From mboxrd@z Thu Jan 1 00:00:00 1970 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 491B7CEF172 for ; Tue, 8 Oct 2024 13:22:17 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1syAA0-0000S3-FZ; Tue, 08 Oct 2024 09:21:56 -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 1syA9y-0000Rg-1F for qemu-devel@nongnu.org; Tue, 08 Oct 2024 09:21:54 -0400 Received: from mail-pj1-x1029.google.com ([2607:f8b0:4864:20::1029]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1syA9v-0006zY-9H for qemu-devel@nongnu.org; Tue, 08 Oct 2024 09:21:53 -0400 Received: by mail-pj1-x1029.google.com with SMTP id 98e67ed59e1d1-2e0d9b70455so4318994a91.3 for ; Tue, 08 Oct 2024 06:21:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1728393706; x=1728998506; darn=nongnu.org; h=content-transfer-encoding:in-reply-to:from:references:cc:to:subject :user-agent:mime-version:date:message-id:from:to:cc:subject:date :message-id:reply-to; bh=AbX1unSQ2Vs088oDBVPkZC/yDHJZsiarhjCxYs2wQoI=; b=YPhBcL1L2wjHe7BCA3ARDPQzv+/1IuqBy8lJ03xguUBnfVHS253XxAv/zHmVH7NyV0 bAt3dSQzpXxjRQuRyWlfR2Jtfy+q4+Uc002TGDHvweL0Qq4MhaRXSh68Ayq9Z6W2F1jL AT10hcZnsMcxr5cyq29UmJi4rI4+/081wkQd5ZXbeuUt3m+80USoMn3VjPx98/yCEkuX EfCqDY1KLjflBXxCIeQTfOh+w0Rihk+vETkcoHrLX/3DbMeFU2vBD0mZBsq0Qgflj9mE jyI9AtA/FVw/xuxvH6Dj3FwRTmuqTbDHgmWF6h81IBp+z4HQpHGDthp6JF+s40PZk0pY vEoA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1728393706; x=1728998506; h=content-transfer-encoding:in-reply-to:from:references:cc:to:subject :user-agent:mime-version:date:message-id:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=AbX1unSQ2Vs088oDBVPkZC/yDHJZsiarhjCxYs2wQoI=; b=pOsv4e9zn1jyEVQtyIc9kcd4TXsCshn3C/YkxQ9tt3mfUhoHBujnX2MJhuMg1kl89r w8WiNTxhsdoJjCv6BKed9s4ABYLj5I3JGjtQhnQOkVjCGHQw8aO7cGNJFKe6NfQsJI1U R8Ow/5RKEHAGhyfpMrhiPeZHdwAWwwiaZLAUG5niCvDzdd1hJWkoz3tz/RirvMn7mm/i 9HzlFa1elea4SZM235vO7ZQslyWjV1D4j1ywCz2sDEwrpEAqsOvuBukpibnoBJVueykD 0Zmc15fLcvCdaXnVIyV/IiGWHa0Ik/5Nn/7U8OPUSDulzcEoCmvOkmb0WPWy9KLWY/wA /Wsg== X-Gm-Message-State: AOJu0YxHOHMX7cgIWgc3EJnB2A/k1O0xSY705PlKIdhszmAJBIVBtuPz VFPtdBI/3risV20Uls9M6/TiEEuhaPwRBbY+kD1s/ltxqtpG0gfI+q3dWwFu4ao= X-Google-Smtp-Source: AGHT+IGuZLNdCvfacOtsHnp4NUyIVN9kt2nFsvvICCHqQ++zF+p4Q2qJcz2OTiuSvekbydEmVhFsvQ== X-Received: by 2002:a17:90b:4b12:b0:2e0:b65b:6b4d with SMTP id 98e67ed59e1d1-2e1e63b4286mr14501643a91.41.1728393706447; Tue, 08 Oct 2024 06:21:46 -0700 (PDT) Received: from [10.84.144.194] ([203.208.167.151]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2e1e83cab87sm9435653a91.5.2024.10.08.06.21.42 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 08 Oct 2024 06:21:46 -0700 (PDT) Message-ID: <2bc89f23-9162-4668-b3a9-066c30df8e13@bytedance.com> Date: Tue, 8 Oct 2024 21:21:41 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4] i386/cpu: fixup number of addressable IDs for logical processors in the physical package To: Zhao Liu Cc: qemu-devel@nongnu.org, pbonzini@redhat.com, imammedo@redhat.com, xieyongji@bytedance.com, chaiwen.cc@bytedance.com, qemu-stable@nongnu.org, Guixiong Wei , Yipeng Yin References: <20241007081344.10907-1-xuchuangxclwt@bytedance.com> From: Chuang Xu In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=2607:f8b0:4864:20::1029; envelope-from=xuchuangxclwt@bytedance.com; helo=mail-pj1-x1029.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 Hi Zhao. On 10/8/24 上午10:55, Zhao Liu wrote: > Hi Chuang. > > Look fine for me, and only some minor nits: > > On Mon, Oct 07, 2024 at 04:13:44PM +0800, Chuang Xu wrote: >> Date: Mon, 7 Oct 2024 16:13:44 +0800 >> From: Chuang Xu >> Subject: [PATCH v4] i386/cpu: fixup number of addressable IDs for logical >> processors in the physical package >> X-Mailer: git-send-email 2.24.3 (Apple Git-128) >> >> 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 >> >> Try to execute "cpuid -1 -l 1 -r" in guest, we'll obtain a value of 90 for >> CPUID.01H.EBX[23:16], while the expected value is 128. And Try to >> execute "cpuid -1 -l 4 -r" in guest, we'll obtain a value of 63 for >> CPUID.04H.EAX[31:26] as expected. > I polished the sentences a bit: > > 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]) round up to the nearest power-of-2 integer, > s/round/rounds/ > >> 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, > What's xtopology? What I want to express here is Extended Topology Enumeration Leaf. >> 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 theads-per-core should actually be 2. > s/theads-per-core/threads-per-core/ > >> So let us round up CPUID.01H.EBX[23:16] to the nearest power-of-2 integer >> to solve the unexpected result. >> >> In addition, we introduce max_thread_number_in_package() instead of >> using pow2ceil() to be compatible with smp and hybrid. >> >> Signed-off-by: Guixiong Wei >> Signed-off-by: Yipeng Yin >> Signed-off-by: Chuang Xu >> --- >> target/i386/cpu.c | 8 +++++++- >> 1 file changed, 7 insertions(+), 1 deletion(-) >> >> diff --git a/target/i386/cpu.c b/target/i386/cpu.c >> index 85ef7452c0..1b4e3b6931 100644 >> --- a/target/i386/cpu.c >> +++ b/target/i386/cpu.c >> @@ -261,6 +261,12 @@ static uint32_t max_thread_ids_for_cache(X86CPUTopoInfo *topo_info, >> return num_ids - 1; >> } >> >> +static uint32_t max_thread_number_in_package(X86CPUTopoInfo *topo_info) >> +{ >> + uint32_t num_threads = 1 << apicid_pkg_offset(topo_info); >> + return num_threads; >> +} >> + >> static uint32_t max_core_ids_in_package(X86CPUTopoInfo *topo_info) >> { >> uint32_t num_cores = 1 << (apicid_pkg_offset(topo_info) - >> @@ -6462,7 +6468,7 @@ 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; >> + *ebx |= max_thread_number_in_package(&topo_info) << 16; > This helper has only 1 caller and its name doesn't distinguish the > addressable ID, so it's not necessary. I feel it's better to shift > the bits directly here: > > *ebx |= 1 << apicid_pkg_offset(topo_info) << 16; > >> *edx |= CPUID_HT; >> } >> if (!cpu->enable_pmu) { >> -- >> 2.20.1 >> > Reviewed-by: Zhao Liu Thanks, Later I'll send patch v5.