RE: [RFC 09/20] iommu: Add page size and address width attributes

2021-09-22 Thread Tian, Kevin 
> From: Eric Auger 
> Sent: Wednesday, September 22, 2021 9:43 PM
> 
> Hi,
> 
> On 9/19/21 8:38 AM, Liu Yi L wrote:
> > From: Lu Baolu 
> >
> > This exposes PAGE_SIZE and ADDR_WIDTH attributes. The iommufd could
> use
> > them to define the IOAS.
> >
> > Signed-off-by: Lu Baolu 
> > ---
> >  include/linux/iommu.h | 4 
> >  1 file changed, 4 insertions(+)
> >
> > diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> > index 943de6897f56..86d34e4ce05e 100644
> > --- a/include/linux/iommu.h
> > +++ b/include/linux/iommu.h
> > @@ -153,9 +153,13 @@ enum iommu_dev_features {
> >  /**
> >   * enum iommu_devattr - Per device IOMMU attributes
> >   * @IOMMU_DEV_INFO_FORCE_SNOOP [bool]: IOMMU can force DMA to
> be snooped.
> > + * @IOMMU_DEV_INFO_PAGE_SIZE [u64]: Page sizes that iommu
> supports.
> > + * @IOMMU_DEV_INFO_ADDR_WIDTH [u32]: Address width supported.
> I think this deserves additional info. What address width do we talk
> about, input, output, what stage if the IOMMU does support multiple stages
> 

it describes the address space width, thus is about input.

when multiple stages are supported, each stage is represented by a separate
ioasid, each with its own addr_width
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Re: [RFC 09/20] iommu: Add page size and address width attributes

2021-09-22 Thread Eric Auger 
Hi,

On 9/19/21 8:38 AM, Liu Yi L wrote:
> From: Lu Baolu 
>
> This exposes PAGE_SIZE and ADDR_WIDTH attributes. The iommufd could use
> them to define the IOAS.
>
> Signed-off-by: Lu Baolu 
> ---
>  include/linux/iommu.h | 4 
>  1 file changed, 4 insertions(+)
>
> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> index 943de6897f56..86d34e4ce05e 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -153,9 +153,13 @@ enum iommu_dev_features {
>  /**
>   * enum iommu_devattr - Per device IOMMU attributes
>   * @IOMMU_DEV_INFO_FORCE_SNOOP [bool]: IOMMU can force DMA to be snooped.
> + * @IOMMU_DEV_INFO_PAGE_SIZE [u64]: Page sizes that iommu supports.
> + * @IOMMU_DEV_INFO_ADDR_WIDTH [u32]: Address width supported.
I think this deserves additional info. What address width do we talk
about, input, output, what stage if the IOMMU does support multiple stages

Thanks

Eric
>   */
>  enum iommu_devattr {
>   IOMMU_DEV_INFO_FORCE_SNOOP,
> + IOMMU_DEV_INFO_PAGE_SIZE,
> + IOMMU_DEV_INFO_ADDR_WIDTH,
>  };
>  
>  #define IOMMU_PASID_INVALID  (-1U)

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[RFC 09/20] iommu: Add page size and address width attributes

2021-09-19 Thread Liu Yi L 
From: Lu Baolu 

This exposes PAGE_SIZE and ADDR_WIDTH attributes. The iommufd could use
them to define the IOAS.

Signed-off-by: Lu Baolu 
---
 include/linux/iommu.h | 4 
 1 file changed, 4 insertions(+)

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 943de6897f56..86d34e4ce05e 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -153,9 +153,13 @@ enum iommu_dev_features {
 /**
  * enum iommu_devattr - Per device IOMMU attributes
  * @IOMMU_DEV_INFO_FORCE_SNOOP [bool]: IOMMU can force DMA to be snooped.
+ * @IOMMU_DEV_INFO_PAGE_SIZE [u64]: Page sizes that iommu supports.
+ * @IOMMU_DEV_INFO_ADDR_WIDTH [u32]: Address width supported.
  */
 enum iommu_devattr {
IOMMU_DEV_INFO_FORCE_SNOOP,
+   IOMMU_DEV_INFO_PAGE_SIZE,
+   IOMMU_DEV_INFO_ADDR_WIDTH,
 };
 
 #define IOMMU_PASID_INVALID(-1U)
-- 
2.25.1

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