-/*
- * This is called to get a reference to a guest page if there isn't
- * one already in the memslot->arch.slot_phys[] array.
- */
-static long kvmppc_get_guest_page(struct kvm *kvm, unsigned long gfn,
- struct kvm_memory_slot *memslot,
- unsigned long psize)
-{
- unsigned long start;
- long np, err;
- struct page *page, *hpage, *pages[1];
- unsigned long s, pgsize;
- unsigned long *physp;
- unsigned int is_io, got, pgorder;
- struct vm_area_struct *vma;
- unsigned long pfn, i, npages;
-
- physp = memslot->arch.slot_phys;
- if (!physp)
- return -EINVAL;
- if (physp[gfn - memslot->base_gfn])
- return 0;
-
- is_io = 0;
- got = 0;
- page = NULL;
- pgsize = psize;
- err = -EINVAL;
- start = gfn_to_hva_memslot(memslot, gfn);
-
- /* Instantiate and get the page we want access to */
- np = get_user_pages_fast(start, 1, 1, pages);
- if (np != 1) {
- /* Look up the vma for the page */
- down_read(¤t->mm->mmap_sem);
- vma = find_vma(current->mm, start);
- if (!vma || vma->vm_start > start ||
- start + psize > vma->vm_end ||
- !(vma->vm_flags & VM_PFNMAP))
- goto up_err;
- is_io = hpte_cache_bits(pgprot_val(vma->vm_page_prot));
- pfn = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
- /* check alignment of pfn vs. requested page size */
- if (psize > PAGE_SIZE && (pfn & ((psize >> PAGE_SHIFT) - 1)))
- goto up_err;
- up_read(¤t->mm->mmap_sem);
-
- } else {
- page = pages[0];
- got = KVMPPC_GOT_PAGE;
-
- /* See if this is a large page */
- s = PAGE_SIZE;
- if (PageHuge(page)) {
- hpage = compound_head(page);
- s <<= compound_order(hpage);
- /* Get the whole large page if slot alignment is ok */
- if (s > psize && slot_is_aligned(memslot, s) &&
- !(memslot->userspace_addr & (s - 1))) {
- start &= ~(s - 1);
- pgsize = s;
- get_page(hpage);
- put_page(page);
- page = hpage;
- }
- }
- if (s < psize)
- goto out;
- pfn = page_to_pfn(page);
- }
-
- npages = pgsize >> PAGE_SHIFT;
- pgorder = __ilog2(npages);
- physp += (gfn - memslot->base_gfn) & ~(npages - 1);
- spin_lock(&kvm->arch.slot_phys_lock);
- for (i = 0; i < npages; ++i) {
- if (!physp[i]) {
- physp[i] = ((pfn + i) << PAGE_SHIFT) +
- got + is_io + pgorder;
- got = 0;
- }
- }
- spin_unlock(&kvm->arch.slot_phys_lock);
- err = 0;
-
- out:
- if (got)
- put_page(page);
- return err;
-
- up_err:
- up_read(¤t->mm->mmap_sem);
- return err;
-}
-