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 58CFBC77B7A for ; Fri, 2 Jun 2023 08:45:04 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1q50OP-0006yI-Kp; Fri, 02 Jun 2023 04:44:17 -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 1q50ON-0006xr-1S for qemu-devel@nongnu.org; Fri, 02 Jun 2023 04:44:15 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1q50OK-0008WO-W7 for qemu-devel@nongnu.org; Fri, 02 Jun 2023 04:44:14 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1685695451; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=13/Fy9jdtd8VG1ggNAGISvgx+ddqOHrEsXg9kYkbumo=; b=hYETHrWjQIPessuTfEBtNUelCOv1jHV7aYDctAnQPHFJp2wv9SW94bOQ4wIfWIzv93MVgg NOQwZQ4cFMnrLQOoqt693SB3NTo5lQYSC2dTURiLK/ImnXMoGL6Uuvr7gZaiIX9+feY7NZ DPG2JsJMyRZtI682Be/lZBTrWBxku1A= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-649-iTRyMmBeM5yU8JkeIcaZkQ-1; Fri, 02 Jun 2023 04:44:06 -0400 X-MC-Unique: iTRyMmBeM5yU8JkeIcaZkQ-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 76D3F101A53A; Fri, 2 Jun 2023 08:44:05 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.158]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 6502A2166B25; Fri, 2 Jun 2023 08:43:48 +0000 (UTC) Date: Fri, 2 Jun 2023 09:43:45 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: "Suthikulpanit, Suravee" Cc: "Michael S. Tsirkin" , Joao Martins , qemu-devel@nongnu.org, pbonzini@redhat.com, richard.henderson@linaro.org, eduardo@habkost.net, marcel.apfelbaum@gmail.com, imammedo@redhat.com, jusual@redhat.com, jon.grimm@amd.com, santosh.Shukla@amd.com, Gerd Hoffmann Subject: Re: [PATCH v2] pc: q35: Bump max_cpus to 1024 Message-ID: References: <20230531225127.331998-1-suravee.suthikulpanit@amd.com> <39a49814-28d8-ffc8-42b4-3af14bb9dd47@oracle.com> <20230601070912-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/2.2.9 (2022-11-12) X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 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: -22 X-Spam_score: -2.3 X-Spam_bar: -- X-Spam_report: (-2.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.166, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, 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-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Thu, Jun 01, 2023 at 02:54:54PM -0700, Suthikulpanit, Suravee wrote: > > > On 6/1/2023 6:09 PM, Michael S. Tsirkin wrote: > > On Thu, Jun 01, 2023 at 11:17:30AM +0100, Daniel P. Berrangé wrote: > > > On Thu, Jun 01, 2023 at 11:09:45AM +0100, Joao Martins wrote: > > > > > > > > On 31/05/2023 23:51, Suravee Suthikulpanit wrote: > > > > > Since KVM_MAX_VCPUS is currently defined to 1024 for x86 as shown in > > > > > arch/x86/include/asm/kvm_host.h, update QEMU limits to the same number. > > > > > > > > > > In case KVM could not support the specified number of vcpus, QEMU would > > > > > return the following error message: > > > > > > > > > > qemu-system-x86_64: kvm_init_vcpu: kvm_get_vcpu failed (xxx): Invalid argument > > > > > > > > > > Signed-off-by: Suravee Suthikulpanit > > > > > --- > > > > > > > > > > Changes from V1: > > > > > (https://lore.kernel.org/all/YnkDGsIi1vFvXmiP@redhat.com/T/) > > > > > * Bump from 512 to KVM_MAX_VCPUS (per Igor's suggestion) > > > > > > > > > > Note: > > > > > From the last discussion, Daniel mentioned that SMBIO 2.1 tables might > > > > > cause overflow at approx 720 CPUs, and it might require using the > > > > > SMBIO 3.0 entry point. Also, we might need to change the default for > > > > > the x86 machine type to SMBIO 3.0. However, I do not know the status > > > > > of this. > > > > > > > > > I suspect smbios 3.0 (64-bit entry point) is already supported. > > > > > > > > With current qemu and all the smbios fixes in the last cycle, perhaps this is > > > > mainly just setting smbios_entry_point_type to SMBIOS_ENTRY_POINT_TYPE_64 if > > > > MachineState::smp::max_cpus is bigger than 720 (e.g. in pc_q35_init()?) > > > >> The need for the 64-bit entry point depends on a combination of > > > RAM > config > > > and CPU count. IMHO we need to unconditionally switch the latest machine > > > types to use the 64-bit entry point by default, rather than trying to infer > > > some special condition to dynamically change on the fly. > > Yes, makes sense. > > Thanks all for the feedback. So, IIUC, here is how the SMBIOS entry point > types would be affected by the QEMU options: > > - pc-q35-8.1 and later, default to SMBIOS EP type 64. > - pc-q35-8.0 and older, default to SMBIOS EP type 32. > - User can override the type w/ QEMU option "-M .., > smbios-entry-point-type=[32|64]" > > Please let me know if I am missing anything. If this is accurate, I'll send > out v3 with this change. Yes, and for pc-i440fx* 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 :|