From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ram Pai Subject: [PATCH 1/2] dma-mapping: Add dma_addr_is_phys_addr() Date: Fri, 11 Oct 2019 18:25:18 -0700 Message-ID: <1570843519-8696-2-git-send-email-linuxram__42609.1452407249$1570844096$gmane$org@us.ibm.com> References: <1570843519-8696-1-git-send-email-linuxram@us.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1570843519-8696-1-git-send-email-linuxram@us.ibm.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: linux-kernel@vger.kernel.org Cc: andmike@us.ibm.com, sukadev@linux.vnet.ibm.com, b.zolnierkie@samsung.com, benh@kernel.crashing.org, aik@linux.ibm.com, linuxram@us.ibm.com, virtualization@lists.linux-foundation.org, paulus@ozlabs.org, iommu@lists.linux-foundation.org, paul.burton@mips.com, mpe@ellerman.id.au, robin.murphy@arm.com, m.szyprowski@samsung.com, linuxppc-dev@lists.ozlabs.org, hch@lst.de, david@gibson.dropbear.id.au List-Id: virtualization@lists.linuxfoundation.org From: Thiago Jung Bauermann In order to safely use the DMA API, virtio needs to know whether DMA addresses are in fact physical addresses and for that purpose, dma_addr_is_phys_addr() is introduced. cc: Benjamin Herrenschmidt cc: David Gibson cc: Michael Ellerman cc: Paul Mackerras cc: Michael Roth cc: Alexey Kardashevskiy cc: Paul Burton cc: Robin Murphy cc: Bartlomiej Zolnierkiewicz cc: Marek Szyprowski cc: Christoph Hellwig Suggested-by: Michael S. Tsirkin Signed-off-by: Ram Pai Signed-off-by: Thiago Jung Bauermann --- arch/powerpc/include/asm/dma-mapping.h | 21 +++++++++++++++++++++ arch/powerpc/platforms/pseries/Kconfig | 1 + include/linux/dma-mapping.h | 20 ++++++++++++++++++++ kernel/dma/Kconfig | 3 +++ 4 files changed, 45 insertions(+) diff --git a/arch/powerpc/include/asm/dma-mapping.h b/arch/powerpc/include/asm/dma-mapping.h index 565d6f7..f92c0a4b 100644 --- a/arch/powerpc/include/asm/dma-mapping.h +++ b/arch/powerpc/include/asm/dma-mapping.h @@ -5,6 +5,8 @@ #ifndef _ASM_DMA_MAPPING_H #define _ASM_DMA_MAPPING_H +#include + static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus) { /* We don't handle the NULL dev case for ISA for now. We could @@ -15,4 +17,23 @@ static inline const struct dma_map_ops *get_arch_dma_ops(struct bus_type *bus) return NULL; } +#ifdef CONFIG_ARCH_HAS_DMA_ADDR_IS_PHYS_ADDR +/** + * dma_addr_is_phys_addr - check whether a device DMA address is a physical + * address + * @dev: device to check + * + * Returns %true if any DMA address for this device happens to also be a valid + * physical address (not necessarily of the same page). + */ +static inline bool dma_addr_is_phys_addr(struct device *dev) +{ + /* + * Secure guests always use the SWIOTLB, therefore DMA addresses are + * actually the physical address of the bounce buffer. + */ + return is_secure_guest(); +} +#endif + #endif /* _ASM_DMA_MAPPING_H */ diff --git a/arch/powerpc/platforms/pseries/Kconfig b/arch/powerpc/platforms/pseries/Kconfig index 9e35cdd..0108150 100644 --- a/arch/powerpc/platforms/pseries/Kconfig +++ b/arch/powerpc/platforms/pseries/Kconfig @@ -152,6 +152,7 @@ config PPC_SVM select SWIOTLB select ARCH_HAS_MEM_ENCRYPT select ARCH_HAS_FORCE_DMA_UNENCRYPTED + select ARCH_HAS_DMA_ADDR_IS_PHYS_ADDR help There are certain POWER platforms which support secure guests using the Protected Execution Facility, with the help of an Ultravisor diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index f7d1eea..6df5664 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -693,6 +693,26 @@ static inline bool dma_addressing_limited(struct device *dev) dma_get_required_mask(dev); } +#ifndef CONFIG_ARCH_HAS_DMA_ADDR_IS_PHYS_ADDR +/** + * dma_addr_is_phys_addr - check whether a device DMA address is a physical + * address + * @dev: device to check + * + * Returns %true if any DMA address for this device happens to also be a valid + * physical address (not necessarily of the same page). + */ +static inline bool dma_addr_is_phys_addr(struct device *dev) +{ + /* + * Except in very specific setups, DMA addresses exist in a different + * address space from CPU physical addresses and cannot be directly used + * to reference system memory. + */ + return false; +} +#endif + #ifdef CONFIG_ARCH_HAS_SETUP_DMA_OPS void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size, const struct iommu_ops *iommu, bool coherent); diff --git a/kernel/dma/Kconfig b/kernel/dma/Kconfig index 9decbba..6209b46 100644 --- a/kernel/dma/Kconfig +++ b/kernel/dma/Kconfig @@ -51,6 +51,9 @@ config ARCH_HAS_DMA_MMAP_PGPROT config ARCH_HAS_FORCE_DMA_UNENCRYPTED bool +config ARCH_HAS_DMA_ADDR_IS_PHYS_ADDR + bool + config DMA_NONCOHERENT_CACHE_SYNC bool -- 1.8.3.1