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iommu/amd: Allow to upgrade page-size 

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@suse.de>
This commit is contained in:
Joerg Roedel 2018-11-09 12:07:11 +01:00
parent 9db034d57a
commit 6f820bb995
1 changed files with 27 additions and 2 deletions
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29
drivers/iommu/amd_iommu.c
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@ -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;
}