1 files changed, 157 insertions, 0 deletions
diff --git a/pkg/ring0/pagetables/pagetables_test.go b/pkg/ring0/pagetables/pagetables_test.go
new file mode 100644
index 000000000..772f4fc5e
--- /dev/null
+++ b/pkg/ring0/pagetables/pagetables_test.go
@@ -0,0 +1,157 @@
+// Copyright 2018 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package pagetables
+
+import (
+	"testing"
+
+	"gvisor.dev/gvisor/pkg/usermem"
+)
+
+type mapping struct {
+	start  uintptr
+	length uintptr
+	addr   uintptr
+	opts   MapOpts
+}
+
+type checkVisitor struct {
+	expected []mapping // Input.
+	current  int       // Temporary.
+	found    []mapping // Output.
+	failed   string    // Output.
+}
+
+func (v *checkVisitor) visit(start uintptr, pte *PTE, align uintptr) bool {
+	v.found = append(v.found, mapping{
+		start:  start,
+		length: align + 1,
+		addr:   pte.Address(),
+		opts:   pte.Opts(),
+	})
+	if v.failed != "" {
+		// Don't keep looking for errors.
+		return false
+	}
+
+	if v.current >= len(v.expected) {
+		v.failed = "more mappings than expected"
+	} else if v.expected[v.current].start != start {
+		v.failed = "start didn't match expected"
+	} else if v.expected[v.current].length != (align + 1) {
+		v.failed = "end didn't match expected"
+	} else if v.expected[v.current].addr != pte.Address() {
+		v.failed = "address didn't match expected"
+	} else if v.expected[v.current].opts != pte.Opts() {
+		v.failed = "opts didn't match"
+	}
+	v.current++
+	return true
+}
+
+func (*checkVisitor) requiresAlloc() bool { return false }
+
+func (*checkVisitor) requiresSplit() bool { return false }
+
+func checkMappings(t *testing.T, pt *PageTables, m []mapping) {
+	// Iterate over all the mappings.
+	w := checkWalker{
+		pageTables: pt,
+		visitor: checkVisitor{
+			expected: m,
+		},
+	}
+	w.iterateRange(0, ^uintptr(0))
+
+	// Were we expected additional mappings?
+	if w.visitor.failed == "" && w.visitor.current != len(w.visitor.expected) {
+		w.visitor.failed = "insufficient mappings found"
+	}
+
+	// Emit a meaningful error message on failure.
+	if w.visitor.failed != "" {
+		t.Errorf("%s; got %#v, wanted %#v", w.visitor.failed, w.visitor.found, w.visitor.expected)
+	}
+}
+
+func TestUnmap(t *testing.T) {
+	pt := New(NewRuntimeAllocator())
+
+	// Map and unmap one entry.
+	pt.Map(0x400000, pteSize, MapOpts{AccessType: usermem.ReadWrite}, pteSize*42)
+	pt.Unmap(0x400000, pteSize)
+
+	checkMappings(t, pt, nil)
+}
+
+func TestReadOnly(t *testing.T) {
+	pt := New(NewRuntimeAllocator())
+
+	// Map one entry.
+	pt.Map(0x400000, pteSize, MapOpts{AccessType: usermem.Read}, pteSize*42)
+
+	checkMappings(t, pt, []mapping{
+		{0x400000, pteSize, pteSize * 42, MapOpts{AccessType: usermem.Read}},
+	})
+}
+
+func TestReadWrite(t *testing.T) {
+	pt := New(NewRuntimeAllocator())
+
+	// Map one entry.
+	pt.Map(0x400000, pteSize, MapOpts{AccessType: usermem.ReadWrite}, pteSize*42)
+
+	checkMappings(t, pt, []mapping{
+		{0x400000, pteSize, pteSize * 42, MapOpts{AccessType: usermem.ReadWrite}},
+	})
+}
+
+func TestSerialEntries(t *testing.T) {
+	pt := New(NewRuntimeAllocator())
+
+	// Map two sequential entries.
+	pt.Map(0x400000, pteSize, MapOpts{AccessType: usermem.ReadWrite}, pteSize*42)
+	pt.Map(0x401000, pteSize, MapOpts{AccessType: usermem.ReadWrite}, pteSize*47)
+
+	checkMappings(t, pt, []mapping{
+		{0x400000, pteSize, pteSize * 42, MapOpts{AccessType: usermem.ReadWrite}},
+		{0x401000, pteSize, pteSize * 47, MapOpts{AccessType: usermem.ReadWrite}},
+	})
+}
+
+func TestSpanningEntries(t *testing.T) {
+	pt := New(NewRuntimeAllocator())
+
+	// Span a pgd with two pages.
+	pt.Map(0x00007efffffff000, 2*pteSize, MapOpts{AccessType: usermem.Read}, pteSize*42)
+
+	checkMappings(t, pt, []mapping{
+		{0x00007efffffff000, pteSize, pteSize * 42, MapOpts{AccessType: usermem.Read}},
+		{0x00007f0000000000, pteSize, pteSize * 43, MapOpts{AccessType: usermem.Read}},
+	})
+}
+
+func TestSparseEntries(t *testing.T) {
+	pt := New(NewRuntimeAllocator())
+
+	// Map two entries in different pgds.
+	pt.Map(0x400000, pteSize, MapOpts{AccessType: usermem.ReadWrite}, pteSize*42)
+	pt.Map(0x00007f0000000000, pteSize, MapOpts{AccessType: usermem.Read}, pteSize*47)
+
+	checkMappings(t, pt, []mapping{
+		{0x400000, pteSize, pteSize * 42, MapOpts{AccessType: usermem.ReadWrite}},
+		{0x00007f0000000000, pteSize, pteSize * 47, MapOpts{AccessType: usermem.Read}},
+	})
+}