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([2a01:e0a:e10:ef90:343a:68f:2e91:95c]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-38c2a17d6b2sm3546118f8f.34.2025.01.24.10.50.58 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 24 Jan 2025 10:50:58 -0800 (PST) Message-ID: Date: Fri, 24 Jan 2025 19:50:57 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] vhost-user: Implement an empty VHOST_USER_SEND_RARP command To: Stefano Brivio References: <20250124142137.2296704-1-lvivier@redhat.com> <20250124171016.322d665b@elisabeth> <5af65c6f-3bab-4852-84ac-ca8f23123b2e@redhat.com> <20250124194016.4c26375c@elisabeth> From: Laurent Vivier Autocrypt: addr=lvivier@redhat.com; keydata= xsFNBFYFJhkBEAC2me7w2+RizYOKZM+vZCx69GTewOwqzHrrHSG07MUAxJ6AY29/+HYf6EY2 WoeuLWDmXE7A3oJoIsRecD6BXHTb0OYS20lS608anr3B0xn5g0BX7es9Mw+hV/pL+63EOCVm SUVTEQwbGQN62guOKnJJJfphbbv82glIC/Ei4Ky8BwZkUuXd7d5NFJKC9/GDrbWdj75cDNQx UZ9XXbXEKY9MHX83Uy7JFoiFDMOVHn55HnncflUncO0zDzY7CxFeQFwYRbsCXOUL9yBtqLer Ky8/yjBskIlNrp0uQSt9LMoMsdSjYLYhvk1StsNPg74+s4u0Q6z45+l8RAsgLw5OLtTa+ePM JyS7OIGNYxAX6eZk1+91a6tnqfyPcMbduxyBaYXn94HUG162BeuyBkbNoIDkB7pCByed1A7q q9/FbuTDwgVGVLYthYSfTtN0Y60OgNkWCMtFwKxRaXt1WFA5ceqinN/XkgA+vf2Ch72zBkJL RBIhfOPFv5f2Hkkj0MvsUXpOWaOjatiu0fpPo6Hw14UEpywke1zN4NKubApQOlNKZZC4hu6/ 8pv2t4HRi7s0K88jQYBRPObjrN5+owtI51xMaYzvPitHQ2053LmgsOdN9EKOqZeHAYG2SmRW LOxYWKX14YkZI5j/TXfKlTpwSMvXho+efN4kgFvFmP6WT+tPnwARAQABzSNMYXVyZW50IFZp dmllciA8bHZpdmllckByZWRoYXQuY29tPsLBeAQTAQIAIgUCVgVQgAIbAwYLCQgHAwIGFQgC CQoLBBYCAwECHgECF4AACgkQ8ww4vT8vvjwpgg//fSGy0Rs/t8cPFuzoY1cex4limJQfReLr SJXCANg9NOWy/bFK5wunj+h/RCFxIFhZcyXveurkBwYikDPUrBoBRoOJY/BHK0iZo7/WQkur 6H5losVZtrotmKOGnP/lJYZ3H6OWvXzdz8LL5hb3TvGOP68K8Bn8UsIaZJoeiKhaNR0sOJyI YYbgFQPWMHfVwHD/U+/gqRhD7apVysxv5by/pKDln1I5v0cRRH6hd8M8oXgKhF2+rAOL7gvh jEHSSWKUlMjC7YwwjSZmUkL+TQyE18e2XBk85X8Da3FznrLiHZFHQ/NzETYxRjnOzD7/kOVy gKD/o7asyWQVU65mh/ECrtjfhtCBSYmIIVkopoLaVJ/kEbVJQegT2P6NgERC/31kmTF69vn8 uQyW11Hk8tyubicByL3/XVBrq4jZdJW3cePNJbTNaT0d/bjMg5zCWHbMErUib2Nellnbg6bc 2HLDe0NLVPuRZhHUHM9hO/JNnHfvgiRQDh6loNOUnm9Iw2YiVgZNnT4soUehMZ7au8PwSl4I KYE4ulJ8RRiydN7fES3IZWmOPlyskp1QMQBD/w16o+lEtY6HSFEzsK3o0vuBRBVp2WKnssVH qeeV01ZHw0bvWKjxVNOksP98eJfWLfV9l9e7s6TaAeySKRRubtJ+21PRuYAxKsaueBfUE7ZT 7zfOwU0EVgUmGQEQALxSQRbl/QOnmssVDxWhHM5TGxl7oLNJms2zmBpcmlrIsn8nNz0rRyxT 460k2niaTwowSRK8KWVDeAW6ZAaWiYjLlTunoKwvF8vP3JyWpBz0diTxL5o+xpvy/Q6YU3BN efdq8Vy3rFsxgW7mMSrI/CxJ667y8ot5DVugeS2NyHfmZlPGE0Nsy7hlebS4liisXOrN3jFz asKyUws3VXek4V65lHwB23BVzsnFMn/bw/rPliqXGcwl8CoJu8dSyrCcd1Ibs0/Inq9S9+t0 VmWiQWfQkz4rvEeTQkp/VfgZ6z98JRW7S6l6eophoWs0/ZyRfOm+QVSqRfFZdxdP2PlGeIFM C3fXJgygXJkFPyWkVElr76JTbtSHsGWbt6xUlYHKXWo+xf9WgtLeby3cfSkEchACrxDrQpj+ Jt/JFP+q997dybkyZ5IoHWuPkn7uZGBrKIHmBunTco1+cKSuRiSCYpBIXZMHCzPgVDjk4viP brV9NwRkmaOxVvye0vctJeWvJ6KA7NoAURplIGCqkCRwg0MmLrfoZnK/gRqVJ/f6adhU1oo6 z4p2/z3PemA0C0ANatgHgBb90cd16AUxpdEQmOCmdNnNJF/3Zt3inzF+NFzHoM5Vwq6rc1JP jfC3oqRLJzqAEHBDjQFlqNR3IFCIAo4SYQRBdAHBCzkM4rWyRhuVABEBAAHCwV8EGAECAAkF AlYFJhkCGwwACgkQ8ww4vT8vvjwg9w//VQrcnVg3TsjEybxDEUBm8dBmnKqcnTBFmxN5FFtI WlEuY8+YMiWRykd8Ln9RJ/98/ghABHz9TN8TRo2b6WimV64FmlVn17Ri6FgFU3xNt9TTEChq AcNg88eYryKsYpFwegGpwUlaUaaGh1m9OrTzcQy+klVfZWaVJ9Nw0keoGRGb8j4XjVpL8+2x OhXKrM1fzzb8JtAuSbuzZSQPDwQEI5CKKxp7zf76J21YeRrEW4WDznPyVcDTa+tz++q2S/Bp P4W98bXCBIuQgs2m+OflERv5c3Ojldp04/S4NEjXEYRWdiCxN7ca5iPml5gLtuvhJMSy36gl U6IW9kn30IWuSoBpTkgV7rLUEhh9Ms82VWW/h2TxL8enfx40PrfbDtWwqRID3WY8jLrjKfTd R3LW8BnUDNkG+c4FzvvGUs8AvuqxxyHbXAfDx9o/jXfPHVRmJVhSmd+hC3mcQ+4iX5bBPBPM oDqSoLt5w9GoQQ6gDVP2ZjTWqwSRMLzNr37rJjZ1pt0DCMMTbiYIUcrhX8eveCJtY7NGWNyx FCRkhxRuGcpwPmRVDwOl39MB3iTsRighiMnijkbLXiKoJ5CDVvX5yicNqYJPKh5MFXN1bvsB kmYiStMRbrD0HoY1kx5/VozBtc70OU0EB8Wrv9hZD+Ofp0T3KOr1RUHvCZoLURfFhSQ= In-Reply-To: <20250124194016.4c26375c@elisabeth> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: Me9fVRMQBp18Prvs4lTVVVY9iVBzCPsHsVi5AhMKZfc_1737744660 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Message-ID-Hash: KOTGMN5SHM2IMU7K2JUSBV2NAG4F6ZLO X-Message-ID-Hash: KOTGMN5SHM2IMU7K2JUSBV2NAG4F6ZLO X-MailFrom: lvivier@redhat.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: passt-dev@passt.top X-Mailman-Version: 3.3.8 Precedence: list List-Id: Development discussion and patches for passt Archived-At: Archived-At: List-Archive: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: On 24/01/2025 19:40, Stefano Brivio wrote: > On Fri, 24 Jan 2025 19:35:33 +0100 > Laurent Vivier wrote: > >> On 24/01/2025 17:10, Stefano Brivio wrote: >>> On Fri, 24 Jan 2025 15:21:37 +0100 >>> Laurent Vivier wrote: >>> >>>> Passt cannot manage and doesn't need to manage the broadcast of a fake RARP, >>>> but QEMU will report an error message if Passt doesn't implement it. >>>> >>>> Implement an empty SEND_RARP command to silence QEMU error message. >>>> >>>> Signed-off-by: Laurent Vivier >>>> --- >>>> vhost_user.c | 28 +++++++++++++++++++++++++++- >>>> 1 file changed, 27 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/vhost_user.c b/vhost_user.c >>>> index f12dec5ddc58..e6633ae75ce8 100644 >>>> --- a/vhost_user.c >>>> +++ b/vhost_user.c >>>> @@ -914,7 +914,8 @@ static bool vu_get_protocol_features_exec(struct vu_dev *vdev, >>>> { >>>> uint64_t features = 1ULL << VHOST_USER_PROTOCOL_F_REPLY_ACK | >>>> 1ULL << VHOST_USER_PROTOCOL_F_LOG_SHMFD | >>>> - 1ULL << VHOST_USER_PROTOCOL_F_DEVICE_STATE; >>>> + 1ULL << VHOST_USER_PROTOCOL_F_DEVICE_STATE | >>>> + 1ULL << VHOST_USER_PROTOCOL_F_RARP; >>>> >>>> (void)vdev; >>>> vmsg_set_reply_u64(msg, features); >>>> @@ -981,6 +982,30 @@ static bool vu_set_vring_enable_exec(struct vu_dev *vdev, >>>> return false; >>>> } >>>> >>>> +/** >>>> + * vu_set_send_rarp_exec() - Broadcast a fake RARP to notify the migration >>>> + * is terminated >>> >>> Fine, so we need to add this. >>> >>> But can we at least make it clear for our future benefit? That is, >>> there's no such thing as "fake RARP". The only thing that's actually >>> fake here is this callback. For others, see thread at: >>> >>> https://lore.kernel.org/qemu-devel/20250121100029.1106973-1-lvivier@redhat.com/ >>> >>> What about "Do nothing to silence QEMU bogus error message"? Claiming >>> we are broadcasting a RARP message and not doing it is... confusing. >> >> I think it's interesting to have this comment as it comes from the vhost-user >> specification as it describes the aim of the command, and we can add something like "but >> as passt don't need to update any ARP table we do nothing only to silence QEMU bogus error >> message". > > Eh, if we're already making it verbose, maybe we can go with something > like: > > vhost-user specification says: "Broadcast ...", but passt ... As you prefer... If you want you can update the patch when you commit it. > >>>> + * @vdev: vhost-user device >>>> + * @vmsg: vhost-user message >>>> + * >>>> + * Return: False as no reply is requested >>>> + */ >>>> +static bool vu_send_rarp_exec(struct vu_dev *vdev, >>>> + struct vhost_user_msg *msg) >>>> +{ >>>> + char macstr[ETH_ADDRSTRLEN]; >>>> + >>>> + (void)vdev; >>>> + >>>> + /* ignore the command */ >>>> + >>>> + debug("Ignore command VHOST_USER_SEND_RARP from %s", >>> >>> This is also a bit confusing, but I'm not sure I got it right. >>> >>> We don't actually get any message *from* the guest, correct? We get a >>> message from QEMU telling us we should send a RARP broadcast *for* a >>> given MAC address...? If I got it right, s/from/for/? >> >> Yes, you're right. >> The purpose of this debug message was to identify for :) which interface QEMU wants this >> broadcast. >> >>> >>>> + eth_ntop((unsigned char *)&msg->payload.u64, macstr, >>>> + sizeof(macstr))); >>>> + >>>> + return false; >>>> +} >>>> + >>>> /** >>>> * vu_set_migration_watch() - Add the migration file descriptor to epoll >>>> * @vdev: vhost-user device >>>> @@ -1177,6 +1202,7 @@ static bool (*vu_handle[VHOST_USER_MAX])(struct vu_dev *vdev, >>>> [VHOST_USER_SET_VRING_CALL] = vu_set_vring_call_exec, >>>> [VHOST_USER_SET_VRING_ERR] = vu_set_vring_err_exec, >>>> [VHOST_USER_SET_VRING_ENABLE] = vu_set_vring_enable_exec, >>>> + [VHOST_USER_SEND_RARP] = vu_send_rarp_exec, >>>> [VHOST_USER_SET_DEVICE_STATE_FD] = vu_set_device_state_fd_exec, >>>> [VHOST_USER_CHECK_DEVICE_STATE] = vu_check_device_state_exec, >>>> }; > Thanks, Laurent