[PATCH v2 1/3] KVM: arm64: selftests: Support five-level stage-1 page tables

[Itaru Kitayama]

Add support for populating and walking five-level stage-1 page tables.
A five-level translation starts at architectural level -1, so extend
the page-table helpers and level validation accordingly.

This enables the page-table infrastructure required by 52-bit VA
configurations using the 4K translation granule.

Signed-off-by: Itaru Kitayama <itaru.kitayama@xxxxxxxxxxx>
Reviewed-by: Takayuki Okamoto <tokamoto@xxxxxxxxxxx>
---
 .../selftests/kvm/include/arm64/processor.h        |  1 +
 tools/testing/selftests/kvm/lib/arm64/processor.c  | 45 +++++++++++++++++++---
 2 files changed, 41 insertions(+), 5 deletions(-)

diff --git a/tools/testing/selftests/kvm/include/arm64/processor.h b/tools/testing/selftests/kvm/include/arm64/processor.h
index b8a902ba8573..7457503df956 100644
--- a/tools/testing/selftests/kvm/include/arm64/processor.h
+++ b/tools/testing/selftests/kvm/include/arm64/processor.h
@@ -113,6 +113,7 @@
 
 #define PTE_VALID		BIT(0)
 #define PGD_TYPE_TABLE		BIT(1)
+#define P4D_TYPE_TABLE		BIT(1)
 #define PUD_TYPE_TABLE		BIT(1)
 #define PMD_TYPE_TABLE		BIT(1)
 #define PTE_TYPE_PAGE		BIT(1)
diff --git a/tools/testing/selftests/kvm/lib/arm64/processor.c b/tools/testing/selftests/kvm/lib/arm64/processor.c
index 01325bf4d36f..b589368bf822 100644
--- a/tools/testing/selftests/kvm/lib/arm64/processor.c
+++ b/tools/testing/selftests/kvm/lib/arm64/processor.c
@@ -29,13 +29,25 @@ static u64 pgd_index(struct kvm_vm *vm, gva_t gva)
 	return (gva >> shift) & mask;
 }
 
+static u64 p4d_index(struct kvm_vm *vm, gva_t gva)
+{
+	unsigned int shift = 3 * (vm->page_shift - 3) + vm->page_shift;
+	u64 mask = (1UL << (vm->page_shift - 3)) - 1;
+
+	TEST_ASSERT(vm->mmu.pgtable_levels == 5,
+		    "Mode %d does not have 5 page table levels", vm->mode);
+
+	return (gva >> shift) & mask;
+}
+
 static u64 pud_index(struct kvm_vm *vm, gva_t gva)
 {
 	unsigned int shift = 2 * (vm->page_shift - 3) + vm->page_shift;
 	u64 mask = (1UL << (vm->page_shift - 3)) - 1;
 
-	TEST_ASSERT(vm->mmu.pgtable_levels == 4,
-		"Mode %d does not have 4 page table levels", vm->mode);
+	TEST_ASSERT(vm->mmu.pgtable_levels >= 4,
+		    "Mode %d does not have >= 4 page table levels",
+		    vm->mode);
 
 	return (gva >> shift) & mask;
 }
@@ -147,6 +159,12 @@ static void _virt_pg_map(struct kvm_vm *vm, gva_t gva, gpa_t gpa,
 				 PGD_TYPE_TABLE | PTE_VALID);
 
 	switch (vm->mmu.pgtable_levels) {
+	case 5:
+		ptep = addr_gpa2hva(vm, pte_addr(vm, *ptep)) + p4d_index(vm, gva) * 8;
+		if (!*ptep)
+			*ptep = addr_pte(vm, vm_alloc_page_table(vm),
+					 P4D_TYPE_TABLE | PTE_VALID);
+		/* fall through */
 	case 4:
 		ptep = addr_gpa2hva(vm, pte_addr(vm, *ptep)) + pud_index(vm, gva) * 8;
 		if (!*ptep)
@@ -163,7 +181,7 @@ static void _virt_pg_map(struct kvm_vm *vm, gva_t gva, gpa_t gpa,
 		ptep = addr_gpa2hva(vm, pte_addr(vm, *ptep)) + pte_index(vm, gva) * 8;
 		break;
 	default:
-		TEST_FAIL("Page table levels must be 2, 3, or 4");
+		TEST_FAIL("Page table levels must be 2, 3, 4, or 5");
 	}
 
 	pg_attr = PTE_AF | PTE_ATTRINDX(attr_idx) | PTE_TYPE_PAGE | PTE_VALID;
@@ -182,18 +200,35 @@ void virt_arch_pg_map(struct kvm_vm *vm, gva_t gva, gpa_t gpa)
 
 u64 *virt_get_pte_hva_at_level(struct kvm_vm *vm, gva_t gva, int level)
 {
+	int start_level = 4 - vm->mmu.pgtable_levels;
 	u64 *ptep;
 
+	TEST_ASSERT(level >= start_level && level <= 3,
+		    "Invalid translation level %d, valid range is %d-3",
+		    level, start_level);
+
 	if (!vm->mmu.pgd_created)
 		goto unmapped_gva;
 
 	ptep = addr_gpa2hva(vm, vm->mmu.pgd) + pgd_index(vm, gva) * 8;
 	if (!ptep)
 		goto unmapped_gva;
-	if (level == 0)
+	/*
+	 * Stage-1 translation starts at level -1 for a five-level page
+	 * table, and at levels 0, 1, or 2 for four-, three-, or two-level
+	 * page tables, respectively.
+	 */
+	if (level == start_level)
 		return ptep;
 
 	switch (vm->mmu.pgtable_levels) {
+	case 5:
+		ptep = addr_gpa2hva(vm, pte_addr(vm, *ptep)) + p4d_index(vm, gva) * 8;
+		if (!ptep)
+			goto unmapped_gva;
+		if (level == 0)
+			break;
+		/* fall through */
 	case 4:
 		ptep = addr_gpa2hva(vm, pte_addr(vm, *ptep)) + pud_index(vm, gva) * 8;
 		if (!ptep)
@@ -214,7 +249,7 @@ u64 *virt_get_pte_hva_at_level(struct kvm_vm *vm, gva_t gva, int level)
 			goto unmapped_gva;
 		break;
 	default:
-		TEST_FAIL("Page table levels must be 2, 3, or 4");
+		TEST_FAIL("Page table levels must be 2, 3, 4, or 5");
 	}
 
 	return ptep;

-- 
2.43.0