[PATCH 2/9] KVM: selftests: Add option to create 2M and 1G EPT mappings

[David Matlack <dmatlack@google.com>]

The current EPT mapping code in the selftests only supports mapping 4K
pages. This commit extends that support with an option to map at 2M or
1G. This will be used in a future commit to create large page mappings
to test eager page splitting.

No functional change intended.

Signed-off-by: David Matlack <dmatlack@google.com>
---
 tools/testing/selftests/kvm/lib/x86_64/vmx.c | 105 ++++++++++---------
 1 file changed, 57 insertions(+), 48 deletions(-)

diff --git a/tools/testing/selftests/kvm/lib/x86_64/vmx.c b/tools/testing/selftests/kvm/lib/x86_64/vmx.c
index d089d8b850b5..1fa2d1059ade 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/vmx.c
+++ b/tools/testing/selftests/kvm/lib/x86_64/vmx.c
@@ -392,27 +392,60 @@ void nested_vmx_check_supported(void)
 	}
 }
 
-void nested_pg_map(struct vmx_pages *vmx, struct kvm_vm *vm,
-		   uint64_t nested_paddr, uint64_t paddr)
+static void nested_create_upper_pte(struct kvm_vm *vm,
+				    struct eptPageTableEntry *pte,
+				    uint64_t nested_paddr,
+				    uint64_t paddr,
+				    int current_level,
+				    int target_level)
+{
+	if (!pte->readable) {
+		pte->writable = true;
+		pte->readable = true;
+		pte->executable = true;
+		pte->page_size = (current_level == target_level);
+		if (pte->page_size)
+			pte->address = paddr >> vm->page_shift;
+		else
+			pte->address = vm_alloc_page_table(vm) >> vm->page_shift;
+	} else {
+		/*
+		 * Entry already present.  Assert that the caller doesn't want
+		 * a hugepage at this level, and that there isn't a hugepage at
+		 * this level.
+		 */
+		TEST_ASSERT(current_level != target_level,
+			    "Cannot create hugepage at level: %u, nested_paddr: 0x%lx\n",
+			    current_level, nested_paddr);
+		TEST_ASSERT(!pte->page_size,
+			    "Cannot create page table at level: %u, nested_paddr: 0x%lx\n",
+			    current_level, nested_paddr);
+	}
+}
+
+
+void __nested_pg_map(struct vmx_pages *vmx, struct kvm_vm *vm,
+		     uint64_t nested_paddr, uint64_t paddr, int target_level)
 {
+	const uint64_t page_size = PG_LEVEL_SIZE(target_level);
+	struct eptPageTableEntry *pt;
 	uint16_t index[4];
-	struct eptPageTableEntry *pml4e;
 
 	TEST_ASSERT(vm->mode == VM_MODE_PXXV48_4K, "Attempt to use "
 		    "unknown or unsupported guest mode, mode: 0x%x", vm->mode);
 
-	TEST_ASSERT((nested_paddr % vm->page_size) == 0,
+	TEST_ASSERT((nested_paddr % page_size) == 0,
 		    "Nested physical address not on page boundary,\n"
-		    "  nested_paddr: 0x%lx vm->page_size: 0x%x",
-		    nested_paddr, vm->page_size);
+		    "  nested_paddr: 0x%lx page_size: 0x%lx",
+		    nested_paddr, page_size);
 	TEST_ASSERT((nested_paddr >> vm->page_shift) <= vm->max_gfn,
 		    "Physical address beyond beyond maximum supported,\n"
 		    "  nested_paddr: 0x%lx vm->max_gfn: 0x%lx vm->page_size: 0x%x",
 		    paddr, vm->max_gfn, vm->page_size);
-	TEST_ASSERT((paddr % vm->page_size) == 0,
+	TEST_ASSERT((paddr % page_size) == 0,
 		    "Physical address not on page boundary,\n"
-		    "  paddr: 0x%lx vm->page_size: 0x%x",
-		    paddr, vm->page_size);
+		    "  paddr: 0x%lx page_size: 0x%lx",
+		    paddr, page_size);
 	TEST_ASSERT((paddr >> vm->page_shift) <= vm->max_gfn,
 		    "Physical address beyond beyond maximum supported,\n"
 		    "  paddr: 0x%lx vm->max_gfn: 0x%lx vm->page_size: 0x%x",
@@ -423,49 +456,25 @@ void nested_pg_map(struct vmx_pages *vmx, struct kvm_vm *vm,
 	index[2] = (nested_paddr >> 30) & 0x1ffu;
 	index[3] = (nested_paddr >> 39) & 0x1ffu;
 
-	/* Allocate page directory pointer table if not present. */
-	pml4e = vmx->eptp_hva;
-	if (!pml4e[index[3]].readable) {
-		pml4e[index[3]].address = vm_alloc_page_table(vm) >> vm->page_shift;
-		pml4e[index[3]].writable = true;
-		pml4e[index[3]].readable = true;
-		pml4e[index[3]].executable = true;
-	}
+	pt = vmx->eptp_hva;
 
-	/* Allocate page directory table if not present. */
-	struct eptPageTableEntry *pdpe;
-	pdpe = addr_gpa2hva(vm, pml4e[index[3]].address * vm->page_size);
-	if (!pdpe[index[2]].readable) {
-		pdpe[index[2]].address = vm_alloc_page_table(vm) >> vm->page_shift;
-		pdpe[index[2]].writable = true;
-		pdpe[index[2]].readable = true;
-		pdpe[index[2]].executable = true;
-	}
+	for (int current_level = 3; current_level >= 0; current_level--) {
+		struct eptPageTableEntry *pte = &pt[index[current_level]];
 
-	/* Allocate page table if not present. */
-	struct eptPageTableEntry *pde;
-	pde = addr_gpa2hva(vm, pdpe[index[2]].address * vm->page_size);
-	if (!pde[index[1]].readable) {
-		pde[index[1]].address = vm_alloc_page_table(vm) >> vm->page_shift;
-		pde[index[1]].writable = true;
-		pde[index[1]].readable = true;
-		pde[index[1]].executable = true;
-	}
+		nested_create_upper_pte(vm, pte, nested_paddr, paddr,
+					current_level, target_level);
 
-	/* Fill in page table entry. */
-	struct eptPageTableEntry *pte;
-	pte = addr_gpa2hva(vm, pde[index[1]].address * vm->page_size);
-	pte[index[0]].address = paddr >> vm->page_shift;
-	pte[index[0]].writable = true;
-	pte[index[0]].readable = true;
-	pte[index[0]].executable = true;
+		if (pte->page_size)
+			break;
 
-	/*
-	 * For now mark these as accessed and dirty because the only
-	 * testcase we have needs that.  Can be reconsidered later.
-	 */
-	pte[index[0]].accessed = true;
-	pte[index[0]].dirty = true;
+		pt = addr_gpa2hva(vm, pte->address * vm->page_size);
+	}
+}
+
+void nested_pg_map(struct vmx_pages *vmx, struct kvm_vm *vm,
+		   uint64_t nested_paddr, uint64_t paddr)
+{
+	__nested_pg_map(vmx, vm, nested_paddr, paddr, PG_LEVEL_4K);
 }
 
 /*
-- 
2.36.0.464.gb9c8b46e94-goog