From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.16]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A66A833AD8A; Mon, 16 Mar 2026 17:46:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.16 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773683204; cv=none; b=p3arKwtX51njlQ47+iO5tsSwhgmhltJvD/E0PzOEyYyHuUeFdT2hgkr7XVc5doMZGlZ3FXkhrPy9GIVe5ySAGt2c08e1ryKEyUaJ50to75UMDcYOuueBC5l1YxR/KFQMlT5TkRD3CJPnnhbCwFTLaITuM4EouJLCTAa36ew9RyA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773683204; c=relaxed/simple; bh=mUaN9OyVf9HbCRicI/4FWvNTeCTlSydlvJ4GVQj7bGg=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=bVYCy0u7FEVNk+7B1KPMO/R0CRaFpuZZCbN/LwkAVdd6Q2bf/PVmjKGFrQkB1hhxI6T1u1nB4RU7AifNhIgltctMLijJL3/4oUOEbzoM+lSTTZTcXmgbrQMFQZm1RpkeAWscLJlMlwPG68DnnXp2hmJTZsOZQ9p3CR41NXHDt6c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=N9nIBfdA; arc=none smtp.client-ip=192.198.163.16 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="N9nIBfdA" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1773683203; x=1805219203; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=mUaN9OyVf9HbCRicI/4FWvNTeCTlSydlvJ4GVQj7bGg=; b=N9nIBfdA5eTOnIo2ybZPu0jKt47wtfe2Y01cz1U79lPQy7iGM3Z2AtLP OK88nqZWgYwWH5e0yhY54/m70JTbldy/Kom5pyJnRRXA87Ko1RZK1kq9D iTe0YHetiOjeqnkx+tWx0sMXU7uBCEYW6oDNDUGorf302P0jGpcf32ibo GHr68RfrxZn2XX7YefWt0/i8irqMh9sKLgC5Vz2FmZQ98IpMKB7LQh6x4 oDBHgB3Dhj7lD+2japmdrkyl97a3PXyFQaMDXZqskO4b1RuifLb+fo4rd IwzwvQ5OAsAMbRGKXLLMahzbFoOZEgSuEqfBlzwb1/a0pkQ3yRBOvzCRG g==; X-CSE-ConnectionGUID: /qHtbq0RR+u3C6co0cQYEg== X-CSE-MsgGUID: Wn7P1qG9SV2LPkhwKSPjww== X-IronPort-AV: E=McAfee;i="6800,10657,11731"; a="62275721" X-IronPort-AV: E=Sophos;i="6.23,124,1770624000"; d="scan'208";a="62275721" Received: from orviesa008.jf.intel.com ([10.64.159.148]) by fmvoesa110.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Mar 2026 10:46:42 -0700 X-CSE-ConnectionGUID: uBqSR16yRUyCepRJfYKn8g== X-CSE-MsgGUID: uZAy85NtTji1O+vE+imavw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.23,124,1770624000"; d="scan'208";a="222075747" Received: from boxer.igk.intel.com ([10.102.20.173]) by orviesa008.jf.intel.com with ESMTP; 16 Mar 2026 10:46:40 -0700 From: Maciej Fijalkowski To: netdev@vger.kernel.org Cc: bpf@vger.kernel.org, magnus.karlsson@intel.com, stfomichev@gmail.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, larysa.zaremba@intel.com, aleksander.lobakin@intel.com, Maciej Fijalkowski Subject: [PATCH net 4/6] xsk: validate MTU against usable frame size on bind Date: Mon, 16 Mar 2026 18:45:48 +0100 Message-Id: <20260316174550.462177-5-maciej.fijalkowski@intel.com> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20260316174550.462177-1-maciej.fijalkowski@intel.com> References: <20260316174550.462177-1-maciej.fijalkowski@intel.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit AF_XDP bind currently accepts zero-copy pool configurations without verifying that the device MTU fits into the usable frame space provided by the UMEM chunk. This becomes a problem since we started to respect tailroom which is subtracted from chunk_size (among with headroom). 2k chunk size might not provide enough space for standard 1500 MTU, so let us catch such settings at bind time. This prevents creating an already-invalid setup and complements the MTU change restriction for devices with an attached XSK pool. Signed-off-by: Maciej Fijalkowski --- net/xdp/xsk_buff_pool.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/net/xdp/xsk_buff_pool.c b/net/xdp/xsk_buff_pool.c index 2cfc19e363e3..0a6d76df97dc 100644 --- a/net/xdp/xsk_buff_pool.c +++ b/net/xdp/xsk_buff_pool.c @@ -157,6 +157,7 @@ static void xp_disable_drv_zc(struct xsk_buff_pool *pool) int xp_assign_dev(struct xsk_buff_pool *pool, struct net_device *netdev, u16 queue_id, u16 flags) { + bool mbuf = flags & XDP_USE_SG; bool force_zc, force_copy; struct netdev_bpf bpf; int err = 0; @@ -178,7 +179,7 @@ int xp_assign_dev(struct xsk_buff_pool *pool, if (err) return err; - if (flags & XDP_USE_SG) + if (mbuf) pool->umem->flags |= XDP_UMEM_SG_FLAG; if (flags & XDP_USE_NEED_WAKEUP) @@ -200,11 +201,19 @@ int xp_assign_dev(struct xsk_buff_pool *pool, goto err_unreg_pool; } - if (netdev->xdp_zc_max_segs == 1 && (flags & XDP_USE_SG)) { + if (netdev->xdp_zc_max_segs == 1 && mbuf) { err = -EOPNOTSUPP; goto err_unreg_pool; } + if (!mbuf) { + if (netdev->mtu + netdev->hard_header_len > + xsk_pool_get_rx_frame_size(pool)) { + err = -EOPNOTSUPP; + goto err_unreg_pool; + } + } + if (dev_get_min_mp_channel_count(netdev)) { err = -EBUSY; goto err_unreg_pool; -- 2.43.0