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Mon, 22 Mar 2021 13:12:50 +0000 (GMT) Received: from li-e979b1cc-23ba-11b2-a85c-dfd230f6cf82 (unknown [9.171.57.111]) by d06av25.portsmouth.uk.ibm.com (Postfix) with SMTP; Mon, 22 Mar 2021 13:12:50 +0000 (GMT) Date: Mon, 22 Mar 2021 14:12:48 +0100 From: Halil Pasic To: Gerd Hoffmann Subject: Re: [PATCH 0/3] s390x: modularize virtio-gpu-ccw Message-ID: <20210322141248.031f7538.pasic@linux.ibm.com> In-Reply-To: <20210317095622.2839895-1-kraxel@redhat.com> References: <20210317095622.2839895-1-kraxel@redhat.com> Organization: IBM X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.32; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.369, 18.0.761 definitions=2021-03-22_07:2021-03-22, 2021-03-22 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 mlxlogscore=999 lowpriorityscore=0 clxscore=1015 priorityscore=1501 phishscore=0 spamscore=0 adultscore=0 malwarescore=0 suspectscore=0 mlxscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2103220093 Received-SPF: pass client-ip=148.163.158.5; envelope-from=pasic@linux.ibm.com; helo=mx0a-001b2d01.pphosted.com X-Spam_score_int: -19 X-Spam_score: -2.0 X-Spam_bar: -- X-Spam_report: (-2.0 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, 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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Thomas Huth , David Hildenbrand , Cornelia Huck , Richard Henderson , qemu-devel@nongnu.org, Christian Borntraeger , qemu-s390x@nongnu.org, "Michael S. Tsirkin" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, 17 Mar 2021 10:56:19 +0100 Gerd Hoffmann wrote: > Maybe not the most elegant but rather simple approach to the "parent > object missing" problem: Use a symbol reference to make sure ccw modules > load only in case ccw support is present. [..] Hi Gerd! I've tested this and I think mostly does what it should. The only thing that I'm inclined to consider a little quirky is the first message: $ ./qemu-system-x86_64 -device virtio-gpu-ccw Failed to open module: /home/pasic/build/qemu/hw-s390x-virtio-gpu-ccw.so: undefined symbol: have_virtio_ccw qemu-system-x86_64: -device virtio-gpu-ccw: 'virtio-gpu-ccw' is not a valid device model name But with something like --help we don't see it, and I assume neither do we when probing, because there the modules are loaded with mayfail. So for me this is acceptable, because it happens only if one tries to use a device that ain't advertised. Compared to Daniels suggestion, I find that one conceptually clearer, and even more flexible. Implementation-wise I find this patch-set simpler. I don't know how would it scale to modules depending on modules (and it feels a little hackish), but we can address such problems as they emerge if they emerge, so I did not think too hard. Let me also note, that you took authorship of all three patches, which I'm fine with. All I really care about at this stage is getting this fixed in a remotely sane way, and this is definitely one. I'm also willing to invest more work in that symlink based approach, if that is what the community wants, but I would prefer this fixed as soon as possible. If you keep the authorship for all the patches, I would like to offer: Reviewed-by: Halil Pasic Tested-by: Halil Pasic for all three patches. (If I'm going to be the author of some of the patches, those tags don't make sense for those). Thanks for your work! Regards, Halil