e5992f2e6c
Add code that allows KVM to control the virtual memory layout that is seen by a guest. The guest address space uses a second page table that shares the last level pte-tables with the process page table. If a page is unmapped from the process page table it is automatically unmapped from the guest page table as well. The guest address space mapping starts out empty, KVM can map any individual 1MB segments from the process virtual memory to any 1MB aligned location in the guest virtual memory. If a target segment in the process virtual memory does not exist or is unmapped while a guest mapping exists the desired target address is stored as an invalid segment table entry in the guest page table. The population of the guest page table is fault driven. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
130 lines
2.5 KiB
C
130 lines
2.5 KiB
C
/*
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* IBM System z Huge TLB Page Support for Kernel.
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*
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* Copyright 2007 IBM Corp.
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* Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
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*/
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#include <linux/mm.h>
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#include <linux/hugetlb.h>
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void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
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pte_t *pteptr, pte_t pteval)
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{
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pmd_t *pmdp = (pmd_t *) pteptr;
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unsigned long mask;
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if (!MACHINE_HAS_HPAGE) {
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pteptr = (pte_t *) pte_page(pteval)[1].index;
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mask = pte_val(pteval) &
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(_SEGMENT_ENTRY_INV | _SEGMENT_ENTRY_RO);
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pte_val(pteval) = (_SEGMENT_ENTRY + __pa(pteptr)) | mask;
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}
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pmd_val(*pmdp) = pte_val(pteval);
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}
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int arch_prepare_hugepage(struct page *page)
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{
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unsigned long addr = page_to_phys(page);
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pte_t pte;
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pte_t *ptep;
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int i;
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if (MACHINE_HAS_HPAGE)
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return 0;
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ptep = (pte_t *) pte_alloc_one(&init_mm, addr);
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if (!ptep)
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return -ENOMEM;
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pte = mk_pte(page, PAGE_RW);
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for (i = 0; i < PTRS_PER_PTE; i++) {
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set_pte_at(&init_mm, addr + i * PAGE_SIZE, ptep + i, pte);
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pte_val(pte) += PAGE_SIZE;
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}
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page[1].index = (unsigned long) ptep;
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return 0;
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}
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void arch_release_hugepage(struct page *page)
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{
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pte_t *ptep;
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if (MACHINE_HAS_HPAGE)
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return;
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ptep = (pte_t *) page[1].index;
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if (!ptep)
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return;
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page_table_free(&init_mm, (unsigned long *) ptep);
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page[1].index = 0;
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}
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pte_t *huge_pte_alloc(struct mm_struct *mm,
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unsigned long addr, unsigned long sz)
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{
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pgd_t *pgdp;
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pud_t *pudp;
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pmd_t *pmdp = NULL;
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pgdp = pgd_offset(mm, addr);
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pudp = pud_alloc(mm, pgdp, addr);
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if (pudp)
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pmdp = pmd_alloc(mm, pudp, addr);
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return (pte_t *) pmdp;
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}
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pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
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{
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pgd_t *pgdp;
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pud_t *pudp;
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pmd_t *pmdp = NULL;
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pgdp = pgd_offset(mm, addr);
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if (pgd_present(*pgdp)) {
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pudp = pud_offset(pgdp, addr);
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if (pud_present(*pudp))
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pmdp = pmd_offset(pudp, addr);
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}
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return (pte_t *) pmdp;
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}
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int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
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{
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return 0;
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}
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struct page *follow_huge_addr(struct mm_struct *mm, unsigned long address,
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int write)
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{
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return ERR_PTR(-EINVAL);
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}
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int pmd_huge(pmd_t pmd)
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{
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if (!MACHINE_HAS_HPAGE)
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return 0;
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return !!(pmd_val(pmd) & _SEGMENT_ENTRY_LARGE);
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}
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int pud_huge(pud_t pud)
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{
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return 0;
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}
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struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address,
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pmd_t *pmdp, int write)
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{
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struct page *page;
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if (!MACHINE_HAS_HPAGE)
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return NULL;
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page = pmd_page(*pmdp);
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if (page)
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page += ((address & ~HPAGE_MASK) >> PAGE_SHIFT);
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return page;
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}
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