x86/amd-iommu: Fix rounding-bug in __unmap_single

commit 04e0463e088b41060c08c255eb0d3278a504f094 upstream.

In the __unmap_single function the dma_addr is rounded down
to a page boundary before the dma pages are unmapped. The
address is later also used to flush the TLB entries for that
mapping. But without the offset into the dma page the amount
of pages to flush might be miscalculated in the TLB flushing
path. This patch fixes this bug by using the original
address to flush the TLB.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 29e5e6ea0bfb70b5a886c44771ee58ff68ace0ba..1aae6178eb016ece46e4c59616665d60e9f8f205 100644 (file)
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -1886,6 +1886,7 @@ static void __unmap_single(struct dma_ops_domain *dma_dom,
                           size_t size,
                           int dir)
 {
+       dma_addr_t flush_addr;
        dma_addr_t i, start;
        unsigned int pages;
 
@@ -1893,6 +1894,7 @@ static void __unmap_single(struct dma_ops_domain *dma_dom,
            (dma_addr + size > dma_dom->aperture_size))
                return;
 
+       flush_addr = dma_addr;
        pages = iommu_num_pages(dma_addr, size, PAGE_SIZE);
        dma_addr &= PAGE_MASK;
        start = dma_addr;
@@ -1907,7 +1909,7 @@ static void __unmap_single(struct dma_ops_domain *dma_dom,
        dma_ops_free_addresses(dma_dom, dma_addr, pages);
 
        if (amd_iommu_unmap_flush || dma_dom->need_flush) {
-               iommu_flush_pages(&dma_dom->domain, dma_addr, size);
+               iommu_flush_pages(&dma_dom->domain, flush_addr, size);
                dma_dom->need_flush = false;
        }
 }