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SubjectRe: [PATCH v10 05/12] iommu: Add IOMMU SVA domain support
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On 2022/7/5 13:07, Lu Baolu wrote:
> The sva iommu_domain represents a hardware pagetable that the IOMMU
> hardware could use for SVA translation. This adds some infrastructure
> to support SVA domain in the iommu common layer. It includes:
>
> - Extend the iommu_domain to support a new IOMMU_DOMAIN_SVA domain
> type. The IOMMU drivers that support allocation of the SVA domain
> should provide its own sva domain specific iommu_domain_ops.
> - Add a helper to allocate an SVA domain. The iommu_domain_free()
> is still used to free an SVA domain.
>
> The report_iommu_fault() should be replaced by the new
> iommu_report_device_fault(). Leave the existing fault handler with the
> existing users and the newly added SVA members excludes it.
>
> Suggested-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> Reviewed-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> Tested-by: Zhangfei Gao <zhangfei.gao@linaro.org>
> Tested-by: Tony Zhu <tony.zhu@intel.com>
> ---
> include/linux/iommu.h | 24 ++++++++++++++++++++++--
> drivers/iommu/iommu.c | 20 ++++++++++++++++++++
> 2 files changed, 42 insertions(+), 2 deletions(-)

Reviewed-by: Yi Liu <yi.l.liu@intel.com>

> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> index f2b5aa7efe43..42f0418dc22c 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -64,6 +64,8 @@ struct iommu_domain_geometry {
> #define __IOMMU_DOMAIN_PT (1U << 2) /* Domain is identity mapped */
> #define __IOMMU_DOMAIN_DMA_FQ (1U << 3) /* DMA-API uses flush queue */
>
> +#define __IOMMU_DOMAIN_SVA (1U << 4) /* Shared process address space */
> +
> /*
> * This are the possible domain-types
> *
> @@ -77,6 +79,8 @@ struct iommu_domain_geometry {
> * certain optimizations for these domains
> * IOMMU_DOMAIN_DMA_FQ - As above, but definitely using batched TLB
> * invalidation.
> + * IOMMU_DOMAIN_SVA - DMA addresses are shared process address
> + * spaces represented by mm_struct's.
> */
> #define IOMMU_DOMAIN_BLOCKED (0U)
> #define IOMMU_DOMAIN_IDENTITY (__IOMMU_DOMAIN_PT)
> @@ -86,15 +90,23 @@ struct iommu_domain_geometry {
> #define IOMMU_DOMAIN_DMA_FQ (__IOMMU_DOMAIN_PAGING | \
> __IOMMU_DOMAIN_DMA_API | \
> __IOMMU_DOMAIN_DMA_FQ)
> +#define IOMMU_DOMAIN_SVA (__IOMMU_DOMAIN_SVA)
>
> struct iommu_domain {
> unsigned type;
> const struct iommu_domain_ops *ops;
> unsigned long pgsize_bitmap; /* Bitmap of page sizes in use */
> - iommu_fault_handler_t handler;
> - void *handler_token;
> struct iommu_domain_geometry geometry;
> struct iommu_dma_cookie *iova_cookie;
> + union {
> + struct {
> + iommu_fault_handler_t handler;
> + void *handler_token;
> + };
> + struct { /* IOMMU_DOMAIN_SVA */
> + struct mm_struct *mm;
> + };
> + };
> };
>
> static inline bool iommu_is_dma_domain(struct iommu_domain *domain)
> @@ -685,6 +697,8 @@ int iommu_group_claim_dma_owner(struct iommu_group *group, void *owner);
> void iommu_group_release_dma_owner(struct iommu_group *group);
> bool iommu_group_dma_owner_claimed(struct iommu_group *group);
>
> +struct iommu_domain *iommu_sva_domain_alloc(struct device *dev,
> + struct mm_struct *mm);
> int iommu_attach_device_pasid(struct iommu_domain *domain, struct device *dev,
> ioasid_t pasid);
> void iommu_detach_device_pasid(struct iommu_domain *domain, struct device *dev,
> @@ -1063,6 +1077,12 @@ static inline bool iommu_group_dma_owner_claimed(struct iommu_group *group)
> return false;
> }
>
> +static inline struct iommu_domain *
> +iommu_sva_domain_alloc(struct device *dev, struct mm_struct *mm)
> +{
> + return NULL;
> +}
> +
> static inline int iommu_attach_device_pasid(struct iommu_domain *domain,
> struct device *dev, ioasid_t pasid)
> {
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index be48b09371f4..10479c5e4d23 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -27,6 +27,7 @@
> #include <linux/module.h>
> #include <linux/cc_platform.h>
> #include <trace/events/iommu.h>
> +#include <linux/sched/mm.h>
>
> static struct kset *iommu_group_kset;
> static DEFINE_IDA(iommu_group_ida);
> @@ -1957,6 +1958,8 @@ EXPORT_SYMBOL_GPL(iommu_domain_alloc);
>
> void iommu_domain_free(struct iommu_domain *domain)
> {
> + if (domain->type == IOMMU_DOMAIN_SVA)
> + mmdrop(domain->mm);
> iommu_put_dma_cookie(domain);
> domain->ops->free(domain);
> }
> @@ -3274,6 +3277,23 @@ bool iommu_group_dma_owner_claimed(struct iommu_group *group)
> }
> EXPORT_SYMBOL_GPL(iommu_group_dma_owner_claimed);
>
> +struct iommu_domain *iommu_sva_domain_alloc(struct device *dev,
> + struct mm_struct *mm)
> +{
> + const struct iommu_ops *ops = dev_iommu_ops(dev);
> + struct iommu_domain *domain;
> +
> + domain = ops->domain_alloc(IOMMU_DOMAIN_SVA);
> + if (!domain)
> + return NULL;
> +
> + domain->type = IOMMU_DOMAIN_SVA;
> + mmgrab(mm);
> + domain->mm = mm;
> +
> + return domain;
> +}
> +
> static bool iommu_group_immutable_singleton(struct iommu_group *group,
> struct device *dev)
> {

--
Regards,
Yi Liu

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