From nobody Fri Sep 26 00:58:12 2025 X-Original-To: net@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4cXsf80rWZz68w5J; Fri, 26 Sep 2025 00:58:40 +0000 (UTC) (envelope-from lists@jnielsen.net) Received: from webmail5.jnielsen.net (webmail5.jnielsen.net [IPv6:2607:f170:34:11::b0]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "mail.freebsdsolutions.net", Issuer "R13" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4cXsf64KWSz3Qnj; Fri, 26 Sep 2025 00:58:38 +0000 (UTC) (envelope-from lists@jnielsen.net) Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=none; spf=pass (mx1.freebsd.org: domain of lists@jnielsen.net designates 2607:f170:34:11::b0 as permitted sender) smtp.mailfrom=lists@jnielsen.net Received: from smtpclient.apple ([IPv6:2607:fa18:e2fe:2d6a:e55f:7fce:3072:eb05]) (authenticated bits=0) by webmail5.jnielsen.net (8.18.1/8.18.1) with ESMTPSA id 58Q0wNZN037575 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Thu, 25 Sep 2025 18:58:26 -0600 (MDT) (envelope-from lists@jnielsen.net) X-Authentication-Warning: webmail5.jnielsen.net: Host [IPv6:2607:fa18:e2fe:2d6a:e55f:7fce:3072:eb05] claimed to be smtpclient.apple From: John Nielsen Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable List-Id: Networking and TCP/IP with FreeBSD List-Archive: https://lists.freebsd.org/archives/freebsd-net List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-net@FreeBSD.org Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3826.700.81\)) Subject: Chelsio (cxgbe) VF on FreeBSD guest under KVM requires -rxcsum Message-Id: <5D2A2499-4B43-4FE6-AA5A-AD334BC4E872@jnielsen.net> Date: Thu, 25 Sep 2025 18:58:12 -0600 Cc: np@freebsd.org To: net@freebsd.org, virtualization@freebsd.org X-Mailer: Apple Mail (2.3826.700.81) X-Spamd-Bar: -- X-Spamd-Result: default: False [-2.87 / 15.00]; NEURAL_HAM_SHORT(-1.00)[-1.000]; NEURAL_HAM_MEDIUM(-0.95)[-0.950]; NEURAL_HAM_LONG(-0.62)[-0.622]; R_SPF_ALLOW(-0.20)[+mx]; MIME_GOOD(-0.10)[text/plain]; APPLE_MAILER_COMMON(0.00)[]; RCVD_TLS_ALL(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; RCVD_COUNT_ONE(0.00)[1]; ARC_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; DMARC_NA(0.00)[jnielsen.net]; MID_RHS_MATCH_FROM(0.00)[]; MLMMJ_DEST(0.00)[virtualization@freebsd.org,net@freebsd.org]; FROM_HAS_DN(0.00)[]; HAS_XAW(0.00)[]; R_DKIM_NA(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; TO_DN_NONE(0.00)[]; RCPT_COUNT_THREE(0.00)[3] X-Rspamd-Queue-Id: 4cXsf64KWSz3Qnj Hi- Not sure if this is a known issue or even an issue on the FreeBSD side = but decided to ask here first. I=E2=80=99m happy to put in a bug report = if appropriate. I have a hypervisor machine running Arch Linux with KVM, Qemu and = libvirtd. The machine has a Chelsio T520-CR adapter. I recently began = passing through virtual functions of the NIC to several of the guests I = run on the hypervisor. One of the guests runs Windows 11, and the change = was seamless. Two of the guests are running FreeBSD (14.3 or so). On = each of them the VFs were readily identified and configured (using DHCP = in one case), and ping and ARP appeared to work fine. However, TCP and = UDP traffic to the guests never received a response. After some = head-scratching and troubleshooting I discovered that running = =E2=80=9Cifconfig cxlv0 -rxcsum=E2=80=9D immediately allowed traffic to = flow as expected. As workarounds go that isn=E2=80=99t terrible, but I was surprised that = the FreeBSD guests required this adjustment while the Windows one did = not. As a point of reference I have another hypervisor machine that runs = FreeBSD 14-STABLE. It also has a Chelsio T520-CR adapter. FreeBSD guests = on that machine do not require =E2=80=9C-rxcsum=E2=80=9D in order to use = the Chelsio virtual functions. Let me know if anyone can shed some light on this. I=E2=80=99m happy to = provide additional details or run further tests if needed. Thank you! -John