1. Save the related domain pointer in struct iommu_dma_cookie, make iovad
   capable call domain->ops->flush_iotlb_all to flush TLB.
2. Add a new iommu capability: IOMMU_CAP_NON_STRICT, which used to indicate
   that the iommu domain support non-strict mode.
3. During the iommu domain initialization phase, call capable() to check
   whether it support non-strcit mode. If so, call init_iova_flush_queue
   to register iovad->flush_cb callback.
4. All unmap(contains iova-free) APIs will finally invoke __iommu_dma_unmap
   -->iommu_dma_free_iova. If the domain is non-strict, call queue_iova to
   put off iova freeing.

Signed-off-by: Zhen Lei <[email protected]>
---
 drivers/iommu/dma-iommu.c | 25 +++++++++++++++++++++++++
 include/linux/iommu.h     |  7 +++++++
 2 files changed, 32 insertions(+)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index ddcbbdb..9f0c77a 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -55,6 +55,7 @@ struct iommu_dma_cookie {
        };
        struct list_head                msi_page_list;
        spinlock_t                      msi_lock;
+       struct iommu_domain             *domain_non_strict;
 };
 
 static inline size_t cookie_msi_granule(struct iommu_dma_cookie *cookie)
@@ -257,6 +258,17 @@ static int iova_reserve_iommu_regions(struct device *dev,
        return ret;
 }
 
+static void iommu_dma_flush_iotlb_all(struct iova_domain *iovad)
+{
+       struct iommu_dma_cookie *cookie;
+       struct iommu_domain *domain;
+
+       cookie = container_of(iovad, struct iommu_dma_cookie, iovad);
+       domain = cookie->domain_non_strict;
+
+       domain->ops->flush_iotlb_all(domain);
+}
+
 /**
  * iommu_dma_init_domain - Initialise a DMA mapping domain
  * @domain: IOMMU domain previously prepared by iommu_get_dma_cookie()
@@ -272,6 +284,7 @@ static int iova_reserve_iommu_regions(struct device *dev,
 int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
                u64 size, struct device *dev)
 {
+       const struct iommu_ops *ops = domain->ops;
        struct iommu_dma_cookie *cookie = domain->iova_cookie;
        struct iova_domain *iovad = &cookie->iovad;
        unsigned long order, base_pfn, end_pfn;
@@ -308,6 +321,15 @@ int iommu_dma_init_domain(struct iommu_domain *domain, 
dma_addr_t base,
        }
 
        init_iova_domain(iovad, 1UL << order, base_pfn);
+
+       if ((ops->capable && ops->capable(IOMMU_CAP_NON_STRICT)) &&
+           (IOMMU_DOMAIN_STRICT_MODE(domain) == IOMMU_NON_STRICT)) {
+               BUG_ON(!ops->flush_iotlb_all);
+
+               cookie->domain_non_strict = domain;
+               init_iova_flush_queue(iovad, iommu_dma_flush_iotlb_all, NULL);
+       }
+
        if (!dev)
                return 0;
 
@@ -390,6 +412,9 @@ static void iommu_dma_free_iova(struct iommu_dma_cookie 
*cookie,
        /* The MSI case is only ever cleaning up its most recent allocation */
        if (cookie->type == IOMMU_DMA_MSI_COOKIE)
                cookie->msi_iova -= size;
+       else if (cookie->domain_non_strict)
+               queue_iova(iovad, iova_pfn(iovad, iova),
+                               size >> iova_shift(iovad), 0);
        else
                free_iova_fast(iovad, iova_pfn(iovad, iova),
                                size >> iova_shift(iovad));
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 19938ee..82ed979 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -86,6 +86,12 @@ struct iommu_domain_geometry {
 #define IOMMU_DOMAIN_DMA       (__IOMMU_DOMAIN_PAGING |        \
                                 __IOMMU_DOMAIN_DMA_API)
 
+#define IOMMU_STRICT           0
+#define IOMMU_NON_STRICT       1
+#define IOMMU_STRICT_MODE_MASK 1UL
+#define IOMMU_DOMAIN_STRICT_MODE(domain)       \
+               (domain->type != IOMMU_DOMAIN_UNMANAGED)
+
 struct iommu_domain {
        unsigned type;
        const struct iommu_ops *ops;
@@ -101,6 +107,7 @@ enum iommu_cap {
                                           transactions */
        IOMMU_CAP_INTR_REMAP,           /* IOMMU supports interrupt isolation */
        IOMMU_CAP_NOEXEC,               /* IOMMU_NOEXEC flag */
+       IOMMU_CAP_NON_STRICT,           /* IOMMU supports non-strict mode */
 };
 
 /*
-- 
1.8.3


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