From patchwork Wed Oct 9 03:56:38 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chuang Xu X-Patchwork-Id: 13827522 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.gnu.org (lists.gnu.org [209.51.188.17]) (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 9F411CF043B for ; Wed, 9 Oct 2024 03:57:33 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1syNoo-0007j7-Va; Tue, 08 Oct 2024 23:56:59 -0400 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 1syNon-0007il-Hb for qemu-devel@nongnu.org; Tue, 08 Oct 2024 23:56:57 -0400 Received: from mail-pl1-x62e.google.com ([2607:f8b0:4864:20::62e]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1syNol-0008Pb-1v for qemu-devel@nongnu.org; Tue, 08 Oct 2024 23:56:57 -0400 Received: by mail-pl1-x62e.google.com with SMTP id d9443c01a7336-20b90984971so65534355ad.3 for ; Tue, 08 Oct 2024 20:56:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1728446213; x=1729051013; darn=nongnu.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=zysoOgYWRxFsYfR8sAY5YlZkGoFfzyRqcIlflQhRqKQ=; b=TP8dm8eNNDOZOgCoiKIj+IJQYGXwfkHI9aj2LaPTR4yBS+RlYUJMxfkFDWB+fYxmyJ oPt20/rZWQJ2renaOCQ7LjxNnw73JEgP4WoaahNvY6Rmr324b49JKwR51pVl7VbnMfiT eg2/N+9kUfl0rq4OEBlyu8+JW2oDvKfh9bZrETFsVgzcPUSw31oiDcWcsxfUs0Uwyp5J YZB5tHvbS8W9Htm1sj6vocH9vJ9Dk8094322LmChX8ti5Zu5wGZsB17WKa2YV2FGouan CaTeb6tsV96R+DxVs68UztaUB3MeeAmF8Ojjcl2O7hQdAPTSwzqqbV/pzY6dkw7wEK2m u1mg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1728446213; x=1729051013; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=zysoOgYWRxFsYfR8sAY5YlZkGoFfzyRqcIlflQhRqKQ=; b=aILvlytVOa+USs/N2rLVd2zDzJFXKGjhQm6vGwbd54shEOpmdBFi1U5CLkpL+FE73o 0M5u6DgOVKFiwYXdmcmhCtcPA+0CJrZvZZ3jKBJ7QKncbybAhqyJnT7OBymGRdvARqJY avrdg8RcroKljqBGYzBcwNkrWMR86TrzARoOdrI5zXqbZx9iXJKWkEzqTBThQ62YVQEW Fu47obihB/yaCJX/9Ren8K3pNrw0qeGJYqymLpqTw1o9yDUj3A4a+7McG0d8Pwz+o0HZ 3DrLdk2XHoN6wXQlkbGOONZwVpp9PmZDVURrW+XlCWf4nXbfdplSAsrpytwUWqvHJv+N o7OQ== X-Gm-Message-State: AOJu0YzoqFKsR6hVJvRiwimq+twU6wvWrKRvYLsMd/GgPFsRrq1A9yoi sudNFUxsFF94Xyk8dVpibdAVgdStlcYBPnTMov3znTk5zyfz/RNcqzBgLASj78J//83R6I3IJB6 L X-Google-Smtp-Source: AGHT+IHHOAAXiK86D5kpqgvkhWQJ4mGIs4kUvfOR44j2sdswvokkRkbhranYe3I3YXGTRxdzWB7zGA== X-Received: by 2002:a17:902:d504:b0:20b:770b:ad2e with SMTP id d9443c01a7336-20c6373ce12mr17785155ad.28.1728446213234; Tue, 08 Oct 2024 20:56:53 -0700 (PDT) Received: from KK6FJ77W06.bytedance.net ([203.208.167.151]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-20c13994f84sm62417255ad.290.2024.10.08.20.56.49 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Tue, 08 Oct 2024 20:56:52 -0700 (PDT) From: Chuang Xu To: qemu-devel@nongnu.org Cc: pbonzini@redhat.com, imammedo@redhat.com, xieyongji@bytedance.com, chaiwen.cc@bytedance.com, zhao1.liu@intel.com, qemu-stable@nongnu.org, Chuang Xu , Guixiong Wei , Yipeng Yin Subject: [PATCH v6] i386/cpu: fixup number of addressable IDs for logical processors in the physical package Date: Wed, 9 Oct 2024 11:56:38 +0800 Message-Id: <20241009035638.59330-1-xuchuangxclwt@bytedance.com> X-Mailer: git-send-email 2.39.3 (Apple Git-146) MIME-Version: 1.0 Received-SPF: pass client-ip=2607:f8b0:4864:20::62e; envelope-from=xuchuangxclwt@bytedance.com; helo=mail-pl1-x62e.google.com X-Spam_score_int: -8 X-Spam_score: -0.9 X-Spam_bar: / X-Spam_report: (-0.9 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FROM_LOCAL_NOVOWEL=0.5, HK_RANDOM_ENVFROM=0.001, HK_RANDOM_FROM=0.66, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org When QEMU is started with: -cpu host,migratable=on,host-cache-info=on,l3-cache=off -smp 180,sockets=2,dies=1,cores=45,threads=2 On Intel platform: CPUID.01H.EBX[23:16] is defined as "max number of addressable IDs for logical processors in the physical package". When executing "cpuid -1 -l 1 -r" in the guest, we obtain a value of 90 for CPUID.01H.EBX[23:16], whereas the expected value is 128. Additionally, executing "cpuid -1 -l 4 -r" in the guest yields a value of 63 for CPUID.04H.EAX[31:26], which matches the expected result. As (1+CPUID.04H.EAX[31:26]) rounds up to the nearest power-of-2 integer, we'd beter round up CPUID.01H.EBX[23:16] to the nearest power-of-2 integer too. Otherwise we may encounter unexpected results in guest. For example, when QEMU is started with CLI above and xtopology is disabled, guest kernel 5.15.120 uses CPUID.01H.EBX[23:16]/(1+CPUID.04H.EAX[31:26]) to calculate threads-per-core in detect_ht(). Then guest will get "90/(1+63)=1" as the result, even though threads-per-core should actually be 2. And on AMD platform: CPUID.01H.EBX[23:16] is defined as "Logical processor count". Current result meets our expectation. So let us round up CPUID.01H.EBX[23:16] to the nearest power-of-2 integer only for Intel platform to solve the unexpected result. Reviewed-by: Zhao Liu Acked-by: Igor Mammedov Signed-off-by: Guixiong Wei Signed-off-by: Yipeng Yin Signed-off-by: Chuang Xu --- target/i386/cpu.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/target/i386/cpu.c b/target/i386/cpu.c index ff227a8c5c..641d4577b0 100644 --- a/target/i386/cpu.c +++ b/target/i386/cpu.c @@ -6462,7 +6462,15 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count, } *edx = env->features[FEAT_1_EDX]; if (threads_per_pkg > 1) { - *ebx |= threads_per_pkg << 16; + /* + * AMD requires logical processor count, but Intel needs maximum + * number of addressable IDs for logical processors per package. + */ + if (cpu->vendor_cpuid_only && IS_AMD_CPU(env)) { + *ebx |= threads_per_pkg << 16; + } else { + *ebx |= 1 << apicid_pkg_offset(&topo_info) << 16; + } *edx |= CPUID_HT; } if (!cpu->enable_pmu) {