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Tsirkin" To: David Hildenbrand Cc: Daniel Verkamp , Halil Pasic , linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, virtualization@lists.linux.dev, kvm@vger.kernel.org, Chandra Merla , Stable@vger.kernel.org, Cornelia Huck , Thomas Huth , Eric Farman , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Wei Wang Subject: Re: [PATCH v1] s390/virtio_ccw: don't allocate/assign airqs for non-existing queues Message-ID: <20250407170239-mutt-send-email-mst@kernel.org> References: <20250407042058-mutt-send-email-mst@kernel.org> <0c221abf-de20-4ce3-917d-0375c1ec9140@redhat.com> <20250407044743-mutt-send-email-mst@kernel.org> <20250407045456-mutt-send-email-mst@kernel.org> <33def1b0-d9d5-46f1-9b61-b0269753ecce@redhat.com> <88d8f2d2-7b8a-458f-8fc4-c31964996817@redhat.com> <3bbad51d-d7d8-46f7-a28c-11cc3af6ef76@redhat.com> Precedence: bulk X-Mailing-List: virtualization@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <3bbad51d-d7d8-46f7-a28c-11cc3af6ef76@redhat.com> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: eDmAD6bROYSe7LJxzA7tZI9tVZXrNCR8LNRIKKdt95M_1744060810 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Mon, Apr 07, 2025 at 08:47:05PM +0200, David Hildenbrand wrote: > > In my opinion, it makes the most sense to keep the spec as it is and > > change QEMU and the kernel to match, but obviously that's not trivial > > to do in a way that doesn't break existing devices and drivers. > > If only it would be limited to QEMU and Linux ... :) > > Out of curiosity, assuming we'd make the spec match the current QEMU/Linux > implementation at least for the 3 involved features only, would there be a > way to adjust crossvm without any disruption? > > I still have the feeling that it will be rather hard to get that all > implementations match the spec ... For new features+queues it will be easy > to force the usage of fixed virtqueue numbers, but for free-page-hinting and > reporting, it's a mess :( Still thinking about a way to fix drivers... We can discuss this theoretically, maybe? -- MST