From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 79B90CDB47E for ; Wed, 18 Oct 2023 18:40:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Jrap/YtB/Sd8Wus7hHKRx+7IUNmLTOe1yzTe7Ucyy5s=; b=ut4dhdMimdP50/3rHZy0rM0XDH 376ld+pBqKLHAFcakxPpWoZA7AjBViXnVKmK5axcip9vFp7m2igy4B9+e5rRdD6aamzYOpWVI86MX TNuliEfyaC4diHItolCTKA55iUbnvGauqS/rfqe5kGEl9wXJOrsHUfVhmoXR25OOykK4FxqEOuYVv erA6ou0B+oTIXGzCiu/MjAXY+zNn0i9+gBbTOrqzB1BepuOhg8Iglx/ZPbYFoe/2gcIHKaK+ngiRZ gJSlPlkxpnPIgHl6GwZLAm0VQdJAlTeWUlNyWT9poYO/+4HhT/wveOKui7d3JH76VhAwM0dWefrr/ Tm6C+vWw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qtBTJ-00FTmG-0A; Wed, 18 Oct 2023 18:40:45 +0000 Received: from mail-io1-xd2d.google.com ([2607:f8b0:4864:20::d2d]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qtBTE-00FTl8-1E for linux-nvme@lists.infradead.org; Wed, 18 Oct 2023 18:40:43 +0000 Received: by mail-io1-xd2d.google.com with SMTP id ca18e2360f4ac-79fab2caf70so58654539f.1 for ; Wed, 18 Oct 2023 11:40:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20230601.gappssmtp.com; s=20230601; t=1697654437; x=1698259237; darn=lists.infradead.org; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=Jrap/YtB/Sd8Wus7hHKRx+7IUNmLTOe1yzTe7Ucyy5s=; b=a5C7aFg5j97lF9rV1jTvukTOHG4Nf7ZR2tjzQUeOBNbI47RqfEM1C6dEc+hCAhAwta GwprDFAdaziUQ90plEWIiatd6qY68DsmUMeHkrhGoNsNKzxKQVO0rQmZckeDmr79938N QlE/kHBRCX9FKpPoVF+XTBN/cfTfXwfneF372nE1XdzlmK9k1rVu5wZqdgh4lT2v+v7o SFeHwJtavKQWSLuz6qAOtD3d1sWk6k6XW++qhribozNWpr6zlyIZdi+/gUqCwfUOcWKn UMOtE4tRX++ggdcWkxjaPX6igmfehak/joqOkUowmENwFCAx4V9VMUz0H+E81FjO+VzG tf/Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1697654437; x=1698259237; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=Jrap/YtB/Sd8Wus7hHKRx+7IUNmLTOe1yzTe7Ucyy5s=; b=HKLK0OrinhE2axITMPTpMfH2AEUOi0hhGYcxdz5dzBr36p5HuyL8flW5Fnah+I3gpF 8kDN0jYV4MyGHlVnvnXL6h5BIQucR3X9Jc9gEHzwTBStvx+Wz9E6uICealOcxIaTAtZ3 +SAonNgJTpFzKiCIz7bMqqrrKO/jTO5+4/jsWCKiUlt8/OB5bD2RxPFFKw2R3grqeSIi hhBOIDfJb3Va091N1KuxyQmVPdky4ulgqLwlQge+EF4mDZo2xtDE7W1dYvQr8k0DLrTf pqBpvNmXAamjUcNsxwt63ftcbyQTSKUh6DdO8cnmwkWYh84hSYcw/e+bW9XuLpQ76/+6 i0Ig== X-Gm-Message-State: AOJu0YxdzLPg/cVvh3O1OpYyHHCY63ZzOruwwpCEnbws3mBmbusBB3YG cN3OadsGIj5jhvg95Kld8Le/bg== X-Google-Smtp-Source: AGHT+IF/mw2nhMnShefoRjeknfThW7m2powVt1fzQRugKjjDxEyb9jncdBW+U6Mw21aiUl3At14ZmA== X-Received: by 2002:a92:d2ca:0:b0:34f:a4f0:4fc4 with SMTP id w10-20020a92d2ca000000b0034fa4f04fc4mr162371ilg.2.1697654437401; Wed, 18 Oct 2023 11:40:37 -0700 (PDT) Received: from [192.168.1.94] ([96.43.243.2]) by smtp.gmail.com with ESMTPSA id s5-20020a92cbc5000000b0035797ea96f7sm1298810ilq.9.2023.10.18.11.40.36 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 18 Oct 2023 11:40:36 -0700 (PDT) Message-ID: <2f6cdecc-d51b-4cbf-a0dd-ccd22fac8a98@kernel.dk> Date: Wed, 18 Oct 2023 12:40:35 -0600 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 0/2] Unprivileged sgl-only passthrough Content-Language: en-US To: Kanchan Joshi , hch@lst.de, kbusch@kernel.org, sagi@grimberg.me Cc: linux-nvme@lists.infradead.org, gost.dev@samsung.com, joshiiitr@gmail.com References: <20231018183003.41174-1-joshi.k@samsung.com> From: Jens Axboe In-Reply-To: <20231018183003.41174-1-joshi.k@samsung.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231018_114040_608153_A9710CF6 X-CRM114-Status: GOOD ( 10.87 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On 10/18/23 12:30 PM, Kanchan Joshi wrote: > Patch 1: Prep. Adds the meta-transfer ability in nvme-pci > Patch 2: Enables fine-granular passthrough with the change that i/o > commands can transfer the data only via SGL. > > Requirement: > - Prepared against block 6.6 tree. > - The patch in uring-passthrough failure handling is required to see the > submission failure (if any) > https://lore.kernel.org/linux-nvme/20231018135718.28820-1-joshi.k@samsung.com/ I didn't have time to follow the previous discussion, but what's the reasoning behind allowing it for SGL only? IIRC, we do have an inline vec for a small number of vecs, so presumably this would not hit alloc+free for each IO? But even so, I would imagine that SGL is slower than PRP? Do we know how much? -- Jens Axboe