diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/powerpc/kvm/book3s_64_mmu_hv.c | 119 |
1 files changed, 57 insertions, 62 deletions
diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c index 6c372f5c61b6..3aecec890d6f 100644 --- a/arch/powerpc/kvm/book3s_64_mmu_hv.c +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c @@ -485,18 +485,18 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu, __be64 *hptep; unsigned long mmu_seq, psize, pte_size; unsigned long gpa_base, gfn_base; - unsigned long gpa, gfn, hva, pfn; + unsigned long gpa, gfn, hva, pfn, hpa; struct kvm_memory_slot *memslot; unsigned long *rmap; struct revmap_entry *rev; - struct page *page, *pages[1]; - long index, ret, npages; + struct page *page; + long index, ret; bool is_ci; - unsigned int writing, write_ok; - struct vm_area_struct *vma; + bool writing, write_ok; + unsigned int shift; unsigned long rcbits; long mmio_update; - struct mm_struct *mm; + pte_t pte, *ptep; if (kvm_is_radix(kvm)) return kvmppc_book3s_radix_page_fault(run, vcpu, ea, dsisr); @@ -570,59 +570,62 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu, smp_rmb(); ret = -EFAULT; - is_ci = false; - pfn = 0; page = NULL; - mm = kvm->mm; - pte_size = PAGE_SIZE; writing = (dsisr & DSISR_ISSTORE) != 0; /* If writing != 0, then the HPTE must allow writing, if we get here */ write_ok = writing; hva = gfn_to_hva_memslot(memslot, gfn); - npages = get_user_pages_fast(hva, 1, writing ? FOLL_WRITE : 0, pages); - if (npages < 1) { - /* Check if it's an I/O mapping */ - down_read(&mm->mmap_sem); - vma = find_vma(mm, hva); - if (vma && vma->vm_start <= hva && hva + psize <= vma->vm_end && - (vma->vm_flags & VM_PFNMAP)) { - pfn = vma->vm_pgoff + - ((hva - vma->vm_start) >> PAGE_SHIFT); - pte_size = psize; - is_ci = pte_ci(__pte((pgprot_val(vma->vm_page_prot)))); - write_ok = vma->vm_flags & VM_WRITE; - } - up_read(&mm->mmap_sem); - if (!pfn) - goto out_put; + + /* + * Do a fast check first, since __gfn_to_pfn_memslot doesn't + * do it with !atomic && !async, which is how we call it. + * We always ask for write permission since the common case + * is that the page is writable. + */ + if (__get_user_pages_fast(hva, 1, 1, &page) == 1) { + write_ok = true; } else { - page = pages[0]; - pfn = page_to_pfn(page); - if (PageHuge(page)) { - page = compound_head(page); - pte_size <<= compound_order(page); - } - /* if the guest wants write access, see if that is OK */ - if (!writing && hpte_is_writable(r)) { - pte_t *ptep, pte; - unsigned long flags; - /* - * We need to protect against page table destruction - * hugepage split and collapse. - */ - local_irq_save(flags); - ptep = find_current_mm_pte(mm->pgd, hva, NULL, NULL); - if (ptep) { - pte = kvmppc_read_update_linux_pte(ptep, 1); - if (__pte_write(pte)) - write_ok = 1; - } - local_irq_restore(flags); + /* Call KVM generic code to do the slow-path check */ + pfn = __gfn_to_pfn_memslot(memslot, gfn, false, NULL, + writing, &write_ok); + if (is_error_noslot_pfn(pfn)) + return -EFAULT; + page = NULL; + if (pfn_valid(pfn)) { + page = pfn_to_page(pfn); + if (PageReserved(page)) + page = NULL; } } + /* + * Read the PTE from the process' radix tree and use that + * so we get the shift and attribute bits. + */ + local_irq_disable(); + ptep = __find_linux_pte(vcpu->arch.pgdir, hva, NULL, &shift); + /* + * If the PTE disappeared temporarily due to a THP + * collapse, just return and let the guest try again. + */ + if (!ptep) { + local_irq_enable(); + if (page) + put_page(page); + return RESUME_GUEST; + } + pte = *ptep; + local_irq_enable(); + hpa = pte_pfn(pte) << PAGE_SHIFT; + pte_size = PAGE_SIZE; + if (shift) + pte_size = 1ul << shift; + is_ci = pte_ci(pte); + if (psize > pte_size) goto out_put; + if (pte_size > psize) + hpa |= hva & (pte_size - psize); /* Check WIMG vs. the actual page we're accessing */ if (!hpte_cache_flags_ok(r, is_ci)) { @@ -636,14 +639,13 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu, } /* - * Set the HPTE to point to pfn. - * Since the pfn is at PAGE_SIZE granularity, make sure we + * Set the HPTE to point to hpa. + * Since the hpa is at PAGE_SIZE granularity, make sure we * don't mask out lower-order bits if psize < PAGE_SIZE. */ if (psize < PAGE_SIZE) psize = PAGE_SIZE; - r = (r & HPTE_R_KEY_HI) | (r & ~(HPTE_R_PP0 - psize)) | - ((pfn << PAGE_SHIFT) & ~(psize - 1)); + r = (r & HPTE_R_KEY_HI) | (r & ~(HPTE_R_PP0 - psize)) | hpa; if (hpte_is_writable(r) && !write_ok) r = hpte_make_readonly(r); ret = RESUME_GUEST; @@ -708,20 +710,13 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu, asm volatile("ptesync" : : : "memory"); preempt_enable(); if (page && hpte_is_writable(r)) - SetPageDirty(page); + set_page_dirty_lock(page); out_put: trace_kvm_page_fault_exit(vcpu, hpte, ret); - if (page) { - /* - * We drop pages[0] here, not page because page might - * have been set to the head page of a compound, but - * we have to drop the reference on the correct tail - * page to match the get inside gup() - */ - put_page(pages[0]); - } + if (page) + put_page(page); return ret; out_unlock: |