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([2a01:e0a:e10:ef90:343a:68f:2e91:95c]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-38bf3221db2sm16571188f8f.29.2025.01.22.09.22.06 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 22 Jan 2025 09:22:06 -0800 (PST) Message-ID: <28e3e395-0eaa-4eeb-bd61-1cb031d8da7f@redhat.com> Date: Wed, 22 Jan 2025 18:22:06 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] vhost-user: Silence unsupported VHOST_USER_PROTOCOL_F_RARP error To: Stefano Garzarella Cc: "Michael S. Tsirkin" , qemu-devel@nongnu.org, Jason Wang References: <20250121100029.1106973-1-lvivier@redhat.com> <3mcx7u456pawkgz4dgf6tvk7izczuy55guipqacqkl66jhtltq@fofd5u3el4nj> <20250122085828-mutt-send-email-mst@kernel.org> <044af96f-791b-471f-ae90-c17597445fd3@redhat.com> Content-Language: en-US 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: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.129.124; envelope-from=lvivier@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -50 X-Spam_score: -5.1 X-Spam_bar: ----- X-Spam_report: (-5.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-2.996, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=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: 2.1.29 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 On 22/01/2025 17:51, Stefano Garzarella wrote: > On Wed, Jan 22, 2025 at 05:41:15PM +0100, Laurent Vivier wrote: >> On 22/01/2025 17:20, Stefano Garzarella wrote: >>> On Wed, Jan 22, 2025 at 08:59:22AM -0500, Michael S. Tsirkin wrote: >>>> On Wed, Jan 22, 2025 at 02:42:14PM +0100, Stefano Garzarella wrote: >>>>> On Tue, Jan 21, 2025 at 11:00:29AM +0100, Laurent Vivier wrote: >>>>>> In vhost_user_receive() if vhost_net_notify_migration_done() reports >>>>>> an error we display on the console: >>>>>> >>>>>>   Vhost user backend fails to broadcast fake RARP >>>>>> >>>>>> This message can be useful if there is a problem to execute >>>>>> VHOST_USER_SEND_RARP but it is useless if the backend doesn't >>>>>> support VHOST_USER_PROTOCOL_F_RARP. >>>>>> >>>>>> Don't report the error if vhost_net_notify_migration_done() >>>>>> returns -ENOTSUP (from vhost_user_migration_done()) >>>>>> >>>>>> Update vhost_net-stub.c to return -ENOTSUP too. >>>>>> >>>>>> Signed-off-by: Laurent Vivier >>>>>> --- >>>>>> hw/net/vhost_net-stub.c | 2 +- >>>>>> net/vhost-user.c        | 2 +- >>>>>> 2 files changed, 2 insertions(+), 2 deletions(-) >>>>>> >>>>>> diff --git a/hw/net/vhost_net-stub.c b/hw/net/vhost_net-stub.c >>>>>> index 72df6d757e4d..875cd6c2b9c8 100644 >>>>>> --- a/hw/net/vhost_net-stub.c >>>>>> +++ b/hw/net/vhost_net-stub.c >>>>>> @@ -93,7 +93,7 @@ void vhost_net_config_mask(VHostNetState >>>>> *net, VirtIODevice *dev, bool mask) >>>>>> >>>>>> int vhost_net_notify_migration_done(struct vhost_net *net, char* mac_addr) >>>>>> { >>>>>> -    return -1; >>>>>> +    return -ENOTSUP; >>>>>> } >>>>>> >>>>>> VHostNetState *get_vhost_net(NetClientState *nc) >>>>>> diff --git a/net/vhost-user.c b/net/vhost-user.c >>>>>> index 12555518e838..636fff8a84a2 100644 >>>>>> --- a/net/vhost-user.c >>>>>> +++ b/net/vhost-user.c >>>>>> @@ -146,7 +146,7 @@ static ssize_t >>>>> vhost_user_receive(NetClientState *nc, const uint8_t *buf, >>>>>> >>>>>>          r = vhost_net_notify_migration_done(s->vhost_net, mac_addr); >>>>>> >>>>>> -        if ((r != 0) && (display_rarp_failure)) { >>>>>> +        if ((r != 0) && (r != -ENOTSUP) && (display_rarp_failure)) { >>>>>>              fprintf(stderr, >>>>>>                      "Vhost user backend fails to broadcast fake RARP\n"); >>>>>>              fflush(stderr); >>>>>> -- >>>>>> 2.47.1 >>>>>> >>>>> >>>>> IIUC the message was there since the introduction about 10 years ago >>>>> from commit 3e866365e1 ("vhost user: add rarp sending after live >>>>> migration for legacy guest"). IIUC -ENOTSUP is returned when both F_RARP >>>>> and F_GUEST_ANNOUNCE are not negotiated. >>>>> >>>>> That said, I honestly don't know what F_RARP or F_GUEST_ANNOUNCE is for, >>>> >>>> rarp is to have destination host broadcast a message with VM address >>>> to update the network. Guest announce is when it will instead >>>> ask the guest to do this. >>> >>> Okay, thanks for explaining to me. >>> So if both features are not negotiated, no one is going to broadcast >>> the message, right? >>> >>> Could that be a valid reason to print an error message in QEMU? >>> >>> To me it might be reasonable because the user might experience some >>> network problems, but I'm not a network guy :-) >> >> I'm working on adding vhost-user to passt[1], and in this case we don't need to >> broadcast any message. > > Okay, so please can you add that to the commit description and also > explaining why you don't need that? > >> >> So I don't implement VHOST_USER_SEND_RARP and I don't want the error message to spoil my >> console. > > Fair enough, but at that point, if it's valid to have both feature not > negotiated, IMHO is better to return 0 in vhost_user_migration_done(). > Maybe adding also a comment to explain that in your scenario you don't > need to do nothing (like if guest supports GUEST_ANNOUNCE). I agree. > >> >> -ENOTSUP is an error message for developer not for user. > > I was referring to the "Vhost user backend fails to broadcast fake RARP" > error message we are skipping here. So in the end my real question at this point is: is it better to suppress the error message in QEMU (1) or implement an empty VHOST_USER_SEND_RARP in Passt (2)? As this discussion is going on I'm no longer sure that (1) is the right one. Thanks, Laurent