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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B032FC433F5 for ; Thu, 11 Nov 2021 14:44:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9756961213 for ; Thu, 11 Nov 2021 14:44:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233770AbhKKOrb (ORCPT ); Thu, 11 Nov 2021 09:47:31 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:39985 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233722AbhKKOr3 (ORCPT ); Thu, 11 Nov 2021 09:47:29 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1636641880; h=from:from: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=9h35ss/MZV4b7BsVK6YSJJk8fuPoOjbqo9hy449dhgU=; b=Uz6yzdfzswbrabN4FXGSttdkKJ/Jy8KXg7AwP+h6lfT5yPl1g3H4tqJ84rB5SprioqVc/0 kQ8uYbdDex78tftbjFPUic9ayr6zdwT+ptFaQvbcpjEXVPycxuOxPtmTCWmBh2IRzqK8x7 lg8/H+2+NroiHHHXDBaeL/pK9vfvy/U= Received: from mail-ed1-f69.google.com (mail-ed1-f69.google.com [209.85.208.69]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-83-RKX4T0HCNLi-BlS4ksV1yw-1; Thu, 11 Nov 2021 09:44:39 -0500 X-MC-Unique: RKX4T0HCNLi-BlS4ksV1yw-1 Received: by mail-ed1-f69.google.com with SMTP id x13-20020a05640226cd00b003e2bf805a02so5539557edd.23 for ; Thu, 11 Nov 2021 06:44:38 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:in-reply-to:references:date :message-id:mime-version; bh=9h35ss/MZV4b7BsVK6YSJJk8fuPoOjbqo9hy449dhgU=; b=q6aSsrjA6Ubth+YJpjfjsS/B77z2O7aqHiu6GIFS1x0sLV3p1Oj8nm22ZPncF8rbAB Plbqkdp/hjxT45bj+Ap85VG2wrMCHCxb1GbWtNSPc1BoiQIDcZpBbyCdGZ0P0hwA30QA YWJhhda10U3VAl4xGOf7tbSutTAfkrrLknzG2u72d9oIc2zlDqvfgH+/gZsmpwKOtwNJ H6XGhbwIzZr0u4XVBf5D+LIksCmc29ALVqkE9xkWho5yY+p5oaUWdRqUdotVz9ifYNAy rtBN1En096n0J9UPZ3vU+HhdKw1plephoMrFiIEuJrZegca2wizeXfOn+bATIFbpNtns bXIQ== X-Gm-Message-State: AOAM532d0O9K4nSvXm0L+Jpw8W4CKMA5NydfEcZ92ipScp1zf971FFBs mnKibciKoJFWO7gHbWXRXGdP1AQPrFzubPr/jyViEdoeMPG3Pc7oSNL04ccTPsdGPa/U+br2fzB Iq26nUntEorKfMq+hfM0c8wkj0v9tYCJ0K2XZEEmnPh2VZuHpB5RgiQ8JX2DmhSOefh91NbKKCn uF X-Received: by 2002:a05:6402:524b:: with SMTP id t11mr10875870edd.98.1636641877923; Thu, 11 Nov 2021 06:44:37 -0800 (PST) X-Google-Smtp-Source: ABdhPJymshSnBa02uZ+mhC68CkdDPxQgbf+jB00yvDwjrbLe9OLRw94VZDtbrVjyAffqcbZU9xGRQA== X-Received: by 2002:a05:6402:524b:: with SMTP id t11mr10875844edd.98.1636641877764; Thu, 11 Nov 2021 06:44:37 -0800 (PST) Received: from fedora (g-server-2.ign.cz. [91.219.240.2]) by smtp.gmail.com with ESMTPSA id m9sm1420991eje.102.2021.11.11.06.44.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 11 Nov 2021 06:44:37 -0800 (PST) From: Vitaly Kuznetsov To: Sean Christopherson , Paolo Bonzini Cc: kvm@vger.kernel.org, Wanpeng Li , Jim Mattson , Eduardo Habkost , linux-kernel@vger.kernel.org Subject: Re: [PATCH RFC] KVM: x86: Drop arbitraty KVM_SOFT_MAX_VCPUS In-Reply-To: References: <20211111134733.86601-1-vkuznets@redhat.com> <5cdb6982-d4ec-118e-2534-9498196d11b8@redhat.com> Date: Thu, 11 Nov 2021 15:44:36 +0100 Message-ID: <87bl2qg3aj.fsf@redhat.com> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Sean Christopherson writes: > On Thu, Nov 11, 2021, Paolo Bonzini wrote: >> On 11/11/21 14:47, Vitaly Kuznetsov wrote: >> > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c >> > index ac83d873d65b..91ef1b872b90 100644 >> > --- a/arch/x86/kvm/x86.c >> > +++ b/arch/x86/kvm/x86.c >> > @@ -4137,7 +4137,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) >> > r = !static_call(kvm_x86_cpu_has_accelerated_tpr)(); >> > break; >> > case KVM_CAP_NR_VCPUS: >> > - r = KVM_SOFT_MAX_VCPUS; >> > + r = num_online_cpus(); > > I doubt it matters much in practice, but this really should be > > r = min(num_online_cpus(), KVM_MAX_VCPUS); > Nice catch, actually! It makes no sense to recommend > KVM_MAX_VCPUS. We should fix this across all arches though, I'll take that as an action item. -- Vitaly