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Tsirkin" , virtio-fs@redhat.com, Eugenio =?utf-8?Q?P=C3=A9rez?= , Anton Kuchin , Yajun Wu , qemu-devel@nongnu.org Subject: Re: [Virtio-fs] (no subject) Date: Fri, 06 Oct 2023 16:17:34 +0100 In-reply-to: Message-ID: <87il7jg4oe.fsf@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=2a00:1450:4864:20::330; envelope-from=alex.bennee@linaro.org; helo=mail-wm1-x330.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-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: 2.1.29 Precedence: list List-Id: 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 Hanna Czenczek writes: > On 06.10.23 12:34, Michael S. Tsirkin wrote: >> On Fri, Oct 06, 2023 at 11:47:55AM +0200, Hanna Czenczek wrote: >>> On 06.10.23 11:26, Michael S. Tsirkin wrote: >>>> On Fri, Oct 06, 2023 at 11:15:55AM +0200, Hanna Czenczek wrote: >>>>> On 06.10.23 10:45, Michael S. Tsirkin wrote: >>>>>> On Fri, Oct 06, 2023 at 09:48:14AM +0200, Hanna Czenczek wrote: >>>>>>> On 05.10.23 19:15, Michael S. Tsirkin wrote: >>>>>>>> On Thu, Oct 05, 2023 at 01:08:52PM -0400, Stefan Hajnoczi wrote: >>>>>>>>> On Wed, Oct 04, 2023 at 02:58:57PM +0200, Hanna Czenczek wrote: >>> What I=E2=80=99m saying is, 923b8921d21 introduced SET_STATUS calls tha= t broke all >>> devices that would implement them as per virtio spec, and even today it= =E2=80=99s >>> broken for stateful devices.=C2=A0 The mentioned performance issue is l= ikely >>> real, but we can=E2=80=99t address it by making up SET_STATUS calls tha= t are wrong. >>> >>> I concede that I didn=E2=80=99t think about DRIVER_OK.=C2=A0 Personally= , I would do all >>> final configuration that would happen upon a DRIVER_OK once the first v= ring >>> is started (i.e. receives a kick).=C2=A0 That has the added benefit of = being >>> asynchronous because it doesn=E2=80=99t block any vhost-user messages (= which are >>> synchronous, and thus block downtime). >>> >>> Hanna >> >> For better or worse kick is per ring. It's out of spec to start rings >> that were not kicked but I guess you could do configuration ... >> Seems somewhat asymmetrical though. > > I meant to take the first ring being started as the signal to do the > global configuration, i.e. not do this once per vring, but once > globally. > >> Let's wait until next week, hopefully Yajun Wu will answer. > > I mean, personally I don=E2=80=99t really care about the whole SET_STATUS > thing.=C2=A0 It=E2=80=99s clear that it=E2=80=99s broken for stateful dev= ices.=C2=A0 The fact > that it took until 6f8be29ec17d to fix it for just any device that > would implement it according to spec to me is a strong indication that > nobody does implement it according to spec, and is currently only used > to signal to some specific back-end that all rings have been set up > and should be configured in a single block. I'm certainly using [GS]ET_STATUS for the proposed F_TRANSPORT extensions where everything is off-loaded to the vhost-user backend. --=20 Alex Benn=C3=A9e Virtualisation Tech Lead @ Linaro