From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: passt.top; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: passt.top; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=SPg4hm96; dkim-atps=neutral Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by passt.top (Postfix) with ESMTP id 81B3B5A004E for ; Fri, 15 Nov 2024 12:13:30 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1731669209; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=J1/8aj7Khi+onP7rScBdy+BYpPukW1Z/XPshBQ7QaAU=; b=SPg4hm96y5NsaTHiCMmCK2ft7Xw8AWQi1aNJ3S+AwICxE+hGjfpGRqlBf+BrOJpEjIClvA ZCs2JA6H5steLT3J3xJwWYSnoD8Z94TcI4ErwHbtFZePlKJHpuRWV3kNGbE3zdGtDQFcK9 X4WlvqWBBJJc8a1NmGpF9oy0hnyyo94= Received: from mail-wr1-f71.google.com (mail-wr1-f71.google.com [209.85.221.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-564-4UISX_uzOU-YMvYAUCr7zQ-1; Fri, 15 Nov 2024 06:13:27 -0500 X-MC-Unique: 4UISX_uzOU-YMvYAUCr7zQ-1 X-Mimecast-MFC-AGG-ID: 4UISX_uzOU-YMvYAUCr7zQ Received: by mail-wr1-f71.google.com with SMTP id ffacd0b85a97d-37d4854fa0eso1071638f8f.2 for ; Fri, 15 Nov 2024 03:13:27 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1731669206; x=1732274006; h=content-transfer-encoding:in-reply-to:autocrypt:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=J1/8aj7Khi+onP7rScBdy+BYpPukW1Z/XPshBQ7QaAU=; b=JWwrRtClmhMcAjiLg5kV3cPYHPRZQZEFmILx4LWu9mstjegaXIsiqPa3/7+xBC3vft Oud++pa5KzgobilokUkRJX1gahdZaNCprtmBI5Sn44tF9N7sPxss5w6BCx/IJLcK6ZTu gs5mI0rpzTSFnfUFxbNf4Yu9tw3+U0fMUrHcfE40gwg+q4gDZCetBU4AIIGiIBYkrVxC 3l2J9+5wM7D6RHPFujGYSkuiZGL0BHyCOAxQv6fV191HxNYa+qWdXbrSjIJiI4I8mV6F hQfMUFj0K7h59enjkvxOeBggOzabuOUiJ0+sLuhyRUYV+LYUKCZO4lRj4pcNNOUq5qD4 qNmA== X-Gm-Message-State: AOJu0YzaSJVtIE3Y1pGIjdskjDnnqBe8rRaNedEGsdptVRMRUoRICKJp QmGXKDlBJDSzBqtoLGJow1OBrCD1KjofosJ71BGnGD9THDMJ2mpLdVZyYaHdc9aH+MuPGaYYCwp S1TQ5znomFsZsNmIEhDSTUeJ0zwYuq4qGemUtxPDRiZmOtXT3sQ== X-Received: by 2002:a05:6000:1543:b0:382:228b:4c34 with SMTP id ffacd0b85a97d-382258f0863mr1700878f8f.2.1731669206429; Fri, 15 Nov 2024 03:13:26 -0800 (PST) X-Google-Smtp-Source: AGHT+IF+BTTXKNm7+jzHTaic71rQ2cALwwr2RusLHzBa0Y/es+bHD9PxSENqhVWrzCcRXCVhyoxVjQ== X-Received: by 2002:a05:6000:1543:b0:382:228b:4c34 with SMTP id ffacd0b85a97d-382258f0863mr1700803f8f.2.1731669204949; Fri, 15 Nov 2024 03:13:24 -0800 (PST) Received: from ?IPV6:2a01:e0a:e10:ef90:343a:68f:2e91:95c? ([2a01:e0a:e10:ef90:343a:68f:2e91:95c]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-3821ae16170sm4085992f8f.69.2024.11.15.03.13.24 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 15 Nov 2024 03:13:24 -0800 (PST) Message-ID: <7593b3ea-c3ad-445d-b737-87f42f74e5b0@redhat.com> Date: Fri, 15 Nov 2024 12:13:23 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v8 7/8] vhost-user: add vhost-user To: Stefano Brivio References: <20241010122903.1188992-1-lvivier@redhat.com> <20241010122903.1188992-8-lvivier@redhat.com> <20241017021034.437f3757@elisabeth> <20241114152319.722bff4e@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: <20241114152319.722bff4e@elisabeth> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: JKKl9aPNrIkQaxJD9QpzKMTupe1d09GrS_a-pNBPwRY_1731669206 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: AZHUHUMBFTVNRKFQVVXJSNHOCBGNRJBW X-Message-ID-Hash: AZHUHUMBFTVNRKFQVVXJSNHOCBGNRJBW 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 14/11/2024 15:23, Stefano Brivio wrote: > On Thu, 14 Nov 2024 11:29:36 +0100 > Laurent Vivier wrote: > >> On 17/10/2024 02:10, Stefano Brivio wrote: >>>> +/** >>>> + * tcp_vu_prepare() - Prepare the packet header >>>> + * @c: Execution context >>>> + * @conn: Connection pointer >>>> + * @first: Pointer to the array of IO vectors >>>> + * @dlen: Packet data length >>>> + * @check: Checksum, if already known >>>> + */ >>>> +static void tcp_vu_prepare(const struct ctx *c, >>>> + struct tcp_tap_conn *conn, struct iovec *first, >>>> + size_t dlen, const uint16_t **check) >>>> +{ >>>> + const struct flowside *toside = TAPFLOW(conn); >>>> + char *base = first->iov_base; >>>> + struct ethhdr *eh; >>>> + >>>> + /* we guess the first iovec provided by the guest can embed >>>> + * all the headers needed by L2 frame >>>> + */ >>> What happens if it doesn't (buggy guest)? Do we have a way to make sure >>> it's the case? I guess it's more straightforward to do this in >>> tcp_vu_data_from_sock() where we check and set iov_len (even though the >>> implication of VIRTIO_NET_F_MRG_RXBUF isn't totally clear to me). >> >> According to spec, minimum size of a buffer is 1526 bytes >> (https://docs.oasis-open.org/virtio/virtio/v1.2/csd01/virtio-v1.2-csd01.html#x1-2340003) >> >> So if the guest is buggy, we will write in the guest memory out of the (buggy) provided >> buffer, and we can crash the guest. But it's what happens to a buggy guest. >> >> We can't fix the guest, IMO passt should crash in this case (add an ASSERT()?). > > I think we should rather call tap_sock_reset() (see tap_passt_input()) > so that the guest has a chance to reconnect (you implemented this in > QEMU...). > If I add a call to tap_sock_reset() in tcp_vu_data_from_sock(), I need to remove all the "const" from "struct ctx *" in the entire call chain. It's a lot. I'm not sure it is worth it. Thanks, Laurent