Re: [PATCH v4 2/5] iommu/dma: add support for non-strict mode

From: Leizhen (ThunderTown)
Date: Thu Aug 09 2018 - 07:01:23 EST




On 2018/8/9 18:46, Robin Murphy wrote:
> On 06/08/18 13:27, 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. 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.
>>
>> Signed-off-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx>
>> ---
>> drivers/iommu/dma-iommu.c | 23 +++++++++++++++++++++++
>> drivers/iommu/iommu.c | 1 +
>> include/linux/iommu.h | 1 +
>> 3 files changed, 25 insertions(+)
>>
>> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
>> index ddcbbdb..213e62a 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)
>> @@ -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;
>> +
>> + 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 +320,14 @@ 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;
>
> cookie->domain will only be non-NULL if domain->non_strict is true...
>
>> + init_iova_flush_queue(iovad, iommu_dma_flush_iotlb_all, NULL);
>> + }
>> +
>> if (!dev)
>> return 0;
>>
>> @@ -390,6 +410,9 @@ 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 && cookie->domain->non_strict)
>
> ...so we don't need to re-check non_strict every time here.

OK, I will change it to a comment.

>
>> + 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/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
>> index 63b3756..7811fde 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 = 0;
>> /* 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..0a0fb48 100644
>> --- a/include/linux/iommu.h
>> +++ b/include/linux/iommu.h
>> @@ -88,6 +88,7 @@ struct iommu_domain_geometry {
>>
>> struct iommu_domain {
>> unsigned type;
>> + int non_strict;
>
> bool?

OK

>
> Robin.
>
>> const struct iommu_ops *ops;
>> unsigned long pgsize_bitmap; /* Bitmap of page sizes in use */
>> iommu_fault_handler_t handler;
>> --
>> 1.8.3
>>
>>
>
> .
>

--
Thanks!
BestRegards