---

yaml
---
r: 343572
b: refs/heads/master
c: 1cc8ed0
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 05dd85f7933ffbe6d71415e631c95ca615ae1e81
+refs/heads/master: 1cc8ed0b13ae6e076a1dd1f18da508b48c7aa05a

trunk/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();