From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-dy1-f202.google.com (mail-dy1-f202.google.com [74.125.82.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BAD20301037 for ; Fri, 27 Feb 2026 02:59:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.82.202 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772161197; cv=none; b=glnhWzcs0P++DkVOTdhnCWIIel40Pkv4z/Vcu5EnwuWdaMC8ZfYU3/xndkH2lOEKRBvlqHa40qJQrCGxhcw+8JbgLXPxgsPd4A7FxLRxriW4TLzmWpSy3tYoEeGyYVbvneSOFR1Ehyrt1glwU4nrBQBhAs3/ungNMVlwHpqbH98= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772161197; c=relaxed/simple; bh=//7wOODElqYTQiR8nL5gR7HXR2TzZyBl5X8K0sjoxBc=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=EoeKDZqelmvEMqFOnoyNTqih6+LFVXl7UIJM68xetSxI6f6kfaSPBvtVyB+/GIoHpzMfvaD+//tHyIP9UAwD7NQQUg6klBLJynHvVqXgUCRmJmSyqhSTBTHUzJRdQgr1ty7dLWqG0Bd21yLBlsENkEclHbbdHp7Oq9MVbnKB3y8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--srutherford.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=N1mMakp/; arc=none smtp.client-ip=74.125.82.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--srutherford.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="N1mMakp/" Received: by mail-dy1-f202.google.com with SMTP id 5a478bee46e88-2ba8013a9e3so1565635eec.0 for ; Thu, 26 Feb 2026 18:59:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1772161194; x=1772765994; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=C05Mn9JMafI99EWEgRgLLPj/E+g1PjLcWaGlhM4Kvtg=; b=N1mMakp/shPkrt0fOI3qBu/xpT6epAxtg7spoYTucgO6HWxx2rQPUlcI7MC1tBbzeT B4ZA8NNJSAD0fIJEcJIECrv7LjcC/VCpayWnG8jFIvu3t9/cN19VRB754M1s5689lAPA So3c87uL32ag9YFAKDWF4QzXpyiDry4PyRiSswPxSths4Tp9jCqffL3NFO3CojbtdOal bMJIRafZVzSuZXbgF6RLLKu8naV4aKxPjI6uwa+YjY9yen12+C+1uIfGgQkjGYvmNBnU 2g9BBGIK2bCDnHwSSvA0pEKpK92Tz6SVa1+Ex4IkF9AHiTJ9q4MK8fju+dW5OHLb7WSL rC8Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1772161194; x=1772765994; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=C05Mn9JMafI99EWEgRgLLPj/E+g1PjLcWaGlhM4Kvtg=; b=wvvFu9JKQGsm54PHw9gNd0/Kg3T73MKFXmMMYGfvwGug65fwkZoETddhrHfpMhYARW IkdcFABvYfit3zg2gAWJV4sDH6HnaKM+homMYHDShdd9Oej5ZfBgjJt0FdDmt781/QyT jPnd8d5f7MDB6QwBu70GgQU1aq2KXWBRnPqiA0yufqC7648ctxqVQtcyekXdbc/bGIgH kDCEUNoWBcnw7dlgSBQOMvMChUzOvMVwtNDdVD2Ve4bj+R/GC1sgBURwjnmvoHxTqHjF Tjo29i3Pc+pdnMFTYWrglLa+38N/UsBpH0262zMXyFH8neJQaYeSE9Z3L7gWIkCXUSND 49cQ== X-Forwarded-Encrypted: i=1; AJvYcCXLmSJpNIcv8R35zWbzOYtAxpW3cCfg499vp21XNANY+nRVYswee2pHeJOD0ech4Jy8yo8cDCc=@vger.kernel.org X-Gm-Message-State: AOJu0YzV+YS6ENpHeQBgriwPZOoK7jB2UNbSqp2v8tvkWi4PZKYOW61Y aMtm1mBnhmKXT6Ed1g8nmdJgfkp79k2JbHTaMYq/bGb4WpXQuRG3H/JodEyXKPAKMSnkdk5Ojel 412YNEze1LakYjNHPkUwkG5KR7w== X-Received: from dlbcy24.prod.google.com ([2002:a05:7022:b98:b0:127:1b87:b031]) (user=srutherford job=prod-delivery.src-stubby-dispatcher) by 2002:a05:7022:6289:b0:124:a610:62f6 with SMTP id a92af1059eb24-1278fd340a7mr448355c88.44.1772161193541; Thu, 26 Feb 2026 18:59:53 -0800 (PST) Date: Fri, 27 Feb 2026 02:59:49 +0000 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.53.0.473.g4a7958ca14-goog Message-ID: <20260227025950.174755-1-srutherford@google.com> Subject: [RFC PATCH 0/1] IDPF + SWIOTLB Bug From: Steve Rutherford To: anthony.l.nguyen@intel.com, przemyslaw.kitszel@intel.com, aleksander.lobakin@intel.com Cc: andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Steve Rutherford Content-Type: text/plain; charset="UTF-8" Found an issue with the IDPF driver when SWIOTLB is enabled. The issue results in empty headers for packets that hit the split queue workaround path. It's caused by a spurious sync in that path. The header is synced from the SWIOTLB even when the header was shoved into the payload. I cooked up a sample patch, but I'm not an expert in this driver, so I have no idea if it's the right solution. It did allow my QEMU VM to boot with a superficially functional passed-through IDPF NIC and SWIOTLB=force. The patch was written against COS's 6.12, so I assume that it will not apply cleanly elsewhere, but I figured a wrong sample patch was better than a long paragraph describing the same thing. My read of more recent kernels is that this problem is still present, but could be mistaken. Steve Rutherford (1): Fix header clobber in IDPF with SWIOTLB enabled drivers/net/ethernet/intel/idpf/idpf_txrx.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) -- 2.53.0.473.g4a7958ca14-goog