From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lists1p.gnu.org (lists1p.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BCE0D606A31E for ; Fri, 23 Oct 2026 10:21:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=P3WBgI2j Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1xKCOS-0000od-Gz; Fri, 23 Oct 2026 06:21:00 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1xKCOR-0000oT-71 for qemu-devel@nongnu.org; Fri, 23 Oct 2026 06:20:59 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1xKCOP-0004aP-6S for qemu-devel@nongnu.org; Fri, 23 Oct 2026 06:20:58 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1792750855; 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=UMBFXq+G0YQMy58Yz/izyom/SBj/bU1W9hVaC0yfuMQ=; b=P3WBgI2jAyEu+lTiCwwOItql6wV7LbE6J1I7t83lFPkVkKx0G96nWdnrxx9EiKZIIpOHaW ufyqX8yoMg5N0YGBUpmby5icTz89DCsmv6NwKmdnqsCy8+5NaaT5oZXbnjnZOQpXnVXBk0 8TjqOawJy6FciRwAPgWEeouqYuFfS0s= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-692-6YkwwYFkOAmMYb3Wne4G_g-1; Fri, 23 Oct 2026 06:20:51 -0400 X-MC-Unique: 6YkwwYFkOAmMYb3Wne4G_g-1 X-Mimecast-MFC-AGG-ID: 6YkwwYFkOAmMYb3Wne4G_g_1792750851 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id C629D180059B; Fri, 23 Oct 2026 10:20:50 +0000 (UTC) Received: from redhat.com (headnet04.pony-001.prod.iad2.dc.redhat.com [10.2.32.116]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 972F6195608C; Fri, 23 Oct 2026 10:20:48 +0000 (UTC) Date: Fri, 23 Oct 2026 11:20:45 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Markus Armbruster Cc: qemu-devel@nongnu.org, David Hildenbrand , Igor Mammedov , Paolo Bonzini , Marcelo Tosatti , "Michael S. Tsirkin" , Richard Henderson Subject: Re: qemu-system-x86_64 appears to have sgx-epc, but not memory-backend-epc Message-ID: References: <87zew5j3iv.fsf@pond.sub.org> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <87zew5j3iv.fsf@pond.sub.org> User-Agent: Mutt/2.4.2 (2026-08-30) X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.339, 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_PASS=-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: qemu development List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org X-Spam-Status: No, score=-7.6 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_PASS,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Thu, Oct 22, 2026 at 02:58:16PM +0200, Markus Armbruster wrote: > My build of qemu-system-x86_64 has device sgx-epc: > > --> {"execute": "qom-list-types", "arguments": {"implements": "sgx-epc"}} > <-- {"return": [{"name": "sgx-epc", "parent": "device"}]} > > The device as a link property to a memory-backend-epc: > > --> {"execute": "qom-list-properties", "arguments": {"typename": "sgx-epc"}} > <-- {"return": [... > {"name": "memdev", "type": "link"}, > ...]} > > However, type memory-backend-epc does not exist: > > --> {"execute": "qom-list-types", "arguments": {"implements": "memory-backend"}} > <-- {"return": [{"name": "memory-backend-ram", "parent": "memory-backend"}, {"name": "memory-backend-file", "parent": "memory-backend"}, {"name": "memory-backend-memfd", "parent": "memory-backend"}, {"name": "memory-backend-shm", "parent": "memory-backend"}]} There is some rather dubious code that conditionally registers the type static void register_types(void) { int fd = qemu_open_old("/dev/sgx_vepc", O_RDWR); if (fd >= 0) { close(fd); type_register_static(&sgx_epc_backed_info); } } Normal practice is for types to be unconditionally registered. Do we have any examples outside of this SGX case where we conditionally register types ? Should we change this to follow normal practice ? With regards, Daniel -- |: https://berrange.com ~~ https://hachyderm.io/@berrange :| |: https://libvirt.org ~~ https://entangle-photo.org :| |: https://pixelfed.art/berrange ~~ https://fstop138.berrange.com :|