From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754452AbbALSSN (ORCPT ); Mon, 12 Jan 2015 13:18:13 -0500 Received: from smtp02.citrix.com ([66.165.176.63]:30355 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753624AbbALSSL (ORCPT ); Mon, 12 Jan 2015 13:18:11 -0500 X-IronPort-AV: E=Sophos;i="5.07,745,1413244800"; d="scan'208";a="215607694" Date: Mon, 12 Jan 2015 18:09:33 +0000 From: Stefano Stabellini X-X-Sender: sstabellini@kaball.uk.xensource.com To: CC: , Stefano Stabellini , Konrad Rzeszutek Wilk , David Vrabel , , , Ian Campbell Subject: backport a4dba130891271084344c12537731542ec77cb85 to 3.16+ Message-ID: User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" X-DLP: MIA2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi all, I would like to request a backport of the following commit: commit a4dba130891271084344c12537731542ec77cb85 Author: Stefano Stabellini Date: Fri Nov 21 11:07:39 2014 +0000 xen/arm/arm64: introduce xen_arch_need_swiotlb to stable trees from 3.16 onward (3.16 included). The commit needs to be slightly modified because is_device_dma_coherent is not available on kernels < 3.19, so I just removed the call, thus assuming that the device is not coherent on arm (slower but safe): diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c -index ab700e1..28ebf3e 100644 +index b0e77de..f8a576b 100644 --- a/arch/arm/xen/mm.c +++ b/arch/arm/xen/mm.c -@@ -100,6 +100,13 @@ void __xen_dma_sync_single_for_device(struct device *hwdev, - __xen_dma_page_cpu_to_dev(hwdev, handle, size, dir); - } +@@ -16,6 +16,13 @@ + #include + #include +bool xen_arch_need_swiotlb(struct device *dev, + unsigned long pfn, + unsigned long mfn) +{ -+ return ((pfn != mfn) && !is_device_dma_coherent(dev)); ++ return (pfn != mfn); +} + int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order, The modified patch follows. --- xen/arm/arm64: introduce xen_arch_need_swiotlb From: Stefano Stabellini Introduce an arch specific function to find out whether a particular dma mapping operation needs to bounce on the swiotlb buffer. On ARM and ARM64, if the page involved is a foreign page and the device is not coherent, we need to bounce because at unmap time we cannot execute any required cache maintenance operations (we don't know how to find the pfn from the mfn). No change of behaviour for x86. Signed-off-by: Stefano Stabellini Reviewed-by: David Vrabel Reviewed-by: Catalin Marinas Acked-by: Ian Campbell Acked-by: Konrad Rzeszutek Wilk diff --git a/arch/arm/include/asm/xen/page.h b/arch/arm/include/asm/xen/page.h index 135c24a..68c739b 100644 --- a/arch/arm/include/asm/xen/page.h +++ b/arch/arm/include/asm/xen/page.h @@ -107,4 +107,8 @@ static inline bool set_phys_to_machine(unsigned long pfn, unsigned long mfn) #define xen_remap(cookie, size) ioremap_cache((cookie), (size)) #define xen_unmap(cookie) iounmap((cookie)) +bool xen_arch_need_swiotlb(struct device *dev, + unsigned long pfn, + unsigned long mfn); + #endif /* _ASM_ARM_XEN_PAGE_H */ diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c index b0e77de..f8a576b 100644 --- a/arch/arm/xen/mm.c +++ b/arch/arm/xen/mm.c @@ -16,6 +16,13 @@ #include #include +bool xen_arch_need_swiotlb(struct device *dev, + unsigned long pfn, + unsigned long mfn) +{ + return (pfn != mfn); +} + int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order, unsigned int address_bits, dma_addr_t *dma_handle) diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h index c949923..f58ef6c 100644 --- a/arch/x86/include/asm/xen/page.h +++ b/arch/x86/include/asm/xen/page.h @@ -236,4 +236,11 @@ void make_lowmem_page_readwrite(void *vaddr); #define xen_remap(cookie, size) ioremap((cookie), (size)); #define xen_unmap(cookie) iounmap((cookie)) +static inline bool xen_arch_need_swiotlb(struct device *dev, + unsigned long pfn, + unsigned long mfn) +{ + return false; +} + #endif /* _ASM_X86_XEN_PAGE_H */ diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c index ebd8f21..ac5d41b 100644 --- a/drivers/xen/swiotlb-xen.c +++ b/drivers/xen/swiotlb-xen.c @@ -399,7 +399,9 @@ dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page, * buffering it. */ if (dma_capable(dev, dev_addr, size) && - !range_straddles_page_boundary(phys, size) && !swiotlb_force) { + !range_straddles_page_boundary(phys, size) && + !xen_arch_need_swiotlb(dev, PFN_DOWN(phys), PFN_DOWN(dev_addr)) && + !swiotlb_force) { /* we are not interested in the dma_addr returned by * xen_dma_map_page, only in the potential cache flushes executed * by the function. */ @@ -557,6 +559,7 @@ xen_swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, dma_addr_t dev_addr = xen_phys_to_bus(paddr); if (swiotlb_force || + xen_arch_need_swiotlb(hwdev, PFN_DOWN(paddr), PFN_DOWN(dev_addr)) || !dma_capable(hwdev, dev_addr, sg->length) || range_straddles_page_boundary(paddr, sg->length)) { phys_addr_t map = swiotlb_tbl_map_single(hwdev,