From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756191AbaELKQW (ORCPT ); Mon, 12 May 2014 06:16:22 -0400 Received: from smtp02.citrix.com ([66.165.176.63]:13437 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756078AbaELKQT (ORCPT ); Mon, 12 May 2014 06:16:19 -0400 X-IronPort-AV: E=Sophos;i="4.97,1034,1389744000"; d="scan'208";a="129289081" From: David Vrabel To: CC: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , , Greg Kroah-Hartman , , Konrad Rzeszutek Wilk , Boris Ostrovsky , David Vrabel Subject: [PATCH 2/2] x86,xen: correct dma_get_required_mask() for Xen PV guests Date: Mon, 12 May 2014 11:15:42 +0100 Message-ID: <1399889742-26165-3-git-send-email-david.vrabel@citrix.com> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1399889742-26165-1-git-send-email-david.vrabel@citrix.com> References: <1399889742-26165-1-git-send-email-david.vrabel@citrix.com> MIME-Version: 1.0 Content-Type: text/plain X-DLP: MIA2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On systems where DMA addresses and physical addresses are not 1:1 (such as Xen PV guests), the generic dma_get_required_mask() will not return the correct mask (since it uses max_pfn). Some device drivers (such as mptsas, mpt2sas) use dma_get_required_mask() to set device DMA masks to allow them to use only 32-bit DMA addresses in hardware structures. This results in unnecessary use of the SWIOTLB if DMA addresses are more than 32-bits, impacting performance significantly. Provide an arch-specific dma_get_required_mask() that defaults to the generic dma_get_required_mask_from_pfn(). Under Xen, the required DMA mask can then be set to always 64-bits. Signed-off-by: David Vrabel --- arch/x86/include/asm/device.h | 2 ++ arch/x86/kernel/pci-dma.c | 7 +++++++ arch/x86/xen/pci-swiotlb-xen.c | 1 + drivers/xen/swiotlb-xen.c | 7 +++++++ include/xen/swiotlb-xen.h | 4 ++++ 5 files changed, 21 insertions(+) diff --git a/arch/x86/include/asm/device.h b/arch/x86/include/asm/device.h index 03dd729..10bc628 100644 --- a/arch/x86/include/asm/device.h +++ b/arch/x86/include/asm/device.h @@ -13,4 +13,6 @@ struct dev_archdata { struct pdev_archdata { }; +#define ARCH_HAS_DMA_GET_REQUIRED_MASK + #endif /* _ASM_X86_DEVICE_H */ diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c index f7d0672..ad2c3e2 100644 --- a/arch/x86/kernel/pci-dma.c +++ b/arch/x86/kernel/pci-dma.c @@ -135,6 +135,13 @@ void dma_generic_free_coherent(struct device *dev, size_t size, void *vaddr, free_pages((unsigned long)vaddr, get_order(size)); } +u64 dma_get_required_mask(struct device *dev) +{ + if (dma_ops->get_required_mask) + return dma_ops->get_required_mask(dev); + return dma_get_required_mask_from_max_pfn(dev); +} + /* * See for the iommu kernel * parameter documentation. diff --git a/arch/x86/xen/pci-swiotlb-xen.c b/arch/x86/xen/pci-swiotlb-xen.c index 0e98e5d..a5d180a 100644 --- a/arch/x86/xen/pci-swiotlb-xen.c +++ b/arch/x86/xen/pci-swiotlb-xen.c @@ -31,6 +31,7 @@ static struct dma_map_ops xen_swiotlb_dma_ops = { .map_page = xen_swiotlb_map_page, .unmap_page = xen_swiotlb_unmap_page, .dma_supported = xen_swiotlb_dma_supported, + .get_required_mask = xen_swiotlb_get_required_mask, }; /* diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c index ebd8f21..798f62b 100644 --- a/drivers/xen/swiotlb-xen.c +++ b/drivers/xen/swiotlb-xen.c @@ -683,3 +683,10 @@ xen_swiotlb_set_dma_mask(struct device *dev, u64 dma_mask) return 0; } EXPORT_SYMBOL_GPL(xen_swiotlb_set_dma_mask); + +u64 +xen_swiotlb_get_required_mask(struct device *dev) +{ + return DMA_BIT_MASK(64); +} +EXPORT_SYMBOL_GPL(xen_swiotlb_get_required_mask); diff --git a/include/xen/swiotlb-xen.h b/include/xen/swiotlb-xen.h index 8b2eb93..6408888 100644 --- a/include/xen/swiotlb-xen.h +++ b/include/xen/swiotlb-xen.h @@ -58,4 +58,8 @@ xen_swiotlb_dma_supported(struct device *hwdev, u64 mask); extern int xen_swiotlb_set_dma_mask(struct device *dev, u64 dma_mask); + +extern u64 +xen_swiotlb_get_required_mask(struct device *dev); + #endif /* __LINUX_SWIOTLB_XEN_H */ -- 1.7.10.4