From nobody Tue Sep 23 22:08:29 2025 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1752745835815739.3085648837488; Thu, 17 Jul 2025 02:50:35 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ucLFI-0001AE-PO; Thu, 17 Jul 2025 05:49:53 -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 1ucL2P-0003pq-69; Thu, 17 Jul 2025 05:36:26 -0400 Received: from isrv.corpit.ru ([212.248.84.144]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ucL2N-00029h-2i; Thu, 17 Jul 2025 05:36:24 -0400 Received: from tsrv.corpit.ru (tsrv.tls.msk.ru [192.168.177.2]) by isrv.corpit.ru (Postfix) with ESMTP id EF5F6137D02; Thu, 17 Jul 2025 12:34:05 +0300 (MSK) Received: from think4mjt.origo (mjtthink.wg.tls.msk.ru [192.168.177.146]) by tsrv.corpit.ru (Postfix) with ESMTP id D230E2491FB; Thu, 17 Jul 2025 12:34:13 +0300 (MSK) From: Michael Tokarev To: qemu-devel@nongnu.org Cc: qemu-stable@nongnu.org, Zhao Liu , Babu Moger , Paolo Bonzini , Michael Tokarev Subject: [Stable-10.0.3 65/65] i386/cpu: Honor maximum value for CPUID.8000001DH.EAX[25:14] Date: Thu, 17 Jul 2025 12:34:01 +0300 Message-ID: <20250717093412.728292-26-mjt@tls.msk.ru> X-Mailer: git-send-email 2.47.2 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=212.248.84.144; envelope-from=mjt@tls.msk.ru; helo=isrv.corpit.ru X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, 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: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZM-MESSAGEID: 1752745836756116600 Content-Type: text/plain; charset="utf-8" From: Zhao Liu CPUID.8000001DH:EAX[25:14] is "NumSharingCache", and the number of logical processors sharing this cache is the value of this field incremented by 1. Because of its width limitation, the maximum value currently supported is 4095. Though at present Q35 supports up to 4096 CPUs, by constructing a specific topology, the width of the APIC ID can be extended beyond 12 bits. For example, using `-smp threads=3D33,cores=3D9,modules=3D9` results = in a die level offset of 6 + 4 + 4 =3D 14 bits, which can also cause overflow. Check and honor the maximum value as CPUID.04H did. Cc: Babu Moger Signed-off-by: Zhao Liu Link: https://lore.kernel.org/r/20250714080859.1960104-8-zhao1.liu@intel.com Signed-off-by: Paolo Bonzini (cherry picked from commit 5d21ee453ad8e3f95f75e542cb3b35c5bb7cf23a) Signed-off-by: Michael Tokarev diff --git a/target/i386/cpu.c b/target/i386/cpu.c index 0480ad4ab1..b768d8ea33 100644 --- a/target/i386/cpu.c +++ b/target/i386/cpu.c @@ -496,7 +496,8 @@ static void encode_cache_cpuid8000001d(CPUCacheInfo *ca= che, =20 *eax =3D CACHE_TYPE(cache->type) | CACHE_LEVEL(cache->level) | (cache->self_init ? CACHE_SELF_INIT_LEVEL : 0); - *eax |=3D max_thread_ids_for_cache(topo_info, cache->share_level) << 1= 4; + /* Bits 25:14 - NumSharingCache: maximum 4095. */ + *eax |=3D MIN(max_thread_ids_for_cache(topo_info, cache->share_level),= 4095) << 14; =20 assert(cache->line_size > 0); assert(cache->partitions > 0); --=20 2.47.2