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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 16CA5C3A5A3 for ; Tue, 27 Aug 2019 06:38:02 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (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 CFE1E206BB for ; Tue, 27 Aug 2019 06:38:01 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CFE1E206BB 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 mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id 89235FBC; Tue, 27 Aug 2019 06:38:01 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 16F58FA9 for ; Tue, 27 Aug 2019 06:38:00 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id E5F3B1FB for ; Tue, 27 Aug 2019 06:37:57 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 8625768AFE; Tue, 27 Aug 2019 08:37:54 +0200 (CEST) Date: Tue, 27 Aug 2019 08:37:54 +0200 From: Christoph Hellwig To: Stefano Stabellini , Konrad Rzeszutek Wilk Subject: Re: [PATCH 03/11] xen/arm: simplify dma_cache_maint Message-ID: <20190827063754.GA32045@lst.de> References: <20190826121944.515-1-hch@lst.de> <20190826121944.515-4-hch@lst.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190826121944.515-4-hch@lst.de> User-Agent: Mutt/1.5.17 (2007-11-01) Cc: xen-devel@lists.xenproject.org, iommu@lists.linux-foundation.org, x86@kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.12 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 Sender: iommu-bounces@lists.linux-foundation.org Errors-To: iommu-bounces@lists.linux-foundation.org And this was still buggy I think, it really needs some real Xen/Arm testing which I can't do. Hopefully better version below: -- >From 5ad4b6e291dbb49f65480c9b769414931cbd485a Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 24 Jul 2019 15:26:08 +0200 Subject: xen/arm: simplify dma_cache_maint Calculate the required operation in the caller, and pass it directly instead of recalculating it for each page, and use simple arithmetics to get from the physical address to Xen page size aligned chunks. Signed-off-by: Christoph Hellwig --- arch/arm/xen/mm.c | 61 ++++++++++++++++------------------------------- 1 file changed, 21 insertions(+), 40 deletions(-) diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c index 90574d89d0d4..2fde161733b0 100644 --- a/arch/arm/xen/mm.c +++ b/arch/arm/xen/mm.c @@ -35,64 +35,45 @@ unsigned long xen_get_swiotlb_free_pages(unsigned int order) return __get_free_pages(flags, order); } -enum dma_cache_op { - DMA_UNMAP, - DMA_MAP, -}; static bool hypercall_cflush = false; -/* functions called by SWIOTLB */ - -static void dma_cache_maint(dma_addr_t handle, unsigned long offset, - size_t size, enum dma_data_direction dir, enum dma_cache_op op) +/* buffers in highmem or foreign pages cannot cross page boundaries */ +static void dma_cache_maint(dma_addr_t handle, size_t size, u32 op) { struct gnttab_cache_flush cflush; - unsigned long xen_pfn; - size_t left = size; - xen_pfn = (handle >> XEN_PAGE_SHIFT) + offset / XEN_PAGE_SIZE; - offset %= XEN_PAGE_SIZE; + cflush.a.dev_bus_addr = handle & XEN_PAGE_MASK; + cflush.offset = xen_offset_in_page(handle); + cflush.op = op; do { - size_t len = left; - - /* buffers in highmem or foreign pages cannot cross page - * boundaries */ - if (len + offset > XEN_PAGE_SIZE) - len = XEN_PAGE_SIZE - offset; - - cflush.op = 0; - cflush.a.dev_bus_addr = xen_pfn << XEN_PAGE_SHIFT; - cflush.offset = offset; - cflush.length = len; - - if (op == DMA_UNMAP && dir != DMA_TO_DEVICE) - cflush.op = GNTTAB_CACHE_INVAL; - if (op == DMA_MAP) { - if (dir == DMA_FROM_DEVICE) - cflush.op = GNTTAB_CACHE_INVAL; - else - cflush.op = GNTTAB_CACHE_CLEAN; - } - if (cflush.op) - HYPERVISOR_grant_table_op(GNTTABOP_cache_flush, &cflush, 1); + if (size + cflush.offset > XEN_PAGE_SIZE) + cflush.length = XEN_PAGE_SIZE - cflush.offset; + else + cflush.length = size; + + HYPERVISOR_grant_table_op(GNTTABOP_cache_flush, &cflush, 1); - offset = 0; - xen_pfn++; - left -= len; - } while (left); + cflush.offset = 0; + cflush.a.dev_bus_addr += cflush.length; + size -= cflush.length; + } while (size); } static void __xen_dma_page_dev_to_cpu(struct device *hwdev, dma_addr_t handle, size_t size, enum dma_data_direction dir) { - dma_cache_maint(handle & PAGE_MASK, handle & ~PAGE_MASK, size, dir, DMA_UNMAP); + if (dir != DMA_TO_DEVICE) + dma_cache_maint(handle, size, GNTTAB_CACHE_INVAL); } static void __xen_dma_page_cpu_to_dev(struct device *hwdev, dma_addr_t handle, size_t size, enum dma_data_direction dir) { - dma_cache_maint(handle & PAGE_MASK, handle & ~PAGE_MASK, size, dir, DMA_MAP); + if (dir == DMA_FROM_DEVICE) + dma_cache_maint(handle, size, GNTTAB_CACHE_INVAL); + else + dma_cache_maint(handle, size, GNTTAB_CACHE_CLEAN); } void __xen_dma_map_page(struct device *hwdev, struct page *page, -- 2.20.1 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu