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 663ABC433EF for ; Mon, 9 May 2022 12:28:38 +0000 (UTC) Received: from localhost ([::1]:52182 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1no2VB-0007gR-CM for qemu-devel@archiver.kernel.org; Mon, 09 May 2022 08:28:37 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:51536) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1no27B-0004DQ-Q1 for qemu-devel@nongnu.org; Mon, 09 May 2022 08:03:51 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:32447) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1no278-0002BJ-PC for qemu-devel@nongnu.org; Mon, 09 May 2022 08:03:49 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1652097825; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references; bh=/ihLIToyatuHFlHvaJBnYPVX2EO1F64sgyrrNMmR4GU=; b=YNZfEWJDrc9FoQAX+Cm53SoTTWevCFBmNbspbnUA0IK65xRFaxBusmANi/jdIpm0gbM2Us 8wapmYK0WUBWDyFBSwCengR1AqZOcL4b9mOQ7RPIhrZWWm1w2Xd2Tokeq4dLfMrvjq6ohQ RZyd9Q06gPggABbA9/TyIiOfhmPRWNs= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-297-Umg1Y6GNM_aK2MvVMHAJVA-1; Mon, 09 May 2022 08:03:42 -0400 X-MC-Unique: Umg1Y6GNM_aK2MvVMHAJVA-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 1E1F5382ECCA; Mon, 9 May 2022 12:03:42 +0000 (UTC) Received: from redhat.com (unknown [10.33.36.145]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A3F7840D296C; Mon, 9 May 2022 12:03:40 +0000 (UTC) Date: Mon, 9 May 2022 13:03:38 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Igor Mammedov Cc: Suravee Suthikulpanit , qemu-devel@nongnu.org, marcel.apfelbaum@gmail.com, mst@redhat.com, pbonzini@redhat.com, richard.henderson@linaro.org, eduardo@habkost.net, jon.grimm@amd.com Subject: Re: [PATCH] pc: q35: Bump max_cpus to 512 Message-ID: References: <20220504131639.13570-1-suravee.suthikulpanit@amd.com> <20220509091249.392fdab6@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20220509091249.392fdab6@redhat.com> User-Agent: Mutt/2.1.5 (2021-12-30) X-Scanned-By: MIMEDefang 2.84 on 10.11.54.2 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 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: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Mon, May 09, 2022 at 09:12:49AM +0200, Igor Mammedov wrote: > On Wed, 4 May 2022 08:16:39 -0500 > Suravee Suthikulpanit wrote: > > > This is the maximum number of vCPU supported by > > the AMD x2APIC virtualization. > > > > Signed-off-by: Suravee Suthikulpanit > > --- > > hw/i386/pc_q35.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/hw/i386/pc_q35.c b/hw/i386/pc_q35.c > > index 302288342a..e82b1c690d 100644 > > --- a/hw/i386/pc_q35.c > > +++ b/hw/i386/pc_q35.c > > @@ -357,7 +357,7 @@ static void pc_q35_machine_options(MachineClass *m) > > machine_class_allow_dynamic_sysbus_dev(m, TYPE_INTEL_IOMMU_DEVICE); > > machine_class_allow_dynamic_sysbus_dev(m, TYPE_RAMFB_DEVICE); > > machine_class_allow_dynamic_sysbus_dev(m, TYPE_VMBUS_BRIDGE); > > - m->max_cpus = 288; > > + m->max_cpus = 512; > > Maybe we should bump it to KVM VCPU maximum, > and make sure we error out if asked for combination of > hardware/irqchip is not usable. In RHEL downstream we currently bump this to 710 CPUs, because you overflow the SMBIOS 2.1 tables at approx 720 CPUs (give/take a little depending on other config options). Going beyond 710 CPUs value requires using the SMBIOS 3 entry point. AFAIK, the x86 machine types still default to SMBIOS 2.1, so that would need changing too. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|