From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f172.google.com (mail-pl1-f172.google.com [209.85.214.172]) (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 A7D0A241672; Mon, 24 Feb 2025 17:38:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740418716; cv=none; b=jx4UkXDDSuqqcS4t9eQNmghXiKsTheYBtKBW4j6ETRFuuLpXRERdmWi1cn1S5RcAfsM5m3g0liYqHEGahgZizIdEHsG9uH6OlLV5WTc0W6Gca5UScrpuX4zgj7kFrJA5EgAh6OcBm5RjgxEY5wjwpdcblcUvfOeRQ/eN3ljd9Fk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740418716; c=relaxed/simple; bh=6WDWAvw45opfe01BXQoV2J9T4wPwlIJFh7kOtE0s2h4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=aSAdVv8czAxJ8PsgChdkjs3/e5w9oxNxHsTbpsMiKWaYkfIKJ9gaZPV5uD78HRk1Al+yjVcoW3QtKXcauCR1MKGqx1waA4e3Wgzf6glDrRQY4ZIhS/mig2SdrMusEaDJxHImpa84omSTkiwjevP121H9wpPbCpuUSdxfmoLl/Ew= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=iVNK6mYo; arc=none smtp.client-ip=209.85.214.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="iVNK6mYo" Received: by mail-pl1-f172.google.com with SMTP id d9443c01a7336-22114b800f7so92976915ad.2; Mon, 24 Feb 2025 09:38:34 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1740418714; x=1741023514; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=UX4AozQfD/+Q4V/98VBsuhZOuZnT8f3wxe/fXFwxJI4=; b=iVNK6mYorVZzauYVlIHk8GzKlnDk5Jsk3YDog+Zw1dvhbyLMsBaSAntmIAAOazF6UM thF1SxQBtRGP83ZS09ZlPwkedfallZZNqA0bNp6hGGXbE/LvbuPrxqW96Vs5dRFMm6+T Y3UK+ToD3QWW2kk/5J7eoBdn17aY6+1dZVsthjIY3s0T36nIyNowBKqz9Zt0PjOluQ0J +Kdada0LjmasYMCO5I8vhMGnGRcY2Kji+OEgsF4DeaBuSkUFQUasCFlPbKOeIoo/caYr gEgaQ8+ijvVqKtCqPY8eh4t5xACpDR3wM8SghYYBkMV47Ydrh73/n6l8KfP7IyB9jT2Y TTRA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1740418714; x=1741023514; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=UX4AozQfD/+Q4V/98VBsuhZOuZnT8f3wxe/fXFwxJI4=; b=upeX4eWudrjU8HjXUmoZO45kaax2q5Na16N4SV7nBW/E3W5+mvaRqiQCy+9uGmqgdV zC5xU5uVpLiCnLEMQ140QTC4pFGisRJfudK96jq7NaKqHeaMiP660CL5chRMX6/PnIat recSKu6P1wKGJDa4jJLGthXZR1/ZcxfOHHfca2TSwDhWKMIA30jPHP5C5vuhRlscHWTK 4b2GwFPToSkif3mjiin4bIXcoJONAm2dPhAqokoLp0I9Qlz0am30mhQoO2Axx7ftNy/4 FvZ66jzh91c6sU9xITFS6i03LksxYPLVF3ErJ7uZwAuWQRMK5fqNr+iVhBeQ623Dulfl p3vQ== X-Forwarded-Encrypted: i=1; AJvYcCWMTuUY9+jLFL3LU24FE6atnt+qosKRHYMOnzsAEBJ4HyClSQ/KinQwFzlBg72SPJnIxjs=@vger.kernel.org, AJvYcCXlYyCK2KI6vk14djAGGDu4f1PydaL28sBN4DhV23j8W5fl+TNCT6Nk4BMbmQbELnPTciQo3Lc+qptCOpJr@vger.kernel.org, AJvYcCXq2sAu+6XRbje0rni/rTyBL4o5CMB/V1BAESs0c8RH1zjByke68sJeJkxfk8uSTikpc3ndlWiMFo0EXZY8cobU@vger.kernel.org, AJvYcCXsCltWgBoPWLe7/kNccPBXTdWcJePv836BGXDfExukRymhQ3PJOMqgpdLjbFnivht9pXz8jznr4LAP@vger.kernel.org X-Gm-Message-State: AOJu0Yy7heTDBaTQNtCYFbDwi5XMswPGje96tOaOu65XUn12n/i1XY1E 68Nnt1pmZ7RLWOZZLwnY3eeCl0LxM8T1yzw0s6PCJc3UC21yyI4= X-Gm-Gg: ASbGncv/12qfVcR7eNsixkmnXlAzDDmZXeEaaneGwqEo4md+OVJ2zN9ZNqZUjifPqSq FWtTsawAUOUPjSlIvp/gMNdyKd8N8dfb6k/MnQlQbU3m2U0v4QXzpEsgoB3AtUf+V55fHKBtw5/ 7L0sOZk2hxZNUaLO4QAtq9IS9VIVVg2pttkDZJnA1OZs+j9jCGIc2gDx4UiaBpp2RUJsxQ8B2za 1fcKl+ccjFbzYcOXNzt4A5LGKTW/D5HBkUSNmyDgkFHh5TdoNdAbj0O/W55f5KgF1eg1QIpuaEf W9S3pgLWQM4rg07LrzgjsOEa8w== X-Google-Smtp-Source: AGHT+IEOY3jvw3d20B761rhLccrQlmDTz3/D4N2sGGq3MNqiiZ11e3nLJ+fNVmPINvJS8+U0KTPG+Q== X-Received: by 2002:a17:902:f550:b0:220:e63c:5b13 with SMTP id d9443c01a7336-2219fff4ef2mr211596935ad.46.1740418713456; Mon, 24 Feb 2025 09:38:33 -0800 (PST) Received: from localhost ([2601:646:9e00:f56e:123b:cea3:439a:b3e3]) by smtp.gmail.com with UTF8SMTPSA id d9443c01a7336-220d534afadsm185575355ad.26.2025.02.24.09.38.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 24 Feb 2025 09:38:32 -0800 (PST) Date: Mon, 24 Feb 2025 09:38:32 -0800 From: Stanislav Fomichev To: Mina Almasry Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, virtualization@lists.linux.dev, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org, Donald Hunter , Jakub Kicinski , "David S. Miller" , Eric Dumazet , Paolo Abeni , Simon Horman , Jonathan Corbet , Andrew Lunn , Jeroen de Borst , Harshitha Ramamurthy , Kuniyuki Iwashima , Willem de Bruijn , David Ahern , Neal Cardwell , Stefan Hajnoczi , Stefano Garzarella , "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , Eugenio =?utf-8?B?UMOpcmV6?= , Shuah Khan , sdf@fomichev.me, asml.silence@gmail.com, dw@davidwei.uk, Jamal Hadi Salim , Victor Nogueira , Pedro Tammela , Samiullah Khawaja , Kaiyuan Zhang Subject: Re: [PATCH net-next v5 3/9] net: devmem: Implement TX path Message-ID: References: <20250222191517.743530-1-almasrymina@google.com> <20250222191517.743530-4-almasrymina@google.com> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20250222191517.743530-4-almasrymina@google.com> On 02/22, Mina Almasry wrote: > Augment dmabuf binding to be able to handle TX. Additional to all the RX > binding, we also create tx_vec needed for the TX path. > > Provide API for sendmsg to be able to send dmabufs bound to this device: > > - Provide a new dmabuf_tx_cmsg which includes the dmabuf to send from. > - MSG_ZEROCOPY with SCM_DEVMEM_DMABUF cmsg indicates send from dma-buf. > > Devmem is uncopyable, so piggyback off the existing MSG_ZEROCOPY > implementation, while disabling instances where MSG_ZEROCOPY falls back > to copying. > > We additionally pipe the binding down to the new > zerocopy_fill_skb_from_devmem which fills a TX skb with net_iov netmems > instead of the traditional page netmems. > > We also special case skb_frag_dma_map to return the dma-address of these > dmabuf net_iovs instead of attempting to map pages. > > Based on work by Stanislav Fomichev . A lot of the meat > of the implementation came from devmem TCP RFC v1[1], which included the > TX path, but Stan did all the rebasing on top of netmem/net_iov. > > Cc: Stanislav Fomichev > Signed-off-by: Kaiyuan Zhang > Signed-off-by: Mina Almasry Acked-by: Stanislav Fomichev (assuming Eric/Willem will also take a look at this)