From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50856) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cBexe-0002KC-06 for qemu-devel@nongnu.org; Tue, 29 Nov 2016 04:44:31 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cBexY-0003b3-OH for qemu-devel@nongnu.org; Tue, 29 Nov 2016 04:44:24 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:44017 helo=mx0a-001b2d01.pphosted.com) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cBexY-0003a8-Hn for qemu-devel@nongnu.org; Tue, 29 Nov 2016 04:44:20 -0500 Received: from pps.filterd (m0098416.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id uAT9iBI2040534 for ; Tue, 29 Nov 2016 04:44:18 -0500 Received: from e06smtp13.uk.ibm.com (e06smtp13.uk.ibm.com [195.75.94.109]) by mx0b-001b2d01.pphosted.com with ESMTP id 2711590j0s-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Tue, 29 Nov 2016 04:44:18 -0500 Received: from localhost by e06smtp13.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 29 Nov 2016 09:44:15 -0000 Date: Tue, 29 Nov 2016 10:44:06 +0100 From: Cornelia Huck In-Reply-To: <33183CC9F5247A488A2544077AF19020DA14A53D@DGGEMA505-MBX.china.huawei.com> References: <1480334903-6672-1-git-send-email-arei.gonglei@huawei.com> <1480334903-6672-2-git-send-email-arei.gonglei@huawei.com> <20161128141244.4defcfa1.cornelia.huck@de.ibm.com> <33183CC9F5247A488A2544077AF19020DA14A53D@DGGEMA505-MBX.china.huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Message-Id: <20161129104406.6c110ae0.cornelia.huck@de.ibm.com> Subject: Re: [Qemu-devel] [virtio-dev] Re: [PATCH v3] crypto: add virtio-crypto driver List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Gonglei (Arei)" Cc: "linux-kernel@vger.kernel.org" , "qemu-devel@nongnu.org" , "virtio-dev@lists.oasis-open.org" , "virtualization@lists.linux-foundation.org" , "linux-crypto@vger.kernel.org" , Luonengjun , "mst@redhat.com" , "stefanha@redhat.com" , "Huangweidong (C)" , "Wubin (H)" , "xin.zeng@intel.com" , Claudio Fontana , "herbert@gondor.apana.org.au" , "pasic@linux.vnet.ibm.com" , "davem@davemloft.net" , "Zhoujian (jay, Euler)" , "Hanweidong (Randy)" , "arei.gonglei@hotmail.com" , "Xuquan (Quan Xu)" , longpeng , "salvatore.benedetto@intel.com" On Tue, 29 Nov 2016 01:37:44 +0000 "Gonglei (Arei)" wrote: > > On Mon, 28 Nov 2016 20:08:23 +0800 > > Gonglei wrote: > > > > > +static int virtcrypto_update_status(struct virtio_crypto *vcrypto) > > > +{ > > > + u32 status; > > > + int err; > > > + > > > + virtio_cread(vcrypto->vdev, > > > + struct virtio_crypto_config, status, &status); > > > + > > > + /* Ignore unknown (future) status bits */ > > > + status &= VIRTIO_CRYPTO_S_HW_READY; > > > > I'm wondering what the driver really should do if it encounters unknown > > status bits. > > > > I'd expect that new status bits are guarded by a feature bit and that > > the device should not set status bits if the respective feature bit has > > not been negotiated. Therefore, unknown status bits would be a host > > error and the driver should consider the device to be broken. > > > > Thoughts? > > > I agree with you. > > The reasonable way is reset the device if the driver > receive an unknown status IMO. What about setting FAILED in the generic virtio status? This indicates to the host that the driver 'has given up on the device', as the spec puts it. If the driver simply resets it, chances are that we will end up in the same situation again (after all, that's a host bug). Or/additionally use virtio_break_device(), as a quick grep revealed that qemu, for one, does not do anything with FAILED. That way at least the driver will stop mucking with the device.