.h | 6 +++---\n meson.build | 16 ++++++++++++----\n 2 files changed, 15 insertions(+), 7 deletions(-)", "diff": "diff --git a/include/qemu/atomic.h b/include/qemu/atomic.h\nindex dc9290084b..e4dd948863 100644\n--- a/include/qemu/atomic.h\n+++ b/include/qemu/atomic.h\n@@ -58,11 +58,11 @@\n \n /*\n * Sanity check that the size of an atomic operation isn't \"overly large\".\n- * Despite the fact that e.g. i686 has 64-bit atomic operations, we do not\n+ * Despite the fact that e.g. x86-64 has 128-bit atomic operations, we do not\n * want to use them because we ought not need them, and this lets us do a\n- * bit of sanity checking that other 32-bit hosts might build.\n+ * bit of sanity checking that other 32- and 64-bit hosts might build.\n */\n-#define ATOMIC_REG_SIZE sizeof(void *)\n+#define ATOMIC_REG_SIZE sizeof(uint64_t)\n \n /* Weak atomic operations prevent the compiler moving other\n * loads/stores past the atomic operation load/store. However there is\ndiff --git a/meson.build b/meson.build\nindex daa58e46a3..8b0f00608d 100644\n--- a/meson.build\n+++ b/meson.build\n@@ -323,8 +323,8 @@ endif\n # Compiler flags #\n ##################\n \n-if cc.sizeof('void *') < 8\n- error('QEMU requires a 64-bit CPU host architecture')\n+if (cc.sizeof('void *') < 8) and (have_system or have_user)\n+ error('QEMU emulator requires a 64-bit CPU host architecture. Only tools may be built for 32-bit.')\n endif\n \n foreach lang : all_languages\n@@ -423,8 +423,16 @@ endif\n #\n # Later checks assume we won't get atomic ops for int128 without\n # explicitly asking for -latomic, so we must disable GCC's new\n-# automatic linking with the new -fno-link-libatomic flag\n-qemu_isa_flags += cc.get_supported_arguments('-fno-link-libatomic')\n+# automatic linking with the new -fno-link-libatomic flag.\n+#\n+# When not building the emulators, but qemu helper tools only\n+# (e.g. on 32-bit hosts), libatomic is sometimes required and\n+# thus acceptable.\n+if (have_system or have_user)\n+ qemu_isa_flags += cc.get_supported_arguments('-fno-link-libatomic')\n+else\n+ qemu_ldflags += cc.get_supported_link_arguments('-Wl,-latomic')\n+endif\n \n qemu_common_flags = qemu_isa_flags + qemu_common_flags\n \n", "prefixes": [ "v2" ] }