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

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Date:   Wed, 6 Jun 2018 10:18:46 +0800
From:   Zhen Lei <thunder.leizhen@...wei.com>
To:     Joerg Roedel <joro@...tes.org>,
        iommu <iommu@...ts.linux-foundation.org>,
        linux-kernel <linux-kernel@...r.kernel.org>
CC:     Zhen Lei <thunder.leizhen@...wei.com>,
        Robin Murphy <robin.murphy@....com>
Subject: [PATCH 1/1] iommu/amd: make sure TLB to be flushed before IOVA freed

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