Re: [PATCH v4 08/22] iommu: Introduce attach/detach_pasid_table API

[Auger Eric <eric.auger@redhat.com>]

Hi,

On 6/18/19 5:41 PM, Jonathan Cameron wrote:
> On Sun, 9 Jun 2019 06:44:08 -0700
> Jacob Pan <jacob.jun.pan@linux.intel.com> wrote:
> 
>> In virtualization use case, when a guest is assigned
>> a PCI host device, protected by a virtual IOMMU on the guest,
>> the physical IOMMU must be programmed to be consistent with
>> the guest mappings. If the physical IOMMU supports two
>> translation stages it makes sense to program guest mappings
>> onto the first stage/level (ARM/Intel terminology) while the host
>> owns the stage/level 2.
>>
>> In that case, it is mandated to trap on guest configuration
>> settings and pass those to the physical iommu driver.
>>
>> This patch adds a new API to the iommu subsystem that allows
>> to set/unset the pasid table information.
>>
>> A generic iommu_pasid_table_config struct is introduced in
>> a new iommu.h uapi header. This is going to be used by the VFIO
>> user API.
> 
> Another case where strictly speaking stuff is introduced that this series
> doesn't use.  I don't know what the plans are to merge the various
> related series though so this might make sense in general. Right now
> it just bloats this series a bit..

I am now the only user of this API in
[PATCH v8 00/29] SMMUv3 Nested Stage Setup
(https://patchwork.kernel.org/cover/10961733/).

This can live in this series or Jean-Philippe do you intend to keep on
maintaining it in your api branch?

Thanks

Eric
>>
>> Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
>> Signed-off-by: Liu, Yi L <yi.l.liu@linux.intel.com>
>> Signed-off-by: Ashok Raj <ashok.raj@intel.com>
>> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
>> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>> Reviewed-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
>> ---
>>  drivers/iommu/iommu.c      | 19 +++++++++++++++++
>>  include/linux/iommu.h      | 18 ++++++++++++++++
>>  include/uapi/linux/iommu.h | 52 ++++++++++++++++++++++++++++++++++++++++++++++
>>  3 files changed, 89 insertions(+)
>>
>> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
>> index 166adb8..4496ccd 100644
>> --- a/drivers/iommu/iommu.c
>> +++ b/drivers/iommu/iommu.c
>> @@ -1619,6 +1619,25 @@ int iommu_page_response(struct device *dev,
>>  }
>>  EXPORT_SYMBOL_GPL(iommu_page_response);
>>  
>> +int iommu_attach_pasid_table(struct iommu_domain *domain,
>> +			     struct iommu_pasid_table_config *cfg)
>> +{
>> +	if (unlikely(!domain->ops->attach_pasid_table))
>> +		return -ENODEV;
>> +
>> +	return domain->ops->attach_pasid_table(domain, cfg);
>> +}
>> +EXPORT_SYMBOL_GPL(iommu_attach_pasid_table);
>> +
>> +void iommu_detach_pasid_table(struct iommu_domain *domain)
>> +{
>> +	if (unlikely(!domain->ops->detach_pasid_table))
>> +		return;
>> +
>> +	domain->ops->detach_pasid_table(domain);
>> +}
>> +EXPORT_SYMBOL_GPL(iommu_detach_pasid_table);
>> +
>>  static void __iommu_detach_device(struct iommu_domain *domain,
>>  				  struct device *dev)
>>  {
>> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
>> index 950347b..d3edb10 100644
>> --- a/include/linux/iommu.h
>> +++ b/include/linux/iommu.h
>> @@ -264,6 +264,8 @@ struct page_response_msg {
>>   * @sva_unbind: Unbind process address space from device
>>   * @sva_get_pasid: Get PASID associated to a SVA handle
>>   * @page_response: handle page request response
>> + * @attach_pasid_table: attach a pasid table
>> + * @detach_pasid_table: detach the pasid table
>>   * @pgsize_bitmap: bitmap of all possible supported page sizes
>>   */
>>  struct iommu_ops {
>> @@ -323,6 +325,9 @@ struct iommu_ops {
>>  				      void *drvdata);
>>  	void (*sva_unbind)(struct iommu_sva *handle);
>>  	int (*sva_get_pasid)(struct iommu_sva *handle);
>> +	int (*attach_pasid_table)(struct iommu_domain *domain,
>> +				  struct iommu_pasid_table_config *cfg);
>> +	void (*detach_pasid_table)(struct iommu_domain *domain);
>>  
>>  	int (*page_response)(struct device *dev, struct page_response_msg *msg);
>>  
>> @@ -434,6 +439,9 @@ extern int iommu_attach_device(struct iommu_domain *domain,
>>  			       struct device *dev);
>>  extern void iommu_detach_device(struct iommu_domain *domain,
>>  				struct device *dev);
>> +extern int iommu_attach_pasid_table(struct iommu_domain *domain,
>> +				    struct iommu_pasid_table_config *cfg);
>> +extern void iommu_detach_pasid_table(struct iommu_domain *domain);
>>  extern struct iommu_domain *iommu_get_domain_for_dev(struct device *dev);
>>  extern struct iommu_domain *iommu_get_dma_domain(struct device *dev);
>>  extern int iommu_map(struct iommu_domain *domain, unsigned long iova,
>> @@ -947,6 +955,13 @@ iommu_aux_get_pasid(struct iommu_domain *domain, struct device *dev)
>>  	return -ENODEV;
>>  }
>>  
>> +static inline
>> +int iommu_attach_pasid_table(struct iommu_domain *domain,
>> +			     struct iommu_pasid_table_config *cfg)
>> +{
>> +	return -ENODEV;
>> +}
>> +
>>  static inline struct iommu_sva *
>>  iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, void *drvdata)
>>  {
>> @@ -968,6 +983,9 @@ static inline int iommu_sva_get_pasid(struct iommu_sva *handle)
>>  	return IOMMU_PASID_INVALID;
>>  }
>>  
>> +static inline
>> +void iommu_detach_pasid_table(struct iommu_domain *domain) {}
>> +
>>  #endif /* CONFIG_IOMMU_API */
>>  
>>  #ifdef CONFIG_IOMMU_DEBUGFS
>> diff --git a/include/uapi/linux/iommu.h b/include/uapi/linux/iommu.h
>> index aaa3b6a..3976767 100644
>> --- a/include/uapi/linux/iommu.h
>> +++ b/include/uapi/linux/iommu.h
>> @@ -115,4 +115,56 @@ struct iommu_fault {
>>  		struct iommu_fault_page_request prm;
>>  	};
>>  };
>> +
>> +/**
>> + * struct iommu_pasid_smmuv3 - ARM SMMUv3 Stream Table Entry stage 1 related
>> + *     information
>> + * @version: API version of this structure
>> + * @s1fmt: STE s1fmt (format of the CD table: single CD, linear table
>> + *         or 2-level table)
>> + * @s1dss: STE s1dss (specifies the behavior when @pasid_bits != 0
>> + *         and no PASID is passed along with the incoming transaction)
>> + * @padding: reserved for future use (should be zero)
>> + *
>> + * The PASID table is referred to as the Context Descriptor (CD) table on ARM
>> + * SMMUv3. Please refer to the ARM SMMU 3.x spec (ARM IHI 0070A) for full
>> + * details.
>> + */
>> +struct iommu_pasid_smmuv3 {
>> +#define PASID_TABLE_SMMUV3_CFG_VERSION_1 1
>> +	__u32	version;
>> +	__u8	s1fmt;
>> +	__u8	s1dss;
>> +	__u8	padding[2];
>> +};
>> +
>> +/**
>> + * struct iommu_pasid_table_config - PASID table data used to bind guest PASID
>> + *     table to the host IOMMU
>> + * @version: API version to prepare for future extensions
>> + * @format: format of the PASID table
>> + * @base_ptr: guest physical address of the PASID table
>> + * @pasid_bits: number of PASID bits used in the PASID table
>> + * @config: indicates whether the guest translation stage must
>> + *          be translated, bypassed or aborted.
>> + * @padding: reserved for future use (should be zero)
>> + * @smmuv3: table information when @format is %IOMMU_PASID_FORMAT_SMMUV3
>> + */
>> +struct iommu_pasid_table_config {
>> +#define PASID_TABLE_CFG_VERSION_1 1
>> +	__u32	version;
>> +#define IOMMU_PASID_FORMAT_SMMUV3	1
>> +	__u32	format;
>> +	__u64	base_ptr;
>> +	__u8	pasid_bits;
>> +#define IOMMU_PASID_CONFIG_TRANSLATE	1
>> +#define IOMMU_PASID_CONFIG_BYPASS	2
>> +#define IOMMU_PASID_CONFIG_ABORT	3
>> +	__u8	config;
>> +	__u8    padding[6];
>> +	union {
>> +		struct iommu_pasid_smmuv3 smmuv3;
>> +	};
>> +};
>> +
>>  #endif /* _UAPI_IOMMU_H */
> 
>