[PATCH v5 2/5] iommu/dma: add support for non-strict mode

From: Zhen Lei
Date: Tue Aug 14 2018 - 21:32:40 EST


1. Save the related domain pointer in struct iommu_dma_cookie, make iovad
capable call domain->ops->flush_iotlb_all to flush TLB.
2. During the iommu domain initialization phase, base on domain->non_strict
field to check whether non-strict mode is supported or not. If so, call
init_iova_flush_queue to register iovad->flush_cb callback.
3. 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, and omit iommu_tlb_sync operation.

Signed-off-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx>
---
drivers/iommu/dma-iommu.c | 29 ++++++++++++++++++++++++++++-
drivers/iommu/iommu.c | 1 +
include/linux/iommu.h | 1 +
3 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index ddcbbdb..f0257e9 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -55,6 +55,9 @@ struct iommu_dma_cookie {
};
struct list_head msi_page_list;
spinlock_t msi_lock;
+
+ /* Only be assigned in non-strict mode, otherwise it's NULL */
+ struct iommu_domain *domain;
};

static inline size_t cookie_msi_granule(struct iommu_dma_cookie *cookie)
@@ -257,6 +260,17 @@ 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;
+
+ 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()
@@ -308,6 +322,14 @@ int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
}

init_iova_domain(iovad, 1UL << order, base_pfn);
+
+ if (domain->non_strict) {
+ BUG_ON(!domain->ops->flush_iotlb_all);
+
+ cookie->domain = 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 mode */
+ 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));
@@ -405,7 +430,9 @@ static void __iommu_dma_unmap(struct iommu_domain *domain, dma_addr_t dma_addr,
dma_addr -= iova_off;
size = iova_align(iovad, size + iova_off);

- WARN_ON(iommu_unmap(domain, dma_addr, size) != size);
+ WARN_ON(iommu_unmap_fast(domain, dma_addr, size) != size);
+ if (!domain->non_strict)
+ iommu_tlb_sync(domain);
iommu_dma_free_iova(cookie, dma_addr, size);
}

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 63b3756..6255a69 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1263,6 +1263,7 @@ static struct iommu_domain *__iommu_domain_alloc(struct bus_type *bus,

domain->ops = bus->iommu_ops;
domain->type = type;
+ domain->non_strict = false;
/* Assume all sizes by default; the driver may override this later */
domain->pgsize_bitmap = bus->iommu_ops->pgsize_bitmap;

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 19938ee..4bbcf39 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -88,6 +88,7 @@ struct iommu_domain_geometry {

struct iommu_domain {
unsigned type;
+ bool non_strict;
const struct iommu_ops *ops;
unsigned long pgsize_bitmap; /* Bitmap of page sizes in use */
iommu_fault_handler_t handler;
--
1.8.3