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Message-ID: <5d797c06-401d-62b1-f144-ea6e9a5144dd@arm.com>
Date: Thu, 10 Sep 2020 14:26:03 +0100
From: Robin Murphy <robin.murphy@....com>
To: Christoph Hellwig <hch@....de>, Tony Luck <tony.luck@...el.com>,
Fenghua Yu <fenghua.yu@...el.com>,
Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
iommu@...ts.linux-foundation.org
Cc: Tomasz Figa <tfiga@...omium.org>, Joerg Roedel <joro@...tes.org>,
linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-ia64@...r.kernel.org, linux-mips@...r.kernel.org
Subject: Re: [PATCH 09/12] dma-direct: remove __dma_to_phys
On 2020-09-08 17:47, Christoph Hellwig wrote:
> There is no harm in just always clearing the SME encryption bit, while
> significantly simplifying the interface.
After a 10-minute diversion into "but hang on, force_dma_unencrypted()
is meaningful on PPC and S390 too..." before realising that it all does
just come back to __sme_clr(), which is indeed a no-op for everyone
other than AMD, any simplification of this mess is indeed welcome :)
Unless I've massively misunderstood how SME is supposed to work,
Reviewed-by: Robin Murphy <robin.murphy@....com>
> Signed-off-by: Christoph Hellwig <hch@....de>
> ---
> arch/arm/include/asm/dma-direct.h | 2 +-
> arch/mips/bmips/dma.c | 2 +-
> arch/mips/cavium-octeon/dma-octeon.c | 2 +-
> arch/mips/include/asm/dma-direct.h | 2 +-
> arch/mips/loongson2ef/fuloong-2e/dma.c | 2 +-
> arch/mips/loongson2ef/lemote-2f/dma.c | 2 +-
> arch/mips/loongson64/dma.c | 2 +-
> arch/mips/pci/pci-ar2315.c | 2 +-
> arch/mips/pci/pci-xtalk-bridge.c | 2 +-
> arch/mips/sgi-ip32/ip32-dma.c | 2 +-
> arch/powerpc/include/asm/dma-direct.h | 2 +-
> include/linux/dma-direct.h | 14 +++++---------
> kernel/dma/direct.c | 6 +-----
> 13 files changed, 17 insertions(+), 25 deletions(-)
>
> diff --git a/arch/arm/include/asm/dma-direct.h b/arch/arm/include/asm/dma-direct.h
> index 7c3001a6a775bf..a8cee87a93e8ab 100644
> --- a/arch/arm/include/asm/dma-direct.h
> +++ b/arch/arm/include/asm/dma-direct.h
> @@ -8,7 +8,7 @@ static inline dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
> return pfn_to_dma(dev, __phys_to_pfn(paddr)) + offset;
> }
>
> -static inline phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t dev_addr)
> +static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dev_addr)
> {
> unsigned int offset = dev_addr & ~PAGE_MASK;
> return __pfn_to_phys(dma_to_pfn(dev, dev_addr)) + offset;
> diff --git a/arch/mips/bmips/dma.c b/arch/mips/bmips/dma.c
> index df56bf4179e347..ba2a5d33dfd3fa 100644
> --- a/arch/mips/bmips/dma.c
> +++ b/arch/mips/bmips/dma.c
> @@ -52,7 +52,7 @@ dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t pa)
> return pa;
> }
>
> -phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t dma_addr)
> +phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dma_addr)
> {
> struct bmips_dma_range *r;
>
> diff --git a/arch/mips/cavium-octeon/dma-octeon.c b/arch/mips/cavium-octeon/dma-octeon.c
> index 14ea680d180e07..388b13ba2558c2 100644
> --- a/arch/mips/cavium-octeon/dma-octeon.c
> +++ b/arch/mips/cavium-octeon/dma-octeon.c
> @@ -177,7 +177,7 @@ dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
> return paddr;
> }
>
> -phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t daddr)
> +phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr)
> {
> #ifdef CONFIG_PCI
> if (dev && dev_is_pci(dev))
> diff --git a/arch/mips/include/asm/dma-direct.h b/arch/mips/include/asm/dma-direct.h
> index 14e352651ce946..8e178651c638c2 100644
> --- a/arch/mips/include/asm/dma-direct.h
> +++ b/arch/mips/include/asm/dma-direct.h
> @@ -3,6 +3,6 @@
> #define _MIPS_DMA_DIRECT_H 1
>
> dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr);
> -phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t daddr);
> +phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr);
>
> #endif /* _MIPS_DMA_DIRECT_H */
> diff --git a/arch/mips/loongson2ef/fuloong-2e/dma.c b/arch/mips/loongson2ef/fuloong-2e/dma.c
> index e122292bf6660a..83fadeb3fd7d56 100644
> --- a/arch/mips/loongson2ef/fuloong-2e/dma.c
> +++ b/arch/mips/loongson2ef/fuloong-2e/dma.c
> @@ -6,7 +6,7 @@ dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
> return paddr | 0x80000000;
> }
>
> -phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t dma_addr)
> +phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dma_addr)
> {
> return dma_addr & 0x7fffffff;
> }
> diff --git a/arch/mips/loongson2ef/lemote-2f/dma.c b/arch/mips/loongson2ef/lemote-2f/dma.c
> index abf0e39d7e4696..302b43a14eee74 100644
> --- a/arch/mips/loongson2ef/lemote-2f/dma.c
> +++ b/arch/mips/loongson2ef/lemote-2f/dma.c
> @@ -6,7 +6,7 @@ dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
> return paddr | 0x80000000;
> }
>
> -phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t dma_addr)
> +phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dma_addr)
> {
> if (dma_addr > 0x8fffffff)
> return dma_addr;
> diff --git a/arch/mips/loongson64/dma.c b/arch/mips/loongson64/dma.c
> index dbfe6e82fddd1c..b3dc5d0bd2b113 100644
> --- a/arch/mips/loongson64/dma.c
> +++ b/arch/mips/loongson64/dma.c
> @@ -13,7 +13,7 @@ dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
> return ((nid << 44) ^ paddr) | (nid << node_id_offset);
> }
>
> -phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t daddr)
> +phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr)
> {
> /* We extract 2bit node id (bit 44~47, only bit 44~45 used now) from
> * Loongson-3's 48bit address space and embed it into 40bit */
> diff --git a/arch/mips/pci/pci-ar2315.c b/arch/mips/pci/pci-ar2315.c
> index 490953f515282a..d88395684f487d 100644
> --- a/arch/mips/pci/pci-ar2315.c
> +++ b/arch/mips/pci/pci-ar2315.c
> @@ -175,7 +175,7 @@ dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
> return paddr + ar2315_dev_offset(dev);
> }
>
> -phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t dma_addr)
> +phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dma_addr)
> {
> return dma_addr - ar2315_dev_offset(dev);
> }
> diff --git a/arch/mips/pci/pci-xtalk-bridge.c b/arch/mips/pci/pci-xtalk-bridge.c
> index 9b3cc775c55e05..f1b37f32b55395 100644
> --- a/arch/mips/pci/pci-xtalk-bridge.c
> +++ b/arch/mips/pci/pci-xtalk-bridge.c
> @@ -33,7 +33,7 @@ dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
> return bc->baddr + paddr;
> }
>
> -phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t dma_addr)
> +phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dma_addr)
> {
> return dma_addr & ~(0xffUL << 56);
> }
> diff --git a/arch/mips/sgi-ip32/ip32-dma.c b/arch/mips/sgi-ip32/ip32-dma.c
> index fa7b17cb53853e..160317294d97a9 100644
> --- a/arch/mips/sgi-ip32/ip32-dma.c
> +++ b/arch/mips/sgi-ip32/ip32-dma.c
> @@ -27,7 +27,7 @@ dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
> return dma_addr;
> }
>
> -phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t dma_addr)
> +phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dma_addr)
> {
> phys_addr_t paddr = dma_addr & RAM_OFFSET_MASK;
>
> diff --git a/arch/powerpc/include/asm/dma-direct.h b/arch/powerpc/include/asm/dma-direct.h
> index abc154d784b078..95b09313d2a4cf 100644
> --- a/arch/powerpc/include/asm/dma-direct.h
> +++ b/arch/powerpc/include/asm/dma-direct.h
> @@ -7,7 +7,7 @@ static inline dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
> return paddr + dev->archdata.dma_offset;
> }
>
> -static inline phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t daddr)
> +static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr)
> {
> return daddr - dev->archdata.dma_offset;
> }
> diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h
> index 20eceb2e4f91f8..f00e262ab6b154 100644
> --- a/include/linux/dma-direct.h
> +++ b/include/linux/dma-direct.h
> @@ -24,11 +24,12 @@ static inline dma_addr_t __phys_to_dma(struct device *dev, phys_addr_t paddr)
> return dev_addr - ((dma_addr_t)dev->dma_pfn_offset << PAGE_SHIFT);
> }
>
> -static inline phys_addr_t __dma_to_phys(struct device *dev, dma_addr_t dev_addr)
> +static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dev_addr)
> {
> - phys_addr_t paddr = (phys_addr_t)dev_addr;
> + phys_addr_t paddr = (phys_addr_t)dev_addr +
> + ((phys_addr_t)dev->dma_pfn_offset << PAGE_SHIFT);
>
> - return paddr + ((phys_addr_t)dev->dma_pfn_offset << PAGE_SHIFT);
> + return __sme_clr(paddr);
> }
> #endif /* !CONFIG_ARCH_HAS_PHYS_TO_DMA */
>
> @@ -44,7 +45,7 @@ static inline bool force_dma_unencrypted(struct device *dev)
> /*
> * If memory encryption is supported, phys_to_dma will set the memory encryption
> * bit in the DMA address, and dma_to_phys will clear it. The raw __phys_to_dma
> - * and __dma_to_phys versions should only be used on non-encrypted memory for
> + * version should only be used on non-encrypted memory for
> * special occasions like DMA coherent buffers.
> */
> static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
> @@ -52,11 +53,6 @@ static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
> return __sme_set(__phys_to_dma(dev, paddr));
> }
>
> -static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr)
> -{
> - return __sme_clr(__dma_to_phys(dev, daddr));
> -}
> -
> static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size,
> bool is_ram)
> {
> diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
> index 57a6e7d7cf8f16..bfb479c8a370fa 100644
> --- a/kernel/dma/direct.c
> +++ b/kernel/dma/direct.c
> @@ -48,11 +48,6 @@ static gfp_t dma_direct_optimal_gfp_mask(struct device *dev, u64 dma_mask,
> {
> u64 dma_limit = min_not_zero(dma_mask, dev->bus_dma_limit);
>
> - if (force_dma_unencrypted(dev))
> - *phys_limit = __dma_to_phys(dev, dma_limit);
> - else
> - *phys_limit = dma_to_phys(dev, dma_limit);
> -
> /*
> * Optimistically try the zone that the physical address mask falls
> * into first. If that returns memory that isn't actually addressable
> @@ -61,6 +56,7 @@ static gfp_t dma_direct_optimal_gfp_mask(struct device *dev, u64 dma_mask,
> * Note that GFP_DMA32 and GFP_DMA are no ops without the corresponding
> * zones.
> */
> + *phys_limit = dma_to_phys(dev, dma_limit);
> if (*phys_limit <= DMA_BIT_MASK(zone_dma_bits))
> return GFP_DMA;
> if (*phys_limit <= DMA_BIT_MASK(32))
>
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