From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41865) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1c6iQt-0002yH-8J for qemu-devel@nongnu.org; Tue, 15 Nov 2016 13:26:11 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1c6iQq-0004fo-57 for qemu-devel@nongnu.org; Tue, 15 Nov 2016 13:26:11 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:34887) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1c6iQp-0004fU-TT for qemu-devel@nongnu.org; Tue, 15 Nov 2016 13:26:08 -0500 Received: from pps.filterd (m0098399.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id uAFIOgVr108495 for ; Tue, 15 Nov 2016 13:26:06 -0500 Received: from e06smtp07.uk.ibm.com (e06smtp07.uk.ibm.com [195.75.94.103]) by mx0a-001b2d01.pphosted.com with ESMTP id 26r1yxhfkb-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Tue, 15 Nov 2016 13:26:05 -0500 Received: from localhost by e06smtp07.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 15 Nov 2016 18:26:03 -0000 Received: from b06cxnps4075.portsmouth.uk.ibm.com (d06relay12.portsmouth.uk.ibm.com [9.149.109.197]) by d06dlp02.portsmouth.uk.ibm.com (Postfix) with ESMTP id 13B4D2190023 for ; Tue, 15 Nov 2016 18:25:14 +0000 (GMT) Received: from d06av01.portsmouth.uk.ibm.com (d06av01.portsmouth.uk.ibm.com [9.149.37.212]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id uAFIQ0OM26345520 for ; Tue, 15 Nov 2016 18:26:00 GMT Received: from d06av01.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av01.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id uAFIPxOb032002 for ; Tue, 15 Nov 2016 11:26:00 -0700 From: Claudio Imbrenda Date: Tue, 15 Nov 2016 19:25:59 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Message-Id: Subject: [Qemu-devel] a small issue with VSOCK List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Hajnoczi Cc: "Michael S. Tsirkin" , Christoffer Dall , =?UTF-8?Q?Alex_Benn=c3=a9e?= , marius vlad , Greg Kurz , Ian Campbell , qemu-devel@nongnu.org Hello, I have found a small issue in the current implementation of VSOCK: if you load both the vhost_vsock module (or if it's compiled in) then the vmw_vsock_virtio_transport will not load successfully (both when compiled as a module or compiled in). The actual error message I get is: vmw_vsock_virtio_transport: probe of virtio2 failed with error -16 I dug into the code and it seems that vsock_core_init is called twice, once for the vhost module and once for the virtio-transport module, the second time returning -EBUSY (-16) since it's already initialized. This means that if a guest loads the vhost_vsock module, or if it is compiled in, then the guest can't use virtio-vsock. This also prevents using vsock in a nested virtualization scenario, where both host and guest modules could work at the same time. Unfortunately I don't have the time to fix this, I just wanted to raise the issue here, so that you are now aware of it, and can maybe fix it in the future. best regards, Claudio Imbrenda