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a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1600094165; bh=MIiz3oSTFXEpNED0JGdyDe4iReP+I23HHhr/KZ789KI=; h=X-PGP-Universal:ARC-Seal:ARC-Message-Signature: ARC-Authentication-Results:Authentication-Results:Date:From:To:CC: Subject:Message-ID:References:Content-Type:Content-Disposition: In-Reply-To:X-ClientProxiedBy:MIME-Version: X-MS-Exchange-MessageSentRepresentingType:X-Originating-IP: X-MS-PublicTrafficType:X-MS-Office365-Filtering-Correlation-Id: X-MS-TrafficTypeDiagnostic:X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers:X-MS-Exchange-SenderADCheck: X-Microsoft-Antispam:X-Microsoft-Antispam-Message-Info: X-Forefront-Antispam-Report:X-MS-Exchange-AntiSpam-MessageData: X-MS-Exchange-CrossTenant-Network-Message-Id: X-MS-Exchange-CrossTenant-AuthSource: X-MS-Exchange-CrossTenant-AuthAs: X-MS-Exchange-CrossTenant-OriginalArrivalTime: X-MS-Exchange-CrossTenant-FromEntityHeader: X-MS-Exchange-CrossTenant-Id:X-MS-Exchange-CrossTenant-MailboxType: X-MS-Exchange-CrossTenant-UserPrincipalName: X-MS-Exchange-Transport-CrossTenantHeadersStamped:X-OriginatorOrg; b=ckG+UfN4+OwTmM/84OL+PNQ37QbyXpZidAQHHwRsYFhlUGhl2s1ivmwBmzvmUn1Vl sSS0D1edSUniADu4+eUxex8BbVRFdpJ44uzvDenuLNBqQyLVvn6IPJ5TxfW9JQezgD V37hYaMCzs2B01mL3SOT1JYSdbp4vqka7NFyHrgm0LoQurCeQ0fO4XIGiotWN0U+xr QHgOuZqdSTxPl/oTeUzePcsNfoKh4vSHY52iMPXIUHD9TF63dMNyjINh3gKHn3vJkP bzTn//PombRQC2JXt+q6XMqBq/1QdqlCdNAYPU9MGsS1/j+ihKMXKhusryZz2Gu5UQ vAhsAvFWMbhFA== Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Mon, Sep 14, 2020 at 02:24:06PM +0000, Clint Sbisa wrote: > On Mon, Sep 14, 2020 at 11:17:26AM -0300, Jason Gunthorpe wrote: > > On Fri, Sep 11, 2020 at 09:42:25PM +0000, Clint Sbisa wrote: > > > > > There's no DMA involved with this BAR-- the driver writes a portion of the > > > packet contents in addition to the descriptors, which generally increases the > > > number of TLPs if write-combine isn't used. Furthermore, this BAR is only used > > > for writes and never for reads. > > > > You use DPDK without DMA? How does receive work? > > That was not worded well. DMA is used, but the first X bytes of the packet are > written directly to this BAR instead of being DMA'd-- the rest of the data is > DMA'd. which is back to my original question, how do you do DMA using /sys/xx/resources? Why not use VFIO like everything else? Jason