KVM: selftests: arm64: Add support for VM_MODE_P36V48_{4K,64K}

Some of the arm64 systems out there have an IPA space that is
positively tiny. Nonetheless, they make great KVM hosts.

Add support for 36bit IPA support with 4kB pages, which makes
some of the fruity machines happy. Whilst we're at it, add support
for 64kB pages as well, though these boxes have no support for it.

Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211227124809.1335409-6-maz@kernel.org

Author: Marc Zyngier

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

@@ -48,6 +48,8 @@ enum vm_guest_mode {
 	VM_MODE_PXXV48_4K,	/* For 48bits VA but ANY bits PA */
 	VM_MODE_P47V64_4K,
 	VM_MODE_P44V64_4K,
+	VM_MODE_P36V48_4K,
+	VM_MODE_P36V48_64K,
 	NUM_VM_MODES,
 };
 

tools/testing/selftests/kvm/lib/aarch64/processor.c

@@ -249,10 +249,12 @@ void aarch64_vcpu_setup(struct kvm_vm *vm, uint32_t vcpuid, struct kvm_vcpu_init
 	case VM_MODE_P52V48_64K:
 	case VM_MODE_P48V48_64K:
 	case VM_MODE_P40V48_64K:
+	case VM_MODE_P36V48_64K:
 		tcr_el1 |= 1ul << 14; /* TG0 = 64KB */
 		break;
 	case VM_MODE_P48V48_4K:
 	case VM_MODE_P40V48_4K:
+	case VM_MODE_P36V48_4K:
 		tcr_el1 |= 0ul << 14; /* TG0 = 4KB */
 		break;
 	default:
@@ -272,6 +274,10 @@ void aarch64_vcpu_setup(struct kvm_vm *vm, uint32_t vcpuid, struct kvm_vcpu_init
 	case VM_MODE_P40V48_64K:
 		tcr_el1 |= 2ul << 32; /* IPS = 40 bits */
 		break;
+	case VM_MODE_P36V48_4K:
+	case VM_MODE_P36V48_64K:
+		tcr_el1 |= 1ul << 32; /* IPS = 36 bits */
+		break;
 	default:
 		TEST_FAIL("Unknown guest mode, mode: 0x%x", vm->mode);
 	}

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

@@ -37,6 +37,10 @@ void guest_modes_append_default(void)
 			if (ps4k)
 				vm_mode_default = VM_MODE_P40V48_4K;
 		}
+		if (limit >= 36) {
+			guest_mode_append(VM_MODE_P36V48_4K, ps4k, ps4k);
+			guest_mode_append(VM_MODE_P36V48_64K, ps64k, ps64k);
+		}
 
 		/*
 		 * Pick the first supported IPA size if the default

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

@@ -172,6 +172,8 @@ const char *vm_guest_mode_string(uint32_t i)
 		[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",
+		[VM_MODE_P36V48_4K]	= "PA-bits:36,  VA-bits:48,  4K pages",
+		[VM_MODE_P36V48_64K]	= "PA-bits:36,  VA-bits:48, 64K pages",
 	};
 	_Static_assert(sizeof(strings)/sizeof(char *) == NUM_VM_MODES,
 		       "Missing new mode strings?");
@@ -191,6 +193,8 @@ const struct vm_guest_mode_params vm_guest_mode_params[] = {
 	[VM_MODE_PXXV48_4K]	= {  0,  0,  0x1000, 12 },
 	[VM_MODE_P47V64_4K]	= { 47, 64,  0x1000, 12 },
 	[VM_MODE_P44V64_4K]	= { 44, 64,  0x1000, 12 },
+	[VM_MODE_P36V48_4K]	= { 36, 48,  0x1000, 12 },
+	[VM_MODE_P36V48_64K]	= { 36, 48, 0x10000, 16 },
 };
 _Static_assert(sizeof(vm_guest_mode_params)/sizeof(struct vm_guest_mode_params) == NUM_VM_MODES,
 	       "Missing new mode params?");
@@ -252,9 +256,11 @@ struct kvm_vm *vm_create(enum vm_guest_mode mode, uint64_t phy_pages, int perm)
 		vm->pgtable_levels = 3;
 		break;
 	case VM_MODE_P40V48_4K:
+	case VM_MODE_P36V48_4K:
 		vm->pgtable_levels = 4;
 		break;
 	case VM_MODE_P40V48_64K:
+	case VM_MODE_P36V48_64K:
 		vm->pgtable_levels = 3;
 		break;
 	case VM_MODE_PXXV48_4K: