Messages in this thread | | | Subject | Re: [PATCH 5/7] iommu/dma: add support for non-strict mode | From | Robin Murphy <> | Date | Thu, 31 May 2018 14:04:47 +0100 |
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On 31/05/18 08:42, Zhen Lei wrote: > 1. Save the related domain pointer in struct iommu_dma_cookie, make iovad > capable call domain->ops->flush_iotlb_all to flush TLB. > 2. Define a new iommu capable: 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. Use iovad->flush_cb to check whether its related > iommu support non-strict mode or not, and call IOMMU_DOMAIN_IS_STRICT to > make sure the IOMMU_DOMAIN_UNMANAGED domain always follow strict mode.
Once again, this is a whole load of complexity for a property which could just be statically encoded at allocation, e.g. in the cookie type.
> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> > --- > drivers/iommu/dma-iommu.c | 29 ++++++++++++++++++++++++++--- > include/linux/iommu.h | 3 +++ > 2 files changed, 29 insertions(+), 3 deletions(-) > > diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c > index 4e885f7..2e116d9 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; > }; > > static inline size_t cookie_msi_granule(struct iommu_dma_cookie *cookie) > @@ -64,7 +65,8 @@ static inline size_t cookie_msi_granule(struct iommu_dma_cookie *cookie) > return PAGE_SIZE; > } > > -static struct iommu_dma_cookie *cookie_alloc(enum iommu_dma_cookie_type type) > +static struct iommu_dma_cookie *cookie_alloc(struct iommu_domain *domain, > + enum iommu_dma_cookie_type type) > { > struct iommu_dma_cookie *cookie; > > @@ -73,6 +75,7 @@ static struct iommu_dma_cookie *cookie_alloc(enum iommu_dma_cookie_type type) > spin_lock_init(&cookie->msi_lock); > INIT_LIST_HEAD(&cookie->msi_page_list); > cookie->type = type; > + cookie->domain = domain; > } > return cookie; > } > @@ -94,7 +97,7 @@ int iommu_get_dma_cookie(struct iommu_domain *domain) > if (domain->iova_cookie) > return -EEXIST; > > - domain->iova_cookie = cookie_alloc(IOMMU_DMA_IOVA_COOKIE); > + domain->iova_cookie = cookie_alloc(domain, IOMMU_DMA_IOVA_COOKIE); > if (!domain->iova_cookie) > return -ENOMEM; > > @@ -124,7 +127,7 @@ int iommu_get_msi_cookie(struct iommu_domain *domain, dma_addr_t base) > if (domain->iova_cookie) > return -EEXIST; > > - cookie = cookie_alloc(IOMMU_DMA_MSI_COOKIE); > + cookie = cookie_alloc(domain, IOMMU_DMA_MSI_COOKIE); > if (!cookie) > return -ENOMEM; > > @@ -261,6 +264,17 @@ static int iova_reserve_iommu_regions(struct device *dev, > return ret; > } > > +static void iova_flush_iotlb_all(struct iova_domain *iovad)
iommu_dma_flush...
> +{ > + 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() > @@ -276,6 +290,7 @@ 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; > @@ -313,6 +328,11 @@ 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)) { > + BUG_ON(!ops->flush_iotlb_all); > + init_iova_flush_queue(iovad, iova_flush_iotlb_all, NULL); > + } > + > return iova_reserve_iommu_regions(dev, domain); > } > EXPORT_SYMBOL(iommu_dma_init_domain); > @@ -392,6 +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 (!IOMMU_DOMAIN_IS_STRICT(cookie->domain) && iovad->flush_cb) > + 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 39b3150..01ff569 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -87,6 +87,8 @@ struct iommu_domain_geometry { > __IOMMU_DOMAIN_DMA_API) > > #define IOMMU_STRICT 1 > +#define IOMMU_DOMAIN_IS_STRICT(domain) \ > + (domain->type == IOMMU_DOMAIN_UNMANAGED) > > struct iommu_domain { > unsigned type; > @@ -103,6 +105,7 @@ 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 */
This isn't a property of the IOMMU, it depends purely on the driver implementation. I think it also doesn't matter anyway - if a caller asks for lazy unmapping on their domain but the IOMMU driver just does strict unmaps anyway because that's all it supports, there's no actual harm done.
Robin.
> }; > > /* >
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