From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-dl1-f73.google.com (mail-dl1-f73.google.com [74.125.82.73]) (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 2A39A38551C for ; Fri, 27 Feb 2026 20:35:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.82.73 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772224534; cv=none; b=QhzjoSFXJMr6QJPJXJrrhvQepNnRoiQmkCHjLNi2obs1SDF5iTRn5HVakC6shxz+XSd4Qnxw4McuvYcE9iKI8EpyMU62lPDx8MFzIDaApDQraTe8pjAG/LAcKvbA6uPpaIMHfocW2GW5DmbSRwVUjAf7dIpLxIN5jd/uMBN2C/k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772224534; c=relaxed/simple; bh=rjHPintehtxkM9UQsRWMqrYGwY/SaNBxtvh2ru+FDpM=; h=Date:Mime-Version:Message-ID:Subject:From:To:Cc:Content-Type; b=LmguNtT0ZgnvTTE16lCsZmftvr/n2FuKYF2nOjeW+wDL4ujM22Fb60WShkmj33oU8UzdPr6s2uC0iR7uLGMpn6yAbGy8VE7144rmB8QhQ0SxutNq9ENhxVavOiplkj2baAJE688NfPfDSLwymZuvBhZ29tZIEou0uY0jp1OuH0w= 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=R0iUrGgo; arc=none smtp.client-ip=74.125.82.73 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="R0iUrGgo" Received: by mail-dl1-f73.google.com with SMTP id a92af1059eb24-12711967e0eso3312458c88.0 for ; Fri, 27 Feb 2026 12:35:32 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1772224531; x=1772829331; darn=vger.kernel.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=nRaIjBVYslTopVZnWl1PKdjxejATawghymOdcPvjdcM=; b=R0iUrGgol4tL9q70rFD9WqTyanQutyR67QvrPGpLZ5YfxRdlxNatDfKbkBM4ycM4N1 9gyfQnJqwq8X0UmH8YQVHTEAUfopPcMJ/n5LdmxwWiBC7BoYsH5kixJRYNmwLsFwZJnq sBnTsEOm/xoPy/Ii+h0jYkzGnXX1wJ9XqGPvUuF+1roJod37jD56OFZOdnRvtN5bzr9x 9q0kxt5sFpTKSx/dsJubyTSYprrAM7WYf6qcK0azms57JoT3/t8Ga9af2WVP2Kue64+Y /ZI6RpyUepX1Zbm8A713ZgKJnTkT6ZAroLD4GvH2cCTo6/Mt8izN9F/xHGl/mszheDmg itmA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1772224531; x=1772829331; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=nRaIjBVYslTopVZnWl1PKdjxejATawghymOdcPvjdcM=; b=j+0uz2jrhu98/LubPhwkAN7poBijqoafxsRfpVD+zhkqPLsvJusUxWim3J84Is+k4r FA1hL24TLFn/gMZbnC1MXpr5+r59bcd8YhQ5XiocxygVb2WZoDedEKYBE1iJ3pGNIJ5+ f0rIbkNmPkJqUsMsgK3z38LkBSuIiuy8uEEMnOtmOfmLlgTFqUhotQl5wC6eghsNwJKZ kzEvRN9WM7LWLa8/x0euh+A7mHYnbuTxa/zGuqSq3alI38LH8dxibv1IlGOz8LoILo3e EiRxV8/YofgYV73fH7sn77ewtM6np5+058Azt/Kbidn0r4CF8OILQfXFDIYFv0G9lsyR Y5LA== X-Gm-Message-State: AOJu0YzXr0bFPWXhEiyyxkZXwqaEv9/ZCScyfXES/MeRW2ETshuJDdCd qDsw4MX3kRKCC/TKRvzT9gPVTvBYfQS9qYFgfuz5ckqiC/W/hUzxsowchY8rcCkV+rWVbegGH+W on/LHZULpw/+dMog9LLh/PqqJNw== X-Received: from dlj37.prod.google.com ([2002:a05:7022:525:b0:127:16fc:ca92]) (user=srutherford job=prod-delivery.src-stubby-dispatcher) by 2002:a05:7022:43aa:b0:119:e56c:18be with SMTP id a92af1059eb24-1278fc8a31cmr1426907c88.38.1772224529468; Fri, 27 Feb 2026 12:35:29 -0800 (PST) Date: Fri, 27 Feb 2026 20:34:56 +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: <20260227203457.558196-1-srutherford@google.com> Subject: [RFC PATCHv2 0/1] idpf: IDPF + SWIOTLB Bug From: Steve Rutherford To: Tony Nguyen , Przemek Kitszel , aleksander.lobakin@intel.com, "David S. Miller" , Jakub Kicinski , Eric Dumazet , intel-wired-lan@lists.osuosl.org Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, David Decotigny , Anjali Singhai , Sridhar Samudrala , Brian Vazquez , Li Li , emil.s.tantilov@intel.com, 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. v2 - Updated title and tags based on feedback. Steve Rutherford (1): idpf: 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