From patchwork Fri Aug 7 16:34:35 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Julien Grall X-Patchwork-Id: 6971411 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id B2A389F358 for ; Fri, 7 Aug 2015 16:38:32 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 8BDED20622 for ; Fri, 7 Aug 2015 16:38:31 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 4ED8E2061E for ; Fri, 7 Aug 2015 16:38:30 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZNkd1-0004R0-J4; Fri, 07 Aug 2015 16:36:19 +0000 Received: from smtp.citrix.com ([66.165.176.89]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZNkcw-0004II-PQ for linux-arm-kernel@lists.infradead.org; Fri, 07 Aug 2015 16:36:17 +0000 X-IronPort-AV: E=Sophos;i="5.15,630,1432598400"; d="scan'208";a="289165115" From: Julien Grall To: Subject: [PATCH v3 2/9] xen: Make clear that swiotlb and biomerge are dealing with DMA address Date: Fri, 7 Aug 2015 17:34:35 +0100 Message-ID: <1438965282-19103-3-git-send-email-julien.grall@citrix.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1438965282-19103-1-git-send-email-julien.grall@citrix.com> References: <1438965282-19103-1-git-send-email-julien.grall@citrix.com> MIME-Version: 1.0 X-DLP: MIA2 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150807_093615_200046_3EAE5A7E X-CRM114-Status: GOOD ( 21.06 ) X-Spam-Score: -7.0 (-------) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: x86@kernel.org, Russell King , ian.campbell@citrix.com, Konrad Rzeszutek Wilk , stefano.stabellini@eu.citrix.com, linux-kernel@vger.kernel.org, Julien Grall , Ingo Molnar , David Vrabel , "H. Peter Anvin" , Boris Ostrovsky , Thomas Gleixner , linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-4.3 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The swiotlb is required when programming a DMA address on ARM when a device is not protected by an IOMMU. In this case, the DMA address should always be equal to the machine address. For DOM0 memory, Xen ensure it by have an identity mapping between the guest address and host address. However, when mapping a foreign grant reference, the 1:1 model doesn't work. For ARM guest, most of the callers of pfn_to_mfn expects to get a GFN (Guest Frame Number), i.e a PFN (Page Frame Number) from the Linux point of view given that all ARM guest are auto-translated. Even though the name pfn_to_mfn is misleading, we need to ensure that those caller get a GFN and not by mistake a MFN. In pratical, I haven't seen error related to this but we should fix it for the sake of correctness. In order to fix the implementation of pfn_to_mfn on ARM in a follow-up patch, we have to introduce new helpers to return the DMA from a PFN and the invert. On x86, the new helpers will be an alias of pfn_to_mfn and mfn_to_pfn. The helpers will be used in swiotlb and xen_biovec_phys_mergeable. This is necessary in the latter because we have to ensure that the biovec code will not try to merge a biovec using foreign page and another using Linux memory. Lastly, the helper mfn_to_local_pfn has been renamed to bfn_to_local_pfn given that the only usage was in swiotlb. Signed-off-by: Julien Grall Reviewed-by: Stefano Stabellini --- Cc: Russell King Cc: Konrad Rzeszutek Wilk Cc: Boris Ostrovsky Cc: David Vrabel Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: x86@kernel.org Cc: linux-arm-kernel@lists.infradead.org Changes in v3: - Typoes in the commit message - Forgot to replace some dfn in bfn - Add Stefano's reviewed-by Changes in v2: - Use bfn (Bus Frame Number) rather than dfn to match the proposed terminology for pv-iommu hypercall. --- arch/arm/include/asm/xen/page.h | 23 +++++++++++++++++++++-- arch/arm/xen/mm.c | 4 ++-- arch/x86/include/asm/xen/page.h | 8 ++++++-- drivers/xen/biomerge.c | 6 +++--- drivers/xen/swiotlb-xen.c | 16 ++++++++-------- 5 files changed, 40 insertions(+), 17 deletions(-) diff --git a/arch/arm/include/asm/xen/page.h b/arch/arm/include/asm/xen/page.h index 98b1084..5f76a9e 100644 --- a/arch/arm/include/asm/xen/page.h +++ b/arch/arm/include/asm/xen/page.h @@ -52,7 +52,26 @@ static inline unsigned long mfn_to_pfn(unsigned long mfn) return mfn; } -#define mfn_to_local_pfn(mfn) mfn_to_pfn(mfn) +/* Pseudo-physical <-> BUS conversion */ +static inline unsigned long pfn_to_bfn(unsigned long pfn) +{ + unsigned long mfn; + + if (phys_to_mach.rb_node != NULL) { + mfn = __pfn_to_mfn(pfn); + if (mfn != INVALID_P2M_ENTRY) + return mfn; + } + + return pfn; +} + +static inline unsigned long bfn_to_pfn(unsigned long bfn) +{ + return bfn; +} + +#define bfn_to_local_pfn(bfn) bfn_to_pfn(bfn) /* VIRT <-> MACHINE conversion */ #define virt_to_mfn(v) (pfn_to_mfn(virt_to_pfn(v))) @@ -96,7 +115,7 @@ static inline bool set_phys_to_machine(unsigned long pfn, unsigned long mfn) bool xen_arch_need_swiotlb(struct device *dev, unsigned long pfn, - unsigned long mfn); + unsigned long bfn); unsigned long xen_get_swiotlb_free_pages(unsigned int order); #endif /* _ASM_ARM_XEN_PAGE_H */ diff --git a/arch/arm/xen/mm.c b/arch/arm/xen/mm.c index 03e75fe..6dd911d 100644 --- a/arch/arm/xen/mm.c +++ b/arch/arm/xen/mm.c @@ -139,9 +139,9 @@ void __xen_dma_sync_single_for_device(struct device *hwdev, bool xen_arch_need_swiotlb(struct device *dev, unsigned long pfn, - unsigned long mfn) + unsigned long bfn) { - return (!hypercall_cflush && (pfn != mfn) && !is_device_dma_coherent(dev)); + return (!hypercall_cflush && (pfn != bfn) && !is_device_dma_coherent(dev)); } int xen_create_contiguous_region(phys_addr_t pstart, unsigned int order, diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h index a3804fb..724bffb 100644 --- a/arch/x86/include/asm/xen/page.h +++ b/arch/x86/include/asm/xen/page.h @@ -176,6 +176,10 @@ static inline xpaddr_t machine_to_phys(xmaddr_t machine) return XPADDR(PFN_PHYS(mfn_to_pfn(PFN_DOWN(machine.maddr))) | offset); } +/* Pseudo-physical <-> Bus conversion */ +#define pfn_to_bfn(pfn) pfn_to_mfn(pfn) +#define bfn_to_pfn(bfn) mfn_to_pfn(bfn) + /* * We detect special mappings in one of two ways: * 1. If the MFN is an I/O page then Xen will set the m2p entry @@ -196,7 +200,7 @@ static inline xpaddr_t machine_to_phys(xmaddr_t machine) * require. In all the cases we care about, the FOREIGN_FRAME bit is * masked (e.g., pfn_to_mfn()) so behaviour there is correct. */ -static inline unsigned long mfn_to_local_pfn(unsigned long mfn) +static inline unsigned long bfn_to_local_pfn(unsigned long mfn) { unsigned long pfn; @@ -262,7 +266,7 @@ void make_lowmem_page_readwrite(void *vaddr); static inline bool xen_arch_need_swiotlb(struct device *dev, unsigned long pfn, - unsigned long mfn) + unsigned long bfn) { return false; } diff --git a/drivers/xen/biomerge.c b/drivers/xen/biomerge.c index 0edb91c..8ae2fc90 100644 --- a/drivers/xen/biomerge.c +++ b/drivers/xen/biomerge.c @@ -6,10 +6,10 @@ bool xen_biovec_phys_mergeable(const struct bio_vec *vec1, const struct bio_vec *vec2) { - unsigned long mfn1 = pfn_to_mfn(page_to_pfn(vec1->bv_page)); - unsigned long mfn2 = pfn_to_mfn(page_to_pfn(vec2->bv_page)); + unsigned long bfn1 = pfn_to_bfn(page_to_pfn(vec1->bv_page)); + unsigned long bfn2 = pfn_to_bfn(page_to_pfn(vec2->bv_page)); return __BIOVEC_PHYS_MERGEABLE(vec1, vec2) && - ((mfn1 == mfn2) || ((mfn1+1) == mfn2)); + ((bfn1 == bfn2) || ((bfn1+1) == bfn2)); } EXPORT_SYMBOL(xen_biovec_phys_mergeable); diff --git a/drivers/xen/swiotlb-xen.c b/drivers/xen/swiotlb-xen.c index 4c54932..d757a3e 100644 --- a/drivers/xen/swiotlb-xen.c +++ b/drivers/xen/swiotlb-xen.c @@ -82,8 +82,8 @@ static u64 start_dma_addr; */ static inline dma_addr_t xen_phys_to_bus(phys_addr_t paddr) { - unsigned long mfn = pfn_to_mfn(PFN_DOWN(paddr)); - dma_addr_t dma = (dma_addr_t)mfn << PAGE_SHIFT; + unsigned long bfn = pfn_to_bfn(PFN_DOWN(paddr)); + dma_addr_t dma = (dma_addr_t)bfn << PAGE_SHIFT; dma |= paddr & ~PAGE_MASK; @@ -92,7 +92,7 @@ static inline dma_addr_t xen_phys_to_bus(phys_addr_t paddr) static inline phys_addr_t xen_bus_to_phys(dma_addr_t baddr) { - unsigned long pfn = mfn_to_pfn(PFN_DOWN(baddr)); + unsigned long pfn = bfn_to_pfn(PFN_DOWN(baddr)); dma_addr_t dma = (dma_addr_t)pfn << PAGE_SHIFT; phys_addr_t paddr = dma; @@ -110,15 +110,15 @@ static int check_pages_physically_contiguous(unsigned long pfn, unsigned int offset, size_t length) { - unsigned long next_mfn; + unsigned long next_bfn; int i; int nr_pages; - next_mfn = pfn_to_mfn(pfn); + next_bfn = pfn_to_bfn(pfn); nr_pages = (offset + length + PAGE_SIZE-1) >> PAGE_SHIFT; for (i = 1; i < nr_pages; i++) { - if (pfn_to_mfn(++pfn) != ++next_mfn) + if (pfn_to_bfn(++pfn) != ++next_bfn) return 0; } return 1; @@ -138,8 +138,8 @@ static inline int range_straddles_page_boundary(phys_addr_t p, size_t size) static int is_xen_swiotlb_buffer(dma_addr_t dma_addr) { - unsigned long mfn = PFN_DOWN(dma_addr); - unsigned long pfn = mfn_to_local_pfn(mfn); + unsigned long bfn = PFN_DOWN(dma_addr); + unsigned long pfn = bfn_to_local_pfn(bfn); phys_addr_t paddr; /* If the address is outside our domain, it CAN