KVM: selftests: introduce P44V64 for z196 and EC12

Older machines like z196 and zEC12 do only support 44 bits of physical
addresses. Make this the default and check via IBC if we are on a later
machine. We then add P47V64 as an additional model.

Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Link: https://lore.kernel.org/kvm/20210701153853.33063-1-borntraeger@de.ibm.com/
Fixes: 1bc603af73 ("KVM: selftests: introduce P47V64 for s390x")

tools/testing/selftests/kvm/include/kvm_util.h

@@ -44,6 +44,7 @@ enum vm_guest_mode {
 	VM_MODE_P40V48_64K,
 	VM_MODE_PXXV48_4K,	/* For 48bits VA but ANY bits PA */
 	VM_MODE_P47V64_4K,
+	VM_MODE_P44V64_4K,
 	NUM_VM_MODES,
 };
 
@@ -61,7 +62,7 @@ enum vm_guest_mode {
 
 #elif defined(__s390x__)
 
-#define VM_MODE_DEFAULT			VM_MODE_P47V64_4K
+#define VM_MODE_DEFAULT			VM_MODE_P44V64_4K
 #define MIN_PAGE_SHIFT			12U
 #define ptes_per_page(page_size)	((page_size) / 16)
 

tools/testing/selftests/kvm/lib/guest_modes.c

@@ -22,6 +22,22 @@ void guest_modes_append_default(void)
 		}
 	}
 #endif
+#ifdef __s390x__
+	{
+		int kvm_fd, vm_fd;
+		struct kvm_s390_vm_cpu_processor info;
+
+		kvm_fd = open_kvm_dev_path_or_exit();
+		vm_fd = ioctl(kvm_fd, KVM_CREATE_VM, 0);
+		kvm_device_access(vm_fd, KVM_S390_VM_CPU_MODEL,
+				  KVM_S390_VM_CPU_PROCESSOR, &info, false);
+		close(vm_fd);
+		close(kvm_fd);
+		/* Starting with z13 we have 47bits of physical address */
+		if (info.ibc >= 0x30)
+			guest_mode_append(VM_MODE_P47V64_4K, true, true);
+	}
+#endif
 }
 
 void for_each_guest_mode(void (*func)(enum vm_guest_mode, void *), void *arg)

tools/testing/selftests/kvm/lib/kvm_util.c

@@ -176,6 +176,7 @@ const char *vm_guest_mode_string(uint32_t i)
 		[VM_MODE_P40V48_64K]	= "PA-bits:40,  VA-bits:48, 64K pages",
 		[VM_MODE_PXXV48_4K]	= "PA-bits:ANY, VA-bits:48,  4K pages",
 		[VM_MODE_P47V64_4K]	= "PA-bits:47,  VA-bits:64,  4K pages",
+		[VM_MODE_P44V64_4K]	= "PA-bits:44,  VA-bits:64,  4K pages",
 	};
 	_Static_assert(sizeof(strings)/sizeof(char *) == NUM_VM_MODES,
 		       "Missing new mode strings?");
@@ -194,6 +195,7 @@ const struct vm_guest_mode_params vm_guest_mode_params[] = {
 	{ 40, 48, 0x10000, 16 },
 	{  0,  0,  0x1000, 12 },
 	{ 47, 64,  0x1000, 12 },
+	{ 44, 64,  0x1000, 12 },
 };
 _Static_assert(sizeof(vm_guest_mode_params)/sizeof(struct vm_guest_mode_params) == NUM_VM_MODES,
 	       "Missing new mode params?");
@@ -282,6 +284,9 @@ struct kvm_vm *vm_create(enum vm_guest_mode mode, uint64_t phy_pages, int perm)
 	case VM_MODE_P47V64_4K:
 		vm->pgtable_levels = 5;
 		break;
+	case VM_MODE_P44V64_4K:
+		vm->pgtable_levels = 5;
+		break;
 	default:
 		TEST_FAIL("Unknown guest mode, mode: 0x%x", mode);
 	}