From: Joerg Roedel <jroedel@xxxxxxx>
Before this patch the iommu_map_page() function failed when
it tried to map a huge-page where smaller mappings existed
before.
With this change the page-table pages of the old mappings
are teared down, so that the huge-page can be mapped.
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
---
drivers/iommu/amd_iommu.c | 29 +++++++++++++++++++++++++++--
1 file changed, 27 insertions(+), 2 deletions(-)
diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index c539b2a59019..71797b3d67e5 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -1557,6 +1557,25 @@ static u64 *fetch_pte(struct protection_domain *domain,
return pte;
}
+static struct page *free_clear_pte(u64 *pte, u64 pteval, struct page *freelist)
+{
+ unsigned long pt;
+ int mode;
+
+ while (cmpxchg64(pte, pteval, 0) != pteval) {
+ pr_warn("AMD-Vi: IOMMU pte changed since we read it\n");
+ pteval = *pte;
+ }
+
+ if (!IOMMU_PTE_PRESENT(pteval))
+ return freelist;
+
+ pt = (unsigned long)IOMMU_PTE_PAGE(pteval);
+ mode = IOMMU_PTE_MODE(pteval);
+
+ return free_sub_pt(pt, mode, freelist);
+}
+
/*
* Generic mapping functions. It maps a physical address into a DMA
* address space. It allocates the page table pages if necessary.
@@ -1571,6 +1590,7 @@ static int iommu_map_page(struct protection_domain *dom,
int prot,
gfp_t gfp)
{
+ struct page *freelist = NULL;
u64 __pte, *pte;
int i, count;
@@ -1587,8 +1607,10 @@ static int iommu_map_page(struct protection_domain *dom,
return -ENOMEM;
for (i = 0; i < count; ++i)
- if (IOMMU_PTE_PRESENT(pte[i]))
- return -EBUSY;
+ freelist = free_clear_pte(&pte[i], pte[i], freelist);
+
+ if (freelist != NULL)
+ dom->updated = true;
if (count > 1) {
__pte = PAGE_SIZE_PTE(__sme_set(phys_addr), page_size);
@@ -1606,6 +1628,9 @@ static int iommu_map_page(struct protection_domain *dom,
update_domain(dom);
+ /* Everything flushed out, free pages now */
+ free_page_list(freelist);
+
return 0;
}
--
2.17.1
