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    SubjectRe: [PATCH v4 08/22] iommu: Introduce attach/detach_pasid_table API
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    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 */
    >
    >

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