add REDIRECT

hc

2024-10-09 05e59e5fb0064c97a1c10921ecd549f2d4a58565

 kernel/arch/arm64/include/asm/kvm_emulate.h
..
..
@@ -363,8 +363,26 @@
363
363
 
364
364
 static inline bool kvm_is_write_fault(struct kvm_vcpu *vcpu)
365
365
 {
366
-	if (kvm_vcpu_abt_iss1tw(vcpu))
367
-		return true;
366
+	if (kvm_vcpu_abt_iss1tw(vcpu)) {
367
+		/*
368
+		 * Only a permission fault on a S1PTW should be
369
+		 * considered as a write. Otherwise, page tables baked
370
+		 * in a read-only memslot will result in an exception
371
+		 * being delivered in the guest.
372
+		 *
373
+		 * The drawback is that we end-up faulting twice if the
374
+		 * guest is using any of HW AF/DB: a translation fault
375
+		 * to map the page containing the PT (read only at
376
+		 * first), then a permission fault to allow the flags
377
+		 * to be set.
378
+		 */
379
+		switch (kvm_vcpu_trap_get_fault_type(vcpu)) {
380
+		case ESR_ELx_FSC_PERM:
381
+			return true;
382
+		default:
383
+			return false;
384
+		}
385
+	}
368
386
 
369
387
 	if (kvm_vcpu_trap_is_iabt(vcpu))
370
388
 		return false;