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envelope-from=pasic@linux.ibm.com; helo=mx0b-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, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=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: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Mon, 26 Jan 2026 19:40:09 +0300 Vladimir Sementsov-Ogievskiy wrote: > >> +/** > >> + * virtio_queue_set_guest_notifier - set/unset queue or config guest > >> + * notifier > >> + * > >> + * @vdev: the VirtIO device > >> + * @n: queue number, or VIRTIO_CONFIG_IRQ_IDX to set config notifer > > > > Semantically are mixing queue numbers and interrupt indexes here. > > That's preexisting logic in virtio_pci_set_guest_notifier_fd_handler(). > > But, you are right, that's doesn't answer the question, is it good to share > the logic with mmio and ccw. > > Is config notifier only pci specific, or similar feature may appear in future > for mmio and/or ccw? AFAIR there is no notifier for ccw. A possible explanation for that is, that AFAIK that config space notifications (device -> driver) are always classic I/O interrupts while queue indicators can be so called adapter I/O interrupts and irqfd is only available for adapter I/O interrupts. If you like you can have a look at "4.3.2.6 Setting Up Indicators" in https://docs.oasis-open.org/virtio/virtio/v1.3/csd01/virtio-v1.3-csd01.html#x1-1940003 I see no reason why virtio_config_guest_notifier_read() based, i.e !irqfd virtio config notifier should not exist or would not work. And I guess it is needed for certain vhost things. But nevertheless, I can't find the place where a virtio-ccw config notifier is set up. Eric, what is your opinion on this? My current thinking is that virtio-ccw not having a config notifier is basically a bug. Regards, Halil