From nobody Sat Oct 25 08:49:10 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1518637409693843.4910523528947; Wed, 14 Feb 2018 11:43:29 -0800 (PST) Received: from localhost ([::1]:53319 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1em2xk-0004wp-MC for importer@patchew.org; Wed, 14 Feb 2018 14:43:28 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52285) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1em2vQ-0003Wt-DV for qemu-devel@nongnu.org; Wed, 14 Feb 2018 14:41:05 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1em2vL-00033Z-Us for qemu-devel@nongnu.org; Wed, 14 Feb 2018 14:41:04 -0500 Received: from 6.mo179.mail-out.ovh.net ([46.105.56.76]:37798) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1em2vL-00032g-Ne for qemu-devel@nongnu.org; Wed, 14 Feb 2018 14:40:59 -0500 Received: from player168.ha.ovh.net (b7.ovh.net [213.186.33.57]) by mo179.mail-out.ovh.net (Postfix) with ESMTP id 33249A3A06 for ; Wed, 14 Feb 2018 20:40:58 +0100 (CET) Received: from bahia.lan (lns-bzn-46-82-253-208-248.adsl.proxad.net [82.253.208.248]) (Authenticated sender: groug@kaod.org) by player168.ha.ovh.net (Postfix) with ESMTPA id F2BCE42007E; Wed, 14 Feb 2018 20:40:53 +0100 (CET) From: Greg Kurz To: qemu-devel@nongnu.org Date: Wed, 14 Feb 2018 20:40:53 +0100 Message-ID: <151863725388.3003.620735626834741475.stgit@bahia.lan> In-Reply-To: <151863720814.3003.4939908778788942974.stgit@bahia.lan> References: <151863720814.3003.4939908778788942974.stgit@bahia.lan> User-Agent: StGit/0.17.1-46-g6855-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Ovh-Tracer-Id: 10433151490729548070 X-VR-SPAMSTATE: OK X-VR-SPAMSCORE: -100 X-VR-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgedtfedrfedtgdduvdekucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuqfggjfdpvefjgfevmfevgfenuceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddm X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 46.105.56.76 Subject: [Qemu-devel] [PATCH 4/5] spapr: consolidate the VCPU id numbering logic in a single place X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Laurent Vivier , qemu-ppc@nongnu.org, Sam Bobroff , David Gibson Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Several places in the code need to calculate a VCPU id: (cpu_index / smp_threads) * spapr->vsmt + cpu_index % smp_threads (core_id / smp_threads) * spapr->vsmt (1 user) index * spapr->vsmt (2 users) or guess that the VCPU id of a given VCPU is the first thread of a virtual core: index % spapr->vsmt !=3D 0 Even if the numbering logic isn't that complex, it is rather fragile to have these assumptions open-coded in several places. FWIW this was proved with recent issues related to VSMT. This patch moves the VCPU id formula to a single function to be called everywhere the code needs to compute one. It also adds an helper to guess if a VCPU is the first thread of a VCORE. Signed-off-by: Greg Kurz --- hw/ppc/spapr.c | 29 ++++++++++++++++++++++------- 1 file changed, 22 insertions(+), 7 deletions(-) diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c index 18ebc058acdd..800d3f001253 100644 --- a/hw/ppc/spapr.c +++ b/hw/ppc/spapr.c @@ -99,6 +99,20 @@ =20 #define PHANDLE_XICP 0x00001111 =20 +/* These two functions implement the VCPU id numbering: one to compute them + * all and one to identify thread 0 of a VCORE. Any change to the first one + * is likely to have an impact on the second one, so let's keep them close. + */ +static int spapr_vcpu_id(sPAPRMachineState *spapr, int cpu_index) +{ + return + (cpu_index / smp_threads) * spapr->vsmt + cpu_index % smp_threads; +} +static bool spapr_is_vcore(sPAPRMachineState *spapr, PowerPCCPU *cpu) +{ + return spapr_get_vcpu_id(cpu) % spapr->vsmt =3D=3D 0; +} + static ICSState *spapr_ics_create(sPAPRMachineState *spapr, const char *type_ics, int nr_irqs, Error **errp) @@ -345,7 +359,7 @@ static int spapr_fixup_cpu_dt(void *fdt, sPAPRMachineSt= ate *spapr) int index =3D spapr_get_vcpu_id(cpu); int compat_smt =3D MIN(smp_threads, ppc_compat_max_vthreads(cpu)); =20 - if (index % spapr->vsmt !=3D 0) { + if (!spapr_is_vcore(spapr, cpu)) { continue; } =20 @@ -630,7 +644,7 @@ static void spapr_populate_cpus_dt_node(void *fdt, sPAP= RMachineState *spapr) DeviceClass *dc =3D DEVICE_GET_CLASS(cs); int offset; =20 - if (index % spapr->vsmt !=3D 0) { + if (!spapr_is_vcore(spapr, cpu)) { continue; } =20 @@ -2251,7 +2265,7 @@ static void spapr_init_cpus(sPAPRMachineState *spapr) =20 if (mc->has_hotpluggable_cpus) { spapr_dr_connector_new(OBJECT(spapr), TYPE_SPAPR_DRC_CPU, - (core_id / smp_threads) * spapr->vsmt); + spapr_vcpu_id(spapr, core_id)); } =20 if (i < boot_cores_nr) { @@ -3293,7 +3307,8 @@ void spapr_core_unplug_request(HotplugHandler *hotplu= g_dev, DeviceState *dev, return; } =20 - drc =3D spapr_drc_by_id(TYPE_SPAPR_DRC_CPU, index * spapr->vsmt); + drc =3D spapr_drc_by_id(TYPE_SPAPR_DRC_CPU, + spapr_vcpu_id(spapr, cc->core_id)); g_assert(drc); =20 spapr_drc_detach(drc); @@ -3322,7 +3337,8 @@ static void spapr_core_plug(HotplugHandler *hotplug_d= ev, DeviceState *dev, cc->core_id); return; } - drc =3D spapr_drc_by_id(TYPE_SPAPR_DRC_CPU, index * spapr->vsmt); + drc =3D spapr_drc_by_id(TYPE_SPAPR_DRC_CPU, + spapr_vcpu_id(spapr, cc->core_id)); =20 g_assert(drc || !mc->has_hotpluggable_cpus); =20 @@ -3807,8 +3823,7 @@ void spapr_set_vcpu_id(PowerPCCPU *cpu, int cpu_index= , Error **errp) sPAPRMachineState *spapr =3D SPAPR_MACHINE(qdev_get_machine()); int vcpu_id; =20 - vcpu_id =3D - (cpu_index / smp_threads) * spapr->vsmt + cpu_index % smp_threads; + vcpu_id =3D spapr_vcpu_id(spapr, cpu_index); =20 if (kvm_enabled() && !kvm_vcpu_id_is_valid(vcpu_id)) { error_setg(errp, "Can't create CPU with id %d in KVM", vcpu_id);