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

Jonathan Cameron
2019-06-18T15:41:49Z

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..
>
> 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 */