Re: [PATCH 4/7] iommu/amd: make sure TLB to be flushed before IOVA freed

["Leizhen (ThunderTown)" <thunder.leizhen@huawei.com>]

On 2018/5/31 21:04, Robin Murphy wrote:
> On 31/05/18 08:42, Zhen Lei wrote:
>> Although the mapping has already been removed in the page table, it maybe
>> still exist in TLB. Suppose the freed IOVAs is reused by others before the
>> flush operation completed, the new user can not correctly access to its
>> meomory.
> 
> This change seems reasonable in isolation, but why is it right in the middle of a series which has nothing to do with x86?
Because I described more in the previous patch, which may help this patch to be understood well.

You're right, I will repost this patch separately.

> 
> Robin.
> 
>> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
>> ---
>>   drivers/iommu/amd_iommu.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
>> index 8fb8c73..93aa389 100644
>> --- a/drivers/iommu/amd_iommu.c
>> +++ b/drivers/iommu/amd_iommu.c
>> @@ -2402,9 +2402,9 @@ static void __unmap_single(struct dma_ops_domain *dma_dom,
>>       }
>>         if (amd_iommu_unmap_flush) {
>> -        dma_ops_free_iova(dma_dom, dma_addr, pages);
>>           domain_flush_tlb(&dma_dom->domain);
>>           domain_flush_complete(&dma_dom->domain);
>> +        dma_ops_free_iova(dma_dom, dma_addr, pages);
>>       } else {
>>           pages = __roundup_pow_of_two(pages);
>>           queue_iova(&dma_dom->iovad, dma_addr >> PAGE_SHIFT, pages, 0);
>>
> 
> .
> 

-- 
Thanks!
BestRegards