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iommu/amd: Allow downgrading page-sizes in alloc_pte() 

Before this patch it was not possible the downgrade a
mapping established with page-mode 7 to a mapping using
smaller page-sizes, because the pte_level != level check
prevented that.

Treat page-mode 7 like a non-present mapping and allow to
overwrite it in alloc_pte().

Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Joerg Roedel 2018-11-09 12:07:09 +01:00
parent 69be88520f
commit 6d568ef9a6
1 changed files with 9 additions and 3 deletions
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12
drivers/iommu/amd_iommu.c
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@ -1460,10 +1460,13 @@ static u64 *alloc_pte(struct protection_domain *domain,
while (level > end_lvl) {
u64 __pte, __npte;
int pte_level;
__pte = *pte;
__pte = *pte;
pte_level = PM_PTE_LEVEL(__pte);
if (!IOMMU_PTE_PRESENT(__pte)) {
if (!IOMMU_PTE_PRESENT(__pte) ||
pte_level == PAGE_MODE_7_LEVEL) {
page = (u64 *)get_zeroed_page(gfp);
if (!page)
return NULL;
@ -1475,10 +1478,13 @@ static u64 *alloc_pte(struct protection_domain *domain,
free_page((unsigned long)page);
continue;
}
if (pte_level == PAGE_MODE_7_LEVEL)
domain->updated = true;
}
/* No level skipping support yet */
if (PM_PTE_LEVEL(*pte) != level)
if (pte_level != level)
return NULL;
level -= 1;