diff options
Diffstat (limited to 'arch/powerpc/kvm/book3s_64_mmu_hv.c')
| -rw-r--r-- | arch/powerpc/kvm/book3s_64_mmu_hv.c | 39 |
1 files changed, 36 insertions, 3 deletions
diff --git a/arch/powerpc/kvm/book3s_64_mmu_hv.c b/arch/powerpc/kvm/book3s_64_mmu_hv.c index 83761dd8a92..66d6452c108 100644 --- a/arch/powerpc/kvm/book3s_64_mmu_hv.c +++ b/arch/powerpc/kvm/book3s_64_mmu_hv.c @@ -503,6 +503,7 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu, struct page *page, *pages[1]; long index, ret, npages; unsigned long is_io; + unsigned int writing, write_ok; struct vm_area_struct *vma; /* @@ -553,8 +554,11 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu, pfn = 0; page = NULL; 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, 1, pages); + npages = get_user_pages_fast(hva, 1, writing, pages); if (npages < 1) { /* Check if it's an I/O mapping */ down_read(¤t->mm->mmap_sem); @@ -565,6 +569,7 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu, ((hva - vma->vm_start) >> PAGE_SHIFT); pte_size = psize; is_io = hpte_cache_bits(pgprot_val(vma->vm_page_prot)); + write_ok = vma->vm_flags & VM_WRITE; } up_read(¤t->mm->mmap_sem); if (!pfn) @@ -575,6 +580,24 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu, 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; + + /* + * We need to protect against page table destruction + * while looking up and updating the pte. + */ + rcu_read_lock_sched(); + ptep = find_linux_pte_or_hugepte(current->mm->pgd, + hva, NULL); + if (ptep && pte_present(*ptep)) { + pte = kvmppc_read_update_linux_pte(ptep, 1); + if (pte_write(pte)) + write_ok = 1; + } + rcu_read_unlock_sched(); + } pfn = page_to_pfn(page); } @@ -595,6 +618,8 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu, /* Set the HPTE to point to pfn */ r = (r & ~(HPTE_R_PP0 - pte_size)) | (pfn << PAGE_SHIFT); + if (hpte_is_writable(r) && !write_ok) + r = hpte_make_readonly(r); ret = RESUME_GUEST; preempt_disable(); while (!try_lock_hpte(hptep, HPTE_V_HVLOCK)) @@ -614,14 +639,22 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu, unlock_rmap(rmap); goto out_unlock; } - kvmppc_add_revmap_chain(kvm, rev, rmap, index, 0); + + if (hptep[0] & HPTE_V_VALID) { + /* HPTE was previously valid, so we need to invalidate it */ + unlock_rmap(rmap); + hptep[0] |= HPTE_V_ABSENT; + kvmppc_invalidate_hpte(kvm, hptep, index); + } else { + kvmppc_add_revmap_chain(kvm, rev, rmap, index, 0); + } hptep[1] = r; eieio(); hptep[0] = hpte[0]; asm volatile("ptesync" : : : "memory"); preempt_enable(); - if (page) + if (page && hpte_is_writable(r)) SetPageDirty(page); out_put: |