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References: <20210713153758.323614-1-andrew@daynix.com> <20210713153758.323614-6-andrew@daynix.com> <87y29dct4m.fsf@dusky.pond.sub.org> Date: Tue, 24 Aug 2021 08:41:34 +0200 In-Reply-To: (Andrew Melnichenko's message of "Tue, 10 Aug 2021 14:58:41 +0300") Message-ID: <877dgbpco1.fsf@dusky.pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=armbru@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain Received-SPF: pass client-ip=170.10.133.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.743, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Daniel P. =?utf-8?Q?Berrang=C3=A9?=" , "Michael S. Tsirkin" , Jason Wang , qemu-devel@nongnu.org, Yuri Benditovich , Yan Vugenfirer , Eric Blake Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Andrew Melnichenko writes: > Hi, > >> The helper may or may not be installed at the path compiled into QEMU. >> > Yes, so the helper will not be called - QEMU will try to initiate eBPF RSS > or use "in-qemu" RSS. My point is: the proposed command's mission is to help the management application run the right helper. However, its advice is *unreliable*. It may point to the wrong helper, or to nothing at all. The right helper may still exist elsewhere. I suspect you're trying to address the problem at the wrong level. Similar versioning issues exist with other helpers. We've been doing fine without QEMU providing unreliable advice on where they might sit in the file system. What makes this one different? >> What happens when you use the wrong helper? >> > UB - in most cases, eBPF program will work with wrong configurations. > That's why the stamp was added. > > query-helper-paths checks the stamp only for RSS helper. I have no idea what you're talking about :) My best guess is that you're trying to tell me that attempting to work with the wrong helper will fail cleanly due to some stamp check. That would be nice.