| Message ID | 20250219220751.1276854-2-suzuki.poulose@arm.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | arm64: realm: Fix DMA address for devices | expand |
On 2025-02-19 10:07 pm, Suzuki K Poulose wrote: > phys_to_dma() sets the encryption bit on the translated DMA address. But > dma_to_phys() clears the encryption bit after it has been translated back > to the physical address, which could fail if the device uses DMA ranges. > > Hopefully, AMD SME doesn't use it. ...by which you mean we don't think any AMD systems are using the ACPI _DMA method to constrain physical DMA ranges, otherwise SME with dma-direct would presumably already be broken by this lookup going wrong. > Anyways, let us fix it, before cleanup > the infrastructure for supporting other architectures. Reviewed-by: Robin Murphy <robin.murphy@arm.com> > Reported-by: Aneesh Kumar K.V <aneesh.kumar@kernel.org> > Link: https://lkml.kernel.org/r/yq5amsen9stc.fsf@kernel.org > Cc: Will Deacon <will@kernel.org> > Cc: Jean-Philippe Brucker <jean-philippe@linaro.org> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Robin Murphy <robin.murphy@arm.com> > Cc: Steven Price <steven.price@arm.com> > Cc: Christoph Hellwig <hch@lst.de> > Cc: Tom Lendacky <thomas.lendacky@amd.com> > Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> > --- > include/linux/dma-direct.h | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h > index d7e30d4f7503..d20ecc24cb0f 100644 > --- a/include/linux/dma-direct.h > +++ b/include/linux/dma-direct.h > @@ -101,12 +101,13 @@ static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dma_addr) > { > phys_addr_t paddr; > > + dma_addr = __sme_clr(dma_addr); > if (dev->dma_range_map) > paddr = translate_dma_to_phys(dev, dma_addr); > else > paddr = dma_addr; > > - return __sme_clr(paddr); > + return paddr; > } > #endif /* !CONFIG_ARCH_HAS_PHYS_TO_DMA */ >
On 25/02/2025 11:25, Robin Murphy wrote: > On 2025-02-19 10:07 pm, Suzuki K Poulose wrote: >> phys_to_dma() sets the encryption bit on the translated DMA address. But >> dma_to_phys() clears the encryption bit after it has been translated back >> to the physical address, which could fail if the device uses DMA ranges. >> >> Hopefully, AMD SME doesn't use it. > > ...by which you mean we don't think any AMD systems are using the ACPI > _DMA method to constrain physical DMA ranges, otherwise SME with dma- > direct would presumably already be broken by this lookup going wrong. Yep, that AMD systems aren't using DMA ranges. > >> Anyways, let us fix it, before cleanup >> the infrastructure for supporting other architectures. > > Reviewed-by: Robin Murphy <robin.murphy@arm.com> Thanks Suzuki > >> Reported-by: Aneesh Kumar K.V <aneesh.kumar@kernel.org> >> Link: https://lkml.kernel.org/r/yq5amsen9stc.fsf@kernel.org >> Cc: Will Deacon <will@kernel.org> >> Cc: Jean-Philippe Brucker <jean-philippe@linaro.org> >> Cc: Catalin Marinas <catalin.marinas@arm.com> >> Cc: Robin Murphy <robin.murphy@arm.com> >> Cc: Steven Price <steven.price@arm.com> >> Cc: Christoph Hellwig <hch@lst.de> >> Cc: Tom Lendacky <thomas.lendacky@amd.com> >> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> >> --- >> include/linux/dma-direct.h | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h >> index d7e30d4f7503..d20ecc24cb0f 100644 >> --- a/include/linux/dma-direct.h >> +++ b/include/linux/dma-direct.h >> @@ -101,12 +101,13 @@ static inline phys_addr_t dma_to_phys(struct >> device *dev, dma_addr_t dma_addr) >> { >> phys_addr_t paddr; >> + dma_addr = __sme_clr(dma_addr); >> if (dev->dma_range_map) >> paddr = translate_dma_to_phys(dev, dma_addr); >> else >> paddr = dma_addr; >> - return __sme_clr(paddr); >> + return paddr; >> } >> #endif /* !CONFIG_ARCH_HAS_PHYS_TO_DMA */ >
On 2/19/25 16:07, Suzuki K Poulose wrote: > phys_to_dma() sets the encryption bit on the translated DMA address. But > dma_to_phys() clears the encryption bit after it has been translated back > to the physical address, which could fail if the device uses DMA ranges. > > Hopefully, AMD SME doesn't use it. Anyways, let us fix it, before cleanup > the infrastructure for supporting other architectures. I'm not aware of anything using DMA ranges on SME capable hardware. And as you stated, this would have failed if there was. Acked-by: Tom Lendacky <thomas.lendacky@amd.com> > > Reported-by: Aneesh Kumar K.V <aneesh.kumar@kernel.org> > Link: https://lkml.kernel.org/r/yq5amsen9stc.fsf@kernel.org > Cc: Will Deacon <will@kernel.org> > Cc: Jean-Philippe Brucker <jean-philippe@linaro.org> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Robin Murphy <robin.murphy@arm.com> > Cc: Steven Price <steven.price@arm.com> > Cc: Christoph Hellwig <hch@lst.de> > Cc: Tom Lendacky <thomas.lendacky@amd.com> > Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> > --- > include/linux/dma-direct.h | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h > index d7e30d4f7503..d20ecc24cb0f 100644 > --- a/include/linux/dma-direct.h > +++ b/include/linux/dma-direct.h > @@ -101,12 +101,13 @@ static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dma_addr) > { > phys_addr_t paddr; > > + dma_addr = __sme_clr(dma_addr); > if (dev->dma_range_map) > paddr = translate_dma_to_phys(dev, dma_addr); > else > paddr = dma_addr; > > - return __sme_clr(paddr); > + return paddr; > } > #endif /* !CONFIG_ARCH_HAS_PHYS_TO_DMA */ >
diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h index d7e30d4f7503..d20ecc24cb0f 100644 --- a/include/linux/dma-direct.h +++ b/include/linux/dma-direct.h @@ -101,12 +101,13 @@ static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dma_addr) { phys_addr_t paddr; + dma_addr = __sme_clr(dma_addr); if (dev->dma_range_map) paddr = translate_dma_to_phys(dev, dma_addr); else paddr = dma_addr; - return __sme_clr(paddr); + return paddr; } #endif /* !CONFIG_ARCH_HAS_PHYS_TO_DMA */
phys_to_dma() sets the encryption bit on the translated DMA address. But dma_to_phys() clears the encryption bit after it has been translated back to the physical address, which could fail if the device uses DMA ranges. Hopefully, AMD SME doesn't use it. Anyways, let us fix it, before cleanup the infrastructure for supporting other architectures. Reported-by: Aneesh Kumar K.V <aneesh.kumar@kernel.org> Link: https://lkml.kernel.org/r/yq5amsen9stc.fsf@kernel.org Cc: Will Deacon <will@kernel.org> Cc: Jean-Philippe Brucker <jean-philippe@linaro.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Robin Murphy <robin.murphy@arm.com> Cc: Steven Price <steven.price@arm.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> --- include/linux/dma-direct.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)