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 X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CB040C49EA3 for ; Mon, 14 Jun 2021 15:33:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B1B7E6120E for ; Mon, 14 Jun 2021 15:33:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233740AbhFNPfv (ORCPT ); Mon, 14 Jun 2021 11:35:51 -0400 Received: from verein.lst.de ([213.95.11.211]:45003 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232985AbhFNPfp (ORCPT ); Mon, 14 Jun 2021 11:35:45 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id 4E32868AFE; Mon, 14 Jun 2021 17:33:39 +0200 (CEST) Date: Mon, 14 Jun 2021 17:33:39 +0200 From: Christoph Hellwig To: Tianyu Lan Cc: Christoph Hellwig , kys@microsoft.com, haiyangz@microsoft.com, sthemmin@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com, arnd@arndb.de, dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, akpm@linux-foundation.org, kirill.shutemov@linux.intel.com, rppt@kernel.org, hannes@cmpxchg.org, cai@lca.pw, krish.sadhukhan@oracle.com, saravanand@fb.com, Tianyu.Lan@microsoft.com, konrad.wilk@oracle.com, m.szyprowski@samsung.com, robin.murphy@arm.com, boris.ostrovsky@oracle.com, jgross@suse.com, sstabellini@kernel.org, joro@8bytes.org, will@kernel.org, xen-devel@lists.xenproject.org, davem@davemloft.net, kuba@kernel.org, jejb@linux.ibm.com, martin.petersen@oracle.com, iommu@lists.linux-foundation.org, linux-arch@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, netdev@vger.kernel.org, vkuznets@redhat.com, thomas.lendacky@amd.com, brijesh.singh@amd.com, sunilmut@microsoft.com Subject: Re: [RFC PATCH V3 10/11] HV/Netvsc: Add Isolation VM support for netvsc driver Message-ID: <20210614153339.GB1741@lst.de> References: <20210530150628.2063957-1-ltykernel@gmail.com> <20210530150628.2063957-11-ltykernel@gmail.com> <20210607065007.GE24478@lst.de> <279cb4bf-c5b6-6db9-0f1e-9238e902c8f2@gmail.com> <20210614070903.GA29976@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 14, 2021 at 10:04:06PM +0800, Tianyu Lan wrote: > The pages in the hv_page_buffer array here are in the kernel linear > mapping. The packet sent to host will contain an array which contains > transaction data. In the isolation VM, data in the these pages needs to be > copied to bounce buffer and so call dma_map_single() here to map these data > pages with bounce buffer. The vmbus has ring buffer where the send/receive > packets are copied to/from. The ring buffer has been remapped to the extra > space above shared gpa boundary/vTom during probing Netvsc driver and so > not call dma map function for vmbus ring > buffer. So why do we have all that PFN magic instead of using struct page or the usual kernel I/O buffers that contain a page pointer? 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 X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 32E65C2B9F4 for ; Mon, 14 Jun 2021 15:33:46 +0000 (UTC) Received: from smtp4.osuosl.org (smtp4.osuosl.org [140.211.166.137]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id BCA9761352 for ; Mon, 14 Jun 2021 15:33:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BCA9761352 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id 8C6C440233; Mon, 14 Jun 2021 15:33:45 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id fmfwx7TgDhxI; Mon, 14 Jun 2021 15:33:44 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp4.osuosl.org (Postfix) with ESMTPS id 69C46401CC; Mon, 14 Jun 2021 15:33:44 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 5193FC000D; Mon, 14 Jun 2021 15:33:44 +0000 (UTC) Received: from smtp2.osuosl.org (smtp2.osuosl.org [140.211.166.133]) by lists.linuxfoundation.org (Postfix) with ESMTP id 56C57C000B for ; Mon, 14 Jun 2021 15:33:43 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id 41A6140379 for ; Mon, 14 Jun 2021 15:33:43 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Rgwcyyn8j9rC for ; Mon, 14 Jun 2021 15:33:42 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.8.0 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by smtp2.osuosl.org (Postfix) with ESMTPS id 9C7E24036A for ; Mon, 14 Jun 2021 15:33:42 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 4E32868AFE; Mon, 14 Jun 2021 17:33:39 +0200 (CEST) Date: Mon, 14 Jun 2021 17:33:39 +0200 From: Christoph Hellwig To: Tianyu Lan Subject: Re: [RFC PATCH V3 10/11] HV/Netvsc: Add Isolation VM support for netvsc driver Message-ID: <20210614153339.GB1741@lst.de> References: <20210530150628.2063957-1-ltykernel@gmail.com> <20210530150628.2063957-11-ltykernel@gmail.com> <20210607065007.GE24478@lst.de> <279cb4bf-c5b6-6db9-0f1e-9238e902c8f2@gmail.com> <20210614070903.GA29976@lst.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Cc: linux-hyperv@vger.kernel.org, brijesh.singh@amd.com, thomas.lendacky@amd.com, peterz@infradead.org, dave.hansen@linux.intel.com, hpa@zytor.com, kys@microsoft.com, will@kernel.org, Christoph Hellwig , linux-arch@vger.kernel.org, wei.liu@kernel.org, sstabellini@kernel.org, sthemmin@microsoft.com, linux-scsi@vger.kernel.org, x86@kernel.org, decui@microsoft.com, mingo@redhat.com, xen-devel@lists.xenproject.org, jejb@linux.ibm.com, jgross@suse.com, Tianyu.Lan@microsoft.com, arnd@arndb.de, konrad.wilk@oracle.com, haiyangz@microsoft.com, kuba@kernel.org, bp@alien8.de, luto@kernel.org, krish.sadhukhan@oracle.com, tglx@linutronix.de, vkuznets@redhat.com, boris.ostrovsky@oracle.com, martin.petersen@oracle.com, saravanand@fb.com, netdev@vger.kernel.org, sunilmut@microsoft.com, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, kirill.shutemov@linux.intel.com, hannes@cmpxchg.org, cai@lca.pw, akpm@linux-foundation.org, robin.murphy@arm.com, davem@davemloft.net, rppt@kernel.org X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On Mon, Jun 14, 2021 at 10:04:06PM +0800, Tianyu Lan wrote: > The pages in the hv_page_buffer array here are in the kernel linear > mapping. The packet sent to host will contain an array which contains > transaction data. In the isolation VM, data in the these pages needs to be > copied to bounce buffer and so call dma_map_single() here to map these data > pages with bounce buffer. The vmbus has ring buffer where the send/receive > packets are copied to/from. The ring buffer has been remapped to the extra > space above shared gpa boundary/vTom during probing Netvsc driver and so > not call dma map function for vmbus ring > buffer. So why do we have all that PFN magic instead of using struct page or the usual kernel I/O buffers that contain a page pointer? _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu