iommu: Add IOMMU SVA domain support

The SVA iommu_domain represents a hardware pagetable that the IOMMU
hardware could use for SVA translation. This adds some infrastructures
to support SVA domain in the iommu core. 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>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Yi Liu <yi.l.liu@intel.com>
Tested-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Tested-by: Tony Zhu <tony.zhu@intel.com>
Link: https://lore.kernel.org/r/20221031005917.45690-7-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index bf22992..6a1cd20 100644 (file)
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -29,6 +29,7 @@
 #include <linux/module.h>
 #include <linux/cc_platform.h>
 #include <trace/events/iommu.h>
+#include <linux/sched/mm.h>
 
 #include "dma-iommu.h"
 
@@ -1934,6 +1935,8 @@ 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);
 }
@@ -3383,3 +3386,20 @@ struct iommu_domain *iommu_get_domain_for_dev_pasid(struct device *dev,
        return domain;
 }
 EXPORT_SYMBOL_GPL(iommu_get_domain_for_dev_pasid);
+
+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;
+}

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 5d2b78a..776baa3 100644 (file)
--- 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 addresses
+ *                               represented by mm_struct's.
  */
 #define IOMMU_DOMAIN_BLOCKED   (0U)
 #define IOMMU_DOMAIN_IDENTITY  (__IOMMU_DOMAIN_PT)
@@ -86,15 +90,24 @@ 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;
+                       int users;
+               };
+       };
 };
 
 static inline bool iommu_is_dma_domain(struct iommu_domain *domain)
@@ -685,6 +698,8 @@ 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,
@@ -1055,6 +1070,12 @@ 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)
 {