From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755162AbYD2Kh6 (ORCPT ); Tue, 29 Apr 2008 06:37:58 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754373AbYD2Khe (ORCPT ); Tue, 29 Apr 2008 06:37:34 -0400 Received: from bzq-179-150-194.static.bezeqint.net ([212.179.150.194]:10891 "EHLO il.qumranet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753679AbYD2Khc (ORCPT ); Tue, 29 Apr 2008 06:37:32 -0400 From: Amit Shah To: kvm-devel@lists.sourceforge.net Cc: virtualization@lists.linux-foundation.org, muli@il.ibm.com, BENAMI@il.ibm.com, gcosta@redhat.com, chrisw@redhat.com, dor.laor@qumranet.com, allen.m.kay@intel.com, avi@qumranet.com, linux-kernel@vger.kernel.org, Amit Shah Subject: [PATCH] x86 DMA: Handle devices assigned to the guest by the host Date: Tue, 29 Apr 2008 13:37:29 +0300 Message-Id: <1209465451-3758-2-git-send-email-amit.shah@qumranet.com> X-Mailer: git-send-email 1.5.5.1 In-Reply-To: <1209465451-3758-1-git-send-email-amit.shah@qumranet.com> References: <1209465451-3758-1-git-send-email-amit.shah@qumranet.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org dma_alloc_coherent() doesn't call dma_ops->alloc_coherent in case no IOMMU translations are necessary. However, if the device doing the DMA is a physical device assigned to the guest OS by the host, we need to map all the DMA addresses to the host machine addresses. This is done via hypercalls to the host. In KVM, with pci passthrough support, we can assign actual devices to the guest OS which need this functionality. Signed-off-by: Amit Shah --- arch/x86/kernel/pci-dma.c | 11 +++++++++++ include/asm-x86/dma-mapping.h | 2 ++ 2 files changed, 13 insertions(+), 0 deletions(-) diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c index 388b113..678cafb 100644 --- a/arch/x86/kernel/pci-dma.c +++ b/arch/x86/kernel/pci-dma.c @@ -443,6 +443,17 @@ dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_handle, memset(memory, 0, size); if (!mmu) { *dma_handle = bus; + if (unlikely(dma_ops->is_pv_device) && + unlikely(dma_ops->is_pv_device(dev, dev->bus_id))) { + void *r; + r = dma_ops->alloc_coherent(dev, size, + dma_handle, gfp); + if (r == NULL) { + free_pages((unsigned long)memory, + get_order(size)); + memory = NULL; + } + } return memory; } } diff --git a/include/asm-x86/dma-mapping.h b/include/asm-x86/dma-mapping.h index a1a4dc7..b9c6a39 100644 --- a/include/asm-x86/dma-mapping.h +++ b/include/asm-x86/dma-mapping.h @@ -55,6 +55,8 @@ struct dma_mapping_ops { int direction); int (*dma_supported)(struct device *hwdev, u64 mask); int is_phys; + /* Is this a physical device in a paravirtualized guest? */ + int (*is_pv_device)(struct device *hwdev, const char *name); }; extern const struct dma_mapping_ops *dma_ops; -- 1.5.4.3