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Commit 6f820bb9 authored by Joerg Roedel's avatar Joerg Roedel
Browse files

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: default avatarJoerg Roedel <jroedel@suse.de>
parent 9db034d5

drivers/iommu/amd_iommu.c

+27 −2
Original line number Diff line number Diff line
@@ -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;

}