linux-kernel - Re: [PATCH 1/1] iommu/amd: make sure TLB to be flushed before IOVA freed

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Message-ID: <5B2B40F6.50309@huawei.com>
Date:   Thu, 21 Jun 2018 14:08:54 +0800
From:   "Leizhen (ThunderTown)" <thunder.leizhen@...wei.com>
To:     Joerg Roedel <joro@...tes.org>,
        iommu <iommu@...ts.linux-foundation.org>,
        linux-kernel <linux-kernel@...r.kernel.org>
CC:     Robin Murphy <robin.murphy@....com>
Subject: Re: [PATCH 1/1] iommu/amd: make sure TLB to be flushed before IOVA
 freed

Hi Joerg:
  Can you take a look at it?


On 2018/6/6 10:18, 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.
> 
> Signed-off-by: Zhen Lei <thunder.leizhen@...wei.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);
> --
> 1.8.3
> 
> 
> 
> .
> 

-- 
Thanks!
BestRegards