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Subject[PATCH v6 2/7] iommu/dma: Add support for non-strict mode
Date
From: Zhen Lei <thunder.leizhen@huawei.com>

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@huawei.com>
[rm: convert raw boolean to domain attribute]
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---
drivers/iommu/dma-iommu.c | 31 ++++++++++++++++++++++++++++++-
include/linux/iommu.h | 1 +
2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 511ff9a1d6d9..d91849fe4ebe 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -55,8 +55,13 @@ 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 bool iommu_dma_non_strict __read_mostly;
+
static inline size_t cookie_msi_granule(struct iommu_dma_cookie *cookie)
{
if (cookie->type == IOMMU_DMA_IOVA_COOKIE)
@@ -257,6 +262,17 @@ 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()
@@ -275,6 +291,7 @@ int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
struct iommu_dma_cookie *cookie = domain->iova_cookie;
struct iova_domain *iovad = &cookie->iovad;
unsigned long order, base_pfn, end_pfn;
+ int attr = 1;

if (!cookie || cookie->type != IOMMU_DMA_IOVA_COOKIE)
return -EINVAL;
@@ -308,6 +325,13 @@ int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
}

init_iova_domain(iovad, 1UL << order, base_pfn);
+
+ if (iommu_dma_non_strict && !iommu_domain_set_attr(domain,
+ DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE, &attr)) {
+ cookie->domain = domain;
+ init_iova_flush_queue(iovad, iommu_dma_flush_iotlb_all, NULL);
+ }
+
if (!dev)
return 0;

@@ -393,6 +417,9 @@ 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));
@@ -408,7 +435,9 @@ 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 (!cookie->domain)
+ iommu_tlb_sync(domain);
iommu_dma_free_iova(cookie, dma_addr, size);
}

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 87994c265bf5..decabe8e8dbe 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -124,6 +124,7 @@ enum iommu_attr {
DOMAIN_ATTR_FSL_PAMU_ENABLE,
DOMAIN_ATTR_FSL_PAMUV1,
DOMAIN_ATTR_NESTING, /* two stages of translation */
+ DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE,
DOMAIN_ATTR_MAX,
};

--
2.19.0.dirty
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