RE: [PATCH V7 5/8] arm64/dma-mapping: Implement DMA_ATTR_PRIVILEGED

[Sricharan]

Hi,

>
>On 13/12/16 14:38, Sricharan wrote:
>> Hi Robin,
>>
>>> -----Original Message-----
>>> From: linux-arm-kernel [mailto:linux-arm-kernel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Robin Murphy
>>> Sent: Tuesday, December 13, 2016 7:33 PM
>>> To: Sricharan R <sricharan@xxxxxxxxxxxxxx>; jcrouse@xxxxxxxxxxxxxx; pdaly@xxxxxxxxxxxxxx; jgebben@xxxxxxxxxxxxxx;
>>> joro@xxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; pratikp@xxxxxxxxxxxxxx; iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx;
>tzeng@xxxxxxxxxxxxxx;
>>> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; will.deacon@xxxxxxx; mitchelh@xxxxxxxxxxxxxx; vinod.koul@xxxxxxxxx
>>> Cc: dan.j.williams@xxxxxxxxx
>>> Subject: Re: [PATCH V7 5/8] arm64/dma-mapping: Implement DMA_ATTR_PRIVILEGED
>>>
>>> On 12/12/16 18:38, Sricharan R wrote:
>>>> From: Mitchel Humpherys <mitchelh@xxxxxxxxxxxxxx>
>>>>
>>>> The newly added DMA_ATTR_PRIVILEGED is useful for creating mappings that
>>>> are only accessible to privileged DMA engines.  Implement it in
>>>> dma-iommu.c so that the ARM64 DMA IOMMU mapper can make use of it.
>>>>
>>>> Reviewed-by: Robin Murphy <robin.murphy@xxxxxxx>
>>>> Tested-by: Robin Murphy <robin.murphy@xxxxxxx>
>>>> Acked-by: Will Deacon <will.deacon@xxxxxxx>
>>>> Signed-off-by: Mitchel Humpherys <mitchelh@xxxxxxxxxxxxxx>
>>>> ---
>>>>  arch/arm64/mm/dma-mapping.c |  6 +++---
>>>>  drivers/iommu/dma-iommu.c   | 10 ++++++++--
>>>>  include/linux/dma-iommu.h   |  3 ++-
>>>>  3 files changed, 13 insertions(+), 6 deletions(-)
>>>>
>>>> diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
>>>> index 401f79a..ae76ead 100644
>>>> --- a/arch/arm64/mm/dma-mapping.c
>>>> +++ b/arch/arm64/mm/dma-mapping.c
>>>> @@ -557,7 +557,7 @@ static void *__iommu_alloc_attrs(struct device *dev, size_t size,
>>>>  				 unsigned long attrs)
>>>>  {
>>>>  	bool coherent = is_device_dma_coherent(dev);
>>>> -	int ioprot = dma_direction_to_prot(DMA_BIDIRECTIONAL, coherent);
>>>> +	int ioprot = dma_info_to_prot(DMA_BIDIRECTIONAL, coherent, attrs);
>>>>  	size_t iosize = size;
>>>>  	void *addr;
>>>>
>>>> @@ -711,7 +711,7 @@ static dma_addr_t __iommu_map_page(struct device *dev, struct page *page,
>>>>  				   unsigned long attrs)
>>>>  {
>>>>  	bool coherent = is_device_dma_coherent(dev);
>>>> -	int prot = dma_direction_to_prot(dir, coherent);
>>>> +	int prot = dma_info_to_prot(dir, coherent, attrs);
>>>>  	dma_addr_t dev_addr = iommu_dma_map_page(dev, page, offset, size, prot);
>>>>
>>>>  	if (!iommu_dma_mapping_error(dev, dev_addr) &&
>>>> @@ -769,7 +769,7 @@ static int __iommu_map_sg_attrs(struct device *dev, struct scatterlist *sgl,
>>>>  		__iommu_sync_sg_for_device(dev, sgl, nelems, dir);
>>>>
>>>>  	return iommu_dma_map_sg(dev, sgl, nelems,
>>>> -			dma_direction_to_prot(dir, coherent));
>>>> +				dma_info_to_prot(dir, coherent, attrs));
>>>>  }
>>>>
>>>>  static void __iommu_unmap_sg_attrs(struct device *dev,
>>>> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
>>>> index d2a7a46..756d5e0 100644
>>>> --- a/drivers/iommu/dma-iommu.c
>>>> +++ b/drivers/iommu/dma-iommu.c
>>>> @@ -182,16 +182,22 @@ int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
>>>>  EXPORT_SYMBOL(iommu_dma_init_domain);
>>>>
>>>>  /**
>>>> - * dma_direction_to_prot - Translate DMA API directions to IOMMU API page flags
>>>> + * dma_info_to_prot - Translate DMA API directions and attributes to IOMMU API
>>>> + *                    page flags.
>>>>   * @dir: Direction of DMA transfer
>>>>   * @coherent: Is the DMA master cache-coherent?
>>>> + * @attrs: DMA attributes for the mapping
>>>>   *
>>>>   * Return: corresponding IOMMU API page protection flags
>>>>   */
>>>> -int dma_direction_to_prot(enum dma_data_direction dir, bool coherent)
>>>> +int dma_info_to_prot(enum dma_data_direction dir, bool coherent,
>>>> +		     unsigned long attrs)
>>>>  {
>>>>  	int prot = coherent ? IOMMU_CACHE : 0;
>>>>
>>>> +	if (attrs & DMA_ATTR_PRIVILEGED)
>>>> +		prot |= IOMMU_PRIV;
>>>> +
>>>>  	switch (dir) {
>>>>  	case DMA_BIDIRECTIONAL:
>>>>  		return prot | IOMMU_READ | IOMMU_WRITE;
>>>
>>> ...and applying against -next now also needs this hunk:
>>>
>>> @@ -639,7 +639,7 @@ dma_addr_t iommu_dma_map_resource(struct device
>>> *dev, phys_addr_t phys,
>>> 		size_t size, enum dma_data_direction dir, unsigned long attrs)
>>> {
>>> 	return __iommu_dma_map(dev, phys, size,
>>> -			dma_direction_to_prot(dir, false) | IOMMU_MMIO);
>>> +			dma_info_to_prot(dir, false, attrs) | IOMMU_MMIO);
>>> }
>>>
>>> void iommu_dma_unmap_resource(struct device *dev, dma_addr_t handle,
>>>
>>> With those two issues fixed up, I've given the series (applied to
>>> next-20161213) a spin on a SMMUv3/PL330 fast model and it still checks out.
>>>
>>
>> oops, sorry that i missed this in rebase. I can repost now with this fixed,
>> 'checks out' you mean something is not working correct ?
>
>No, I mean it _is_ still correct - I guess that's more of an idiom than
>I thought :)
>

ha ok, thanks for the testing as well. I will just send a v8 with those two fixed now.

Regards,
 Sricharan