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 X-Spam-Level: X-Spam-Status: No, score=-4.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DB5FBC28E83 for ; Fri, 4 Sep 2020 07:29:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B4382206D4 for ; Fri, 4 Sep 2020 07:29:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="dnFxeIby" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729674AbgIDH3W (ORCPT ); Fri, 4 Sep 2020 03:29:22 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:24257 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728293AbgIDH3T (ORCPT ); Fri, 4 Sep 2020 03:29:19 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1599204558; 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=5WARdyX1YHYkybe8MUk7ryY2qAtsHHzu0CP+6P8E3II=; b=dnFxeIbyQOMZHm7geAey1J53M8C5whbwg7KIS0xCCtujNa/8LSC7z8wyAkMrM32884zyat ha9Gm+P27AMAyAJShyxjoi5Zo7eFOC3E8PBeZ/pmJ7XcDm//S3DysiXkVGzb/ThtArL752 6KOcSeVAhodYOHKNJBuZovuWKbj3Ifo= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-91-u6HqFIgUP1mWWoWTcIRy_Q-1; Fri, 04 Sep 2020 03:29:14 -0400 X-MC-Unique: u6HqFIgUP1mWWoWTcIRy_Q-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 72D9B56C20; Fri, 4 Sep 2020 07:29:13 +0000 (UTC) Received: from sirius.home.kraxel.org (ovpn-112-62.ams2.redhat.com [10.36.112.62]) by smtp.corp.redhat.com (Postfix) with ESMTP id 20F051A7C8; Fri, 4 Sep 2020 07:29:07 +0000 (UTC) Received: by sirius.home.kraxel.org (Postfix, from userid 1000) id D0FA731E23; Fri, 4 Sep 2020 09:29:05 +0200 (CEST) Date: Fri, 4 Sep 2020 09:29:05 +0200 From: Gerd Hoffmann To: Sean Christopherson Cc: Vitaly Kuznetsov , Peter Xu , kvm@vger.kernel.org, Paolo Bonzini , Wanpeng Li , Jim Mattson , Michael Tsirkin , Julia Suvorova , Andy Lutomirski , Andrew Jones , linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 0/3] KVM: x86: KVM_MEM_PCI_HOLE memory Message-ID: <20200904072905.vbkiq3h762fyzds6@sirius.home.kraxel.org> References: <20200807141232.402895-1-vkuznets@redhat.com> <20200825212526.GC8235@xz-x1> <87eenlwoaa.fsf@vitty.brq.redhat.com> <20200901200021.GB3053@xz-x1> <877dtcpn9z.fsf@vitty.brq.redhat.com> <20200904061210.GA22435@sjchrist-ice> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200904061210.GA22435@sjchrist-ice> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, > Unless I'm mistaken, microvm doesn't even support PCI, does it? Correct, no pci support right now. We could probably wire up ecam (arm/virt style) for pcie support, once the acpi support for mictovm finally landed (we need acpi for that because otherwise the kernel wouldn't find the pcie bus). Question is whenever there is a good reason to do so. Why would someone prefer microvm with pcie support over q35? > If all of the above is true, this can be handled by adding "pci=lastbus=0" > as a guest kernel param to override its scanning of buses. And couldn't > that be done by QEMU's microvm_fix_kernel_cmdline() to make it transparent > to the end user? microvm_fix_kernel_cmdline() is a hack, not a solution. Beside that I doubt this has much of an effect on microvm because it doesn't support pcie in the first place. take care, Gerd