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{ "id": 2185054, "url": "http://patchwork.ozlabs.org/api/covers/2185054/?format=api", "web_url": "http://patchwork.ozlabs.org/project/glibc/cover/20260116074425.1208705-1-xiejiamei@hygon.cn/", "project": { "id": 41, "url": "http://patchwork.ozlabs.org/api/projects/41/?format=api", "name": "GNU C Library", "link_name": "glibc", "list_id": "libc-alpha.sourceware.org", "list_email": "libc-alpha@sourceware.org", "web_url": "", "scm_url": "", "webscm_url": "", "list_archive_url": "", "list_archive_url_format": "", "commit_url_format": "" }, "msgid": "<20260116074425.1208705-1-xiejiamei@hygon.cn>", "list_archive_url": null, "date": "2026-01-16T07:44:24", "name": "[v2,0/1] x86: Fix for cache computation on Hygon", "submitter": { "id": 91872, "url": "http://patchwork.ozlabs.org/api/people/91872/?format=api", "name": "Jiamei Xie", "email": "xiejiamei@hygon.cn" }, "mbox": "http://patchwork.ozlabs.org/project/glibc/cover/20260116074425.1208705-1-xiejiamei@hygon.cn/mbox/", "series": [ { "id": 488578, "url": "http://patchwork.ozlabs.org/api/series/488578/?format=api", "web_url": "http://patchwork.ozlabs.org/project/glibc/list/?series=488578", "date": "2026-01-16T07:44:24", "name": "x86: Fix for cache computation on Hygon", "version": 2, "mbox": "http://patchwork.ozlabs.org/series/488578/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/covers/2185054/comments/", "headers": { "Return-Path": "<libc-alpha-bounces~incoming=patchwork.ozlabs.org@sourceware.org>", "X-Original-To": [ "incoming@patchwork.ozlabs.org", "libc-alpha@sourceware.org" ], "Delivered-To": [ "patchwork-incoming@legolas.ozlabs.org", "libc-alpha@sourceware.org" ], "Authentication-Results": [ "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=sourceware.org\n (client-ip=2620:52:6:3111::32; helo=vm01.sourceware.org;\n envelope-from=libc-alpha-bounces~incoming=patchwork.ozlabs.org@sourceware.org;\n receiver=patchwork.ozlabs.org)", "sourceware.org;\n dmarc=pass (p=none dis=none) header.from=hygon.cn", "sourceware.org; spf=pass smtp.mailfrom=hygon.cn", "server2.sourceware.org;\n arc=none smtp.remote-ip=101.204.27.37" ], "Received": [ "from vm01.sourceware.org (vm01.sourceware.org\n [IPv6:2620:52:6:3111::32])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange x25519 server-signature ECDSA (secp384r1) server-digest SHA384)\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4dssNn6qHcz1xsq\n\tfor <incoming@patchwork.ozlabs.org>; Fri, 16 Jan 2026 18:46:17 +1100 (AEDT)", "from vm01.sourceware.org (localhost [127.0.0.1])\n\tby sourceware.org (Postfix) with ESMTP id A469F4BA2E22\n\tfor <incoming@patchwork.ozlabs.org>; Fri, 16 Jan 2026 07:46:15 +0000 (GMT)", "from mailgw1.hygon.cn (unknown [101.204.27.37])\n by sourceware.org (Postfix) with ESMTP id 249924BA2E1C\n for <libc-alpha@sourceware.org>; Fri, 16 Jan 2026 07:45:26 +0000 (GMT)", "from maildlp1.hygon.cn (unknown [127.0.0.1])\n by mailgw1.hygon.cn (Postfix) with ESMTP id 4dssMk5bwbztyQd\n for <libc-alpha@sourceware.org>; Fri, 16 Jan 2026 15:45:22 +0800 (CST)", "from maildlp1.hygon.cn (unknown [172.23.18.60])\n by mailgw1.hygon.cn (Postfix) with ESMTP id 4dssMh3zFNztyQd\n for <libc-alpha@sourceware.org>; Fri, 16 Jan 2026 15:45:20 +0800 (CST)", "from cncheex04.Hygon.cn (unknown [172.23.18.114])\n by maildlp1.hygon.cn (Postfix) with ESMTPS id BA08F1558\n for <libc-alpha@sourceware.org>; Fri, 16 Jan 2026 15:45:12 +0800 (CST)", "from jianyong.hygon.cn (172.19.20.52) by cncheex04.Hygon.cn\n (172.23.18.114) with Microsoft SMTP Server (version=TLS1_2,\n cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.36; Fri, 16 Jan\n 2026 15:45:20 +0800" ], "DKIM-Filter": [ "OpenDKIM Filter v2.11.0 sourceware.org A469F4BA2E22", "OpenDKIM Filter v2.11.0 sourceware.org 249924BA2E1C" ], "DMARC-Filter": "OpenDMARC Filter v1.4.2 sourceware.org 249924BA2E1C", "ARC-Filter": "OpenARC Filter v1.0.0 sourceware.org 249924BA2E1C", "ARC-Seal": "i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1768549526; cv=none;\n b=GUHoG8OWcwU5tcl2DLKMsnW4nPzNxa+pzEvaD/6Ms+751DC/gkdhCi5hJagjRwMgdaiJT9dAxHNR/TGX0ykTyMTAupTWKz4BCOFdQWf3fBQ3kqEu+ejBPKKioo+FvijCIwgYpCDQNFAc1zb/hD/DUEUpwchOh3zH1MknC8X977Y=", "ARC-Message-Signature": "i=1; a=rsa-sha256; d=sourceware.org; s=key;\n t=1768549526; c=relaxed/simple;\n bh=4v8sY1IGmheq1sUpE29/7T+bSRLe6JlxmVkFhzX/1jk=;\n h=From:To:Subject:Date:Message-ID:MIME-Version;\n b=p1EWc5wpLN3eL8YMGq2mRtfT+dfCQmMLcT5HIr16Q81dbYsqrKBisTznTbnZ5apf7uQOU0l9B6fk3LFMQRh90Ozhhe98Ty3DPmApQSytOcyj2dU6BhKRYA6cw0D2hBTu08I3t38A8u74qQwg1YjXb4Rp4BuCMdfz87F9/hrXXmU=", "ARC-Authentication-Results": "i=1; server2.sourceware.org", "From": "Jiamei Xie <xiejiamei@hygon.cn>", "To": "<libc-alpha@sourceware.org>", "CC": "<lijing@hygon.cn>, Jiamei Xie <xiejiamei@hygon.cn>", "Subject": "[PATCH v2 0/1] x86: Fix for cache computation on Hygon", "Date": "Fri, 16 Jan 2026 15:44:24 +0800", "Message-ID": "<20260116074425.1208705-1-xiejiamei@hygon.cn>", "X-Mailer": "git-send-email 2.43.0", "MIME-Version": "1.0", "Content-Transfer-Encoding": "8bit", "Content-Type": "text/plain", "X-Originating-IP": "[172.19.20.52]", "X-ClientProxiedBy": "cncheex05.Hygon.cn (172.23.18.115) To cncheex04.Hygon.cn\n (172.23.18.114)", "X-BeenThere": "libc-alpha@sourceware.org", "X-Mailman-Version": "2.1.30", "Precedence": "list", "List-Id": "Libc-alpha mailing list <libc-alpha.sourceware.org>", "List-Unsubscribe": "<https://sourceware.org/mailman/options/libc-alpha>,\n <mailto:libc-alpha-request@sourceware.org?subject=unsubscribe>", "List-Archive": "<https://sourceware.org/pipermail/libc-alpha/>", "List-Post": "<mailto:libc-alpha@sourceware.org>", "List-Help": "<mailto:libc-alpha-request@sourceware.org?subject=help>", "List-Subscribe": "<https://sourceware.org/mailman/listinfo/libc-alpha>,\n <mailto:libc-alpha-request@sourceware.org?subject=subscribe>", "Errors-To": "libc-alpha-bounces~incoming=patchwork.ozlabs.org@sourceware.org" }, "content": "This patch series fixes incorrect cache parameter computation on\nHygon CPUs when running under certain hypervisors.\n\nGlibc currently relies on CPUID leaf 0x8000001D to compute cache\ninformation on Hygon. This works correctly on bare-metal systems.\nHowever, under some hypervisors (for example, QEMU with -cpu\nqemu64), the maximum supported extended CPUID leaf is only\n0x8000000A, and 0x8000001D is not exposed. As a result, glibc\ncomputes zeroed cache parameters, which can affect cache-aware\noptimizations.\n\nThis patch introduces a legacy fallback based on CPUID leaves\n0x80000005 and 0x80000006, consistent with the existing AMD path,\nto restore correct cache information when 0x8000001D is unavailable.\n\nThe change has been tested on Hygon systems under QEMU and\nbare-metal environments.\n\nChanges in v2:\n* Define variables 'fn' and 'l3_cache_per_ccx' at point of use.\n \nJiamei Xie (1):\n x86: Fix for cache computation on Hygon under hypervisors\n\n sysdeps/x86/dl-cacheinfo.h | 201 +++++++++++++++++++++++++++++++++----\n 1 file changed, 179 insertions(+), 22 deletions(-)" }