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MID_RHS_MATCH_FROM(0.00)[] X-Rspamd-Queue-Id: BFF6F21BDC Received-SPF: pass client-ip=195.135.223.130; envelope-from=farosas@suse.de; helo=smtp-out1.suse.de 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, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 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 Peter Xu writes: > [I queued patch 1-2 into -stable, leaving this patch for further > discussions] > > On Fri, Mar 15, 2024 at 08:55:42AM +0000, Daniel P. Berrang=C3=A9 wrote: >> The 'file:' protocol eventually calls into qemu_open, and this >> transparently allows for FD passing using /dev/fdset/NNN syntax >> to pass in FDs.=20 > > If it always use /dev/fdsets for files, does it mean that the newly added > SOCKET_ADDRESS_TYPE_FD support on mapped-ram will never be used (so we can > drop them)? We already have SOCKET_ADDRESS_TYPE_FD + file since 8.2 when the MigrationAddress was added. So this: 'channels': [ { 'channel-type': 'main', 'addr': { 'transport': 'socket', 'type': 'fd', 'str': 'fdname' } } ] works without multifd and without mapped-ram if the fd is a file or socket. So yes, you're correct, but given we already have this^ it would be perhaps more confusing for users to allow it, but not allow the very same JSON when multifd=3Dtrue, mapped-ram=3Dtrue. That's the only reason I didn't propose reverting commit decdc76772 ("migration/multifd: Add mapped-ram support to fd: URI"). For mapped-ram in libvirt, we'll definitely not use SOCKET_ADDRESS_TYPE_FD (as in the JSON), because I don't think libvirt supports the new API. As for SOCKET_ADDRESS_TYPE_FD as in "fd:", we could use it when direct-io is disabled. With direct-io, the fdset will be required. > > What about the old getfd? Is it obsolete because it relies on monitor > object? Or maybe it's still in use? > > It would be greatly helpful if there can be a summary of how libvirt uses > fd for migration purpose. > > Thanks,