KVM: selftests: Change VM_MODE_PXXV48_4K to VM_MODE_PXXVYY_4K

Use 57-bit addresses with 5-level paging on hardware that supports
LA57. Continue to use 48-bit addresses with 4-level paging on hardware
that doesn't support LA57.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Jim Mattson <jmattson@google.com>
Link: https://patch.msgid.link/20251028225827.2269128-4-jmattson@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

Author: jsmattsonjr

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

@@ -177,7 +177,7 @@ enum vm_guest_mode {
 	VM_MODE_P40V48_4K,
 	VM_MODE_P40V48_16K,
 	VM_MODE_P40V48_64K,
-	VM_MODE_PXXV48_4K,	/* For 48bits VA but ANY bits PA */
+	VM_MODE_PXXVYY_4K,	/* For 48-bit or 57-bit VA, depending on host support */
 	VM_MODE_P47V64_4K,
 	VM_MODE_P44V64_4K,
 	VM_MODE_P36V48_4K,
@@ -219,7 +219,7 @@ extern enum vm_guest_mode vm_mode_default;
 
 #elif defined(__x86_64__)
 
-#define VM_MODE_DEFAULT			VM_MODE_PXXV48_4K
+#define VM_MODE_DEFAULT			VM_MODE_PXXVYY_4K
 #define MIN_PAGE_SHIFT			12U
 #define ptes_per_page(page_size)	((page_size) / 8)
 

tools/testing/selftests/kvm/include/x86/processor.h

@@ -1441,7 +1441,7 @@ enum pg_level {
 	PG_LEVEL_2M,
 	PG_LEVEL_1G,
 	PG_LEVEL_512G,
-	PG_LEVEL_NUM
+	PG_LEVEL_256T
 };
 
 #define PG_LEVEL_SHIFT(_level) ((_level - 1) * 9 + 12)

tools/testing/selftests/kvm/lib/arm64/processor.c

@@ -324,7 +324,7 @@ void aarch64_vcpu_setup(struct kvm_vcpu *vcpu, struct kvm_vcpu_init *init)
 
 	/* Configure base granule size */
 	switch (vm->mode) {
-	case VM_MODE_PXXV48_4K:
+	case VM_MODE_PXXVYY_4K:
 		TEST_FAIL("AArch64 does not support 4K sized pages "
 			  "with ANY-bit physical address ranges");
 	case VM_MODE_P52V48_64K:

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

@@ -201,7 +201,7 @@ const char *vm_guest_mode_string(uint32_t i)
 		[VM_MODE_P40V48_4K]	= "PA-bits:40,  VA-bits:48,  4K pages",
 		[VM_MODE_P40V48_16K]	= "PA-bits:40,  VA-bits:48, 16K pages",
 		[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_PXXVYY_4K]	= "PA-bits:ANY, VA-bits:48 or 57, 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",
@@ -228,7 +228,7 @@ const struct vm_guest_mode_params vm_guest_mode_params[] = {
 	[VM_MODE_P40V48_4K]	= { 40, 48,  0x1000, 12 },
 	[VM_MODE_P40V48_16K]	= { 40, 48,  0x4000, 14 },
 	[VM_MODE_P40V48_64K]	= { 40, 48, 0x10000, 16 },
-	[VM_MODE_PXXV48_4K]	= {  0,  0,  0x1000, 12 },
+	[VM_MODE_PXXVYY_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 },
@@ -310,24 +310,26 @@ struct kvm_vm *____vm_create(struct vm_shape shape)
 	case VM_MODE_P36V47_16K:
 		vm->pgtable_levels = 3;
 		break;
-	case VM_MODE_PXXV48_4K:
+	case VM_MODE_PXXVYY_4K:
 #ifdef __x86_64__
 		kvm_get_cpu_address_width(&vm->pa_bits, &vm->va_bits);
 		kvm_init_vm_address_properties(vm);
-		/*
-		 * Ignore KVM support for 5-level paging (vm->va_bits == 57),
-		 * it doesn't take effect unless a CR4.LA57 is set, which it
-		 * isn't for this mode (48-bit virtual address space).
-		 */
-		TEST_ASSERT(vm->va_bits == 48 || vm->va_bits == 57,
-			    "Linear address width (%d bits) not supported",
-			    vm->va_bits);
+
 		pr_debug("Guest physical address width detected: %d\n",
 			 vm->pa_bits);
-		vm->pgtable_levels = 4;
-		vm->va_bits = 48;
+		pr_debug("Guest virtual address width detected: %d\n",
+			 vm->va_bits);
+
+		if (vm->va_bits == 57) {
+			vm->pgtable_levels = 5;
+		} else {
+			TEST_ASSERT(vm->va_bits == 48,
+				    "Unexpected guest virtual address width: %d",
+				    vm->va_bits);
+			vm->pgtable_levels = 4;
+		}
 #else
-		TEST_FAIL("VM_MODE_PXXV48_4K not supported on non-x86 platforms");
+		TEST_FAIL("VM_MODE_PXXVYY_4K not supported on non-x86 platforms");
 #endif
 		break;
 	case VM_MODE_P47V64_4K:

tools/testing/selftests/kvm/lib/x86/processor.c

@@ -158,10 +158,10 @@ bool kvm_is_tdp_enabled(void)
 
 void virt_arch_pgd_alloc(struct kvm_vm *vm)
 {
-	TEST_ASSERT(vm->mode == VM_MODE_PXXV48_4K, "Attempt to use "
-		"unknown or unsupported guest mode, mode: 0x%x", vm->mode);
+	TEST_ASSERT(vm->mode == VM_MODE_PXXVYY_4K,
+		    "Unknown or unsupported guest mode: 0x%x", vm->mode);
 
-	/* If needed, create page map l4 table. */
+	/* If needed, create the top-level page table. */
 	if (!vm->pgd_created) {
 		vm->pgd = vm_alloc_page_table(vm);
 		vm->pgd_created = true;
@@ -221,8 +221,8 @@ void __virt_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr, int level)
 	uint64_t *pte = &vm->pgd;
 	int current_level;
 
-	TEST_ASSERT(vm->mode == VM_MODE_PXXV48_4K,
-		    "Unknown or unsupported guest mode, mode: 0x%x", vm->mode);
+	TEST_ASSERT(vm->mode == VM_MODE_PXXVYY_4K,
+		    "Unknown or unsupported guest mode: 0x%x", vm->mode);
 
 	TEST_ASSERT((vaddr % pg_size) == 0,
 		    "Virtual address not aligned,\n"
@@ -307,27 +307,28 @@ static bool vm_is_target_pte(uint64_t *pte, int *level, int current_level)
 uint64_t *__vm_get_page_table_entry(struct kvm_vm *vm, uint64_t vaddr,
 				    int *level)
 {
+	int va_width = 12 + (vm->pgtable_levels) * 9;
 	uint64_t *pte = &vm->pgd;
 	int current_level;
 
 	TEST_ASSERT(!vm->arch.is_pt_protected,
 		    "Walking page tables of protected guests is impossible");
 
-	TEST_ASSERT(*level >= PG_LEVEL_NONE && *level < PG_LEVEL_NUM,
+	TEST_ASSERT(*level >= PG_LEVEL_NONE && *level <= vm->pgtable_levels,
 		    "Invalid PG_LEVEL_* '%d'", *level);
 
-	TEST_ASSERT(vm->mode == VM_MODE_PXXV48_4K, "Attempt to use "
-		"unknown or unsupported guest mode, mode: 0x%x", vm->mode);
+	TEST_ASSERT(vm->mode == VM_MODE_PXXVYY_4K,
+		    "Unknown or unsupported guest mode: 0x%x", vm->mode);
 	TEST_ASSERT(sparsebit_is_set(vm->vpages_valid,
 		(vaddr >> vm->page_shift)),
 		"Invalid virtual address, vaddr: 0x%lx",
 		vaddr);
 	/*
-	 * Based on the mode check above there are 48 bits in the vaddr, so
-	 * shift 16 to sign extend the last bit (bit-47),
+	 * Check that the vaddr is a sign-extended va_width value.
 	 */
-	TEST_ASSERT(vaddr == (((int64_t)vaddr << 16) >> 16),
-		"Canonical check failed.  The virtual address is invalid.");
+	TEST_ASSERT(vaddr ==
+		    (((int64_t)vaddr << (64 - va_width) >> (64 - va_width))),
+		    "Canonical check failed.  The virtual address is invalid.");
 
 	for (current_level = vm->pgtable_levels;
 	     current_level > PG_LEVEL_4K;
@@ -520,7 +521,8 @@ static void vcpu_init_sregs(struct kvm_vm *vm, struct kvm_vcpu *vcpu)
 {
 	struct kvm_sregs sregs;
 
-	TEST_ASSERT_EQ(vm->mode, VM_MODE_PXXV48_4K);
+	TEST_ASSERT(vm->mode == VM_MODE_PXXVYY_4K,
+		    "Unknown or unsupported guest mode: 0x%x", vm->mode);
 
 	/* Set mode specific system register values. */
 	vcpu_sregs_get(vcpu, &sregs);
@@ -534,6 +536,8 @@ static void vcpu_init_sregs(struct kvm_vm *vm, struct kvm_vcpu *vcpu)
 	sregs.cr4 |= X86_CR4_PAE | X86_CR4_OSFXSR;
 	if (kvm_cpu_has(X86_FEATURE_XSAVE))
 		sregs.cr4 |= X86_CR4_OSXSAVE;
+	if (vm->pgtable_levels == 5)
+		sregs.cr4 |= X86_CR4_LA57;
 	sregs.efer |= (EFER_LME | EFER_LMA | EFER_NX);
 
 	kvm_seg_set_unusable(&sregs.ldt);

tools/testing/selftests/kvm/lib/x86/vmx.c

@@ -401,11 +401,11 @@ void __nested_pg_map(struct vmx_pages *vmx, struct kvm_vm *vm,
 	struct eptPageTableEntry *pt = vmx->eptp_hva, *pte;
 	uint16_t index;
 
-	TEST_ASSERT(vm->mode == VM_MODE_PXXV48_4K, "Attempt to use "
-		    "unknown or unsupported guest mode, mode: 0x%x", vm->mode);
+	TEST_ASSERT(vm->mode == VM_MODE_PXXVYY_4K,
+		    "Unknown or unsupported guest mode: 0x%x", vm->mode);
 
 	TEST_ASSERT((nested_paddr >> 48) == 0,
-		    "Nested physical address 0x%lx requires 5-level paging",
+		    "Nested physical address 0x%lx is > 48-bits and requires 5-level EPT",
 		    nested_paddr);
 	TEST_ASSERT((nested_paddr % page_size) == 0,
 		    "Nested physical address not on page boundary,\n"