diff options
| -rw-r--r-- | arch/powerpc/kvm/book3s_hv_rm_mmu.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c b/arch/powerpc/kvm/book3s_hv_rm_mmu.c index fc3da3208fda..7a57ea49172d 100644 --- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c +++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c @@ -600,6 +600,28 @@ long kvmppc_h_protect(struct kvm_vcpu *vcpu, unsigned long flags, asm volatile("tlbiel %0" : : "r" (rb)); asm volatile("ptesync" : : : "memory"); } + /* + * If the host has this page as readonly but the guest + * wants to make it read/write, reduce the permissions. + * Checking the host permissions involves finding the + * memslot and then the Linux PTE for the page. + */ + if (hpte_is_writable(r) && kvm->arch.using_mmu_notifiers) { + unsigned long psize, gfn, hva; + struct kvm_memory_slot *memslot; + pgd_t *pgdir = vcpu->arch.pgdir; + pte_t pte; + + psize = hpte_page_size(v, r); + gfn = ((r & HPTE_R_RPN) & ~(psize - 1)) >> PAGE_SHIFT; + memslot = __gfn_to_memslot(kvm_memslots(kvm), gfn); + if (memslot) { + hva = __gfn_to_hva_memslot(memslot, gfn); + pte = lookup_linux_pte(pgdir, hva, 1, &psize); + if (pte_present(pte) && !pte_write(pte)) + r = hpte_make_readonly(r); + } + } } hpte[1] = r; eieio(); |