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 AF249C433FE for ; Wed, 12 Jan 2022 10:27:31 +0000 (UTC) Received: from localhost ([::1]:53598 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1n7aqo-0006MJ-Mk for qemu-devel@archiver.kernel.org; Wed, 12 Jan 2022 05:27:30 -0500 Received: from eggs.gnu.org ([209.51.188.92]:42370) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1n7ao6-0003bL-Cx for qemu-devel@nongnu.org; Wed, 12 Jan 2022 05:24:43 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:54443) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1n7ao4-0002Fb-Eg for qemu-devel@nongnu.org; Wed, 12 Jan 2022 05:24:41 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1641983080; 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=X/wBvKdQrqtutFpt9mLnacu4tuCBJM2RMB16LyOgZio=; b=TudOmtjd5fb6Y7YSQjD/E3O/v2CZt/xTpL5BaJvsIrnY9+LK+IffcyxteP96iABbb7R8kj S8JmE1BTWw1doimUmqK5N8l1wB5rFOFD3WOS9bQoEz8OXw8bm0VtWKjDiDxFCyNGRV5alI 4cRXIqK4XaW4AZyWBQB0Oqn0flseYrg= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-339-F9B3P8XCPRSBzoQ42LfIRg-1; Wed, 12 Jan 2022 05:24:38 -0500 X-MC-Unique: F9B3P8XCPRSBzoQ42LfIRg-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 7B43381EE60; Wed, 12 Jan 2022 10:24:37 +0000 (UTC) Received: from redhat.com (unknown [10.33.36.138]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 09C6C1059110; Wed, 12 Jan 2022 10:24:35 +0000 (UTC) Date: Wed, 12 Jan 2022 10:24:33 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Peter Maydell Subject: Re: [PATCH] sgx: Move sgx object from /machine/unattached to /machine Message-ID: References: <20220112165517.4140482-1-yang.zhong@intel.com> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/2.1.3 (2021-09-10) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=berrange@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit 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: -33 X-Spam_score: -3.4 X-Spam_bar: --- X-Spam_report: (-3.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.595, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 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?= Cc: Yang Zhong , eduardo@habkost.net, qemu-devel@nongnu.org, pbonzini@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, Jan 12, 2022 at 10:16:33AM +0000, Peter Maydell wrote: > On Wed, 12 Jan 2022 at 10:14, Daniel P. Berrangé wrote: > > > > On Wed, Jan 12, 2022 at 11:55:17AM -0500, Yang Zhong wrote: > > > When Libvirt start, it get the vcpu's unavailable-features from > > > /machine/unattached/device[0] path by qom-get command, but in SGX > > > guest, since the sgx-epc virtual device is initialized before VCPU > > > creation(virtual sgx need set the virtual EPC info in the cpuid). This > > > /machine/unattached/device[0] is occupied by sgx-epc device, which > > > fail to get the unvailable-features from /machine/unattached/device[0]. > > > > If libvirt decides to enable SGX in a VM, then surely it knows > > that it should just query /machine/unattached/device[1] to get > > the CPU features instead. Why do we need to do anything in QEMU ? > > libvirt having to know it needs to look at /machine/unattached/device[n] > for anything is a bit fragile, really... it's effectively encoding > knowledge about what order things happen to get created inside QEMU. So how do CPUs and other devices end up being under /unattached/ ? Can we ensure that *all* QEMU devices have a well defined attachment point ? 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 :|