Merge release-20201216.0-94-ge74aa25e2 (automated)

4 files changed, 0 insertions, 1020 deletions

diff --git a/pkg/sentry/platform/ring0/pagetables/walker_empty.go b/pkg/sentry/platform/ring0/pagetables/walker_empty.go
deleted file mode 100644
index 417784e17..000000000
--- a/pkg/sentry/platform/ring0/pagetables/walker_empty.go
+++ /dev/null
@@ -1,255 +0,0 @@
-package pagetables
-
-// Walker walks page tables.
-type emptyWalker struct {
-	// pageTables are the tables to walk.
-	pageTables *PageTables
-
-	// Visitor is the set of arguments.
-	visitor emptyVisitor
-}
-
-// iterateRange iterates over all appropriate levels of page tables for the given range.
-//
-// If requiresAlloc is true, then Set _must_ be called on all given PTEs. The
-// exception is super pages. If a valid super page (huge or jumbo) cannot be
-// installed, then the walk will continue to individual entries.
-//
-// This algorithm will attempt to maximize the use of super pages whenever
-// possible. Whether a super page is provided will be clear through the range
-// provided in the callback.
-//
-// Note that if requiresAlloc is true, then no gaps will be present. However,
-// if alloc is not set, then the iteration will likely be full of gaps.
-//
-// Note that this function should generally be avoided in favor of Map, Unmap,
-// etc. when not necessary.
-//
-// Precondition: start must be page-aligned.
-//
-// Precondition: start must be less than end.
-//
-// Precondition: If requiresAlloc is true, then start and end should not span
-// non-canonical ranges. If they do, a panic will result.
-//
-//go:nosplit
-func (w *emptyWalker) iterateRange(start, end uintptr) {
-	if start%pteSize != 0 {
-		panic("unaligned start")
-	}
-	if end < start {
-		panic("start > end")
-	}
-	if start < lowerTop {
-		if end <= lowerTop {
-			w.iterateRangeCanonical(start, end)
-		} else if end > lowerTop && end <= upperBottom {
-			if w.visitor.requiresAlloc() {
-				panic("alloc spans non-canonical range")
-			}
-			w.iterateRangeCanonical(start, lowerTop)
-		} else {
-			if w.visitor.requiresAlloc() {
-				panic("alloc spans non-canonical range")
-			}
-			w.iterateRangeCanonical(start, lowerTop)
-			w.iterateRangeCanonical(upperBottom, end)
-		}
-	} else if start < upperBottom {
-		if end <= upperBottom {
-			if w.visitor.requiresAlloc() {
-				panic("alloc spans non-canonical range")
-			}
-		} else {
-			if w.visitor.requiresAlloc() {
-				panic("alloc spans non-canonical range")
-			}
-			w.iterateRangeCanonical(upperBottom, end)
-		}
-	} else {
-		w.iterateRangeCanonical(start, end)
-	}
-}
-
-// next returns the next address quantized by the given size.
-//
-//go:nosplit
-func emptynext(start uintptr, size uintptr) uintptr {
-	start &= ^(size - 1)
-	start += size
-	return start
-}
-
-// iterateRangeCanonical walks a canonical range.
-//
-//go:nosplit
-func (w *emptyWalker) iterateRangeCanonical(start, end uintptr) {
-	for pgdIndex := uint16((start & pgdMask) >> pgdShift); start < end && pgdIndex < entriesPerPage; pgdIndex++ {
-		var (
-			pgdEntry   = &w.pageTables.root[pgdIndex]
-			pudEntries *PTEs
-		)
-		if !pgdEntry.Valid() {
-			if !w.visitor.requiresAlloc() {
-
-				start = emptynext(start, pgdSize)
-				continue
-			}
-
-			pudEntries = w.pageTables.Allocator.NewPTEs()
-			pgdEntry.setPageTable(w.pageTables, pudEntries)
-		} else {
-			pudEntries = w.pageTables.Allocator.LookupPTEs(pgdEntry.Address())
-		}
-
-		clearPUDEntries := uint16(0)
-
-		for pudIndex := uint16((start & pudMask) >> pudShift); start < end && pudIndex < entriesPerPage; pudIndex++ {
-			var (
-				pudEntry   = &pudEntries[pudIndex]
-				pmdEntries *PTEs
-			)
-			if !pudEntry.Valid() {
-				if !w.visitor.requiresAlloc() {
-
-					clearPUDEntries++
-					start = emptynext(start, pudSize)
-					continue
-				}
-
-				if start&(pudSize-1) == 0 && end-start >= pudSize {
-					pudEntry.SetSuper()
-					w.visitor.visit(uintptr(start), pudEntry, pudSize-1)
-					if pudEntry.Valid() {
-						start = emptynext(start, pudSize)
-						continue
-					}
-				}
-
-				pmdEntries = w.pageTables.Allocator.NewPTEs()
-				pudEntry.setPageTable(w.pageTables, pmdEntries)
-
-			} else if pudEntry.IsSuper() {
-
-				if w.visitor.requiresSplit() && (start&(pudSize-1) != 0 || end < emptynext(start, pudSize)) {
-
-					pmdEntries = w.pageTables.Allocator.NewPTEs()
-					for index := uint16(0); index < entriesPerPage; index++ {
-						pmdEntries[index].SetSuper()
-						pmdEntries[index].Set(
-							pudEntry.Address()+(pmdSize*uintptr(index)),
-							pudEntry.Opts())
-					}
-					pudEntry.setPageTable(w.pageTables, pmdEntries)
-				} else {
-
-					w.visitor.visit(uintptr(start), pudEntry, pudSize-1)
-
-					if !pudEntry.Valid() {
-						clearPUDEntries++
-					}
-
-					start = emptynext(start, pudSize)
-					continue
-				}
-			} else {
-				pmdEntries = w.pageTables.Allocator.LookupPTEs(pudEntry.Address())
-			}
-
-			clearPMDEntries := uint16(0)
-
-			for pmdIndex := uint16((start & pmdMask) >> pmdShift); start < end && pmdIndex < entriesPerPage; pmdIndex++ {
-				var (
-					pmdEntry   = &pmdEntries[pmdIndex]
-					pteEntries *PTEs
-				)
-				if !pmdEntry.Valid() {
-					if !w.visitor.requiresAlloc() {
-
-						clearPMDEntries++
-						start = emptynext(start, pmdSize)
-						continue
-					}
-
-					if start&(pmdSize-1) == 0 && end-start >= pmdSize {
-						pmdEntry.SetSuper()
-						w.visitor.visit(uintptr(start), pmdEntry, pmdSize-1)
-						if pmdEntry.Valid() {
-							start = emptynext(start, pmdSize)
-							continue
-						}
-					}
-
-					pteEntries = w.pageTables.Allocator.NewPTEs()
-					pmdEntry.setPageTable(w.pageTables, pteEntries)
-
-				} else if pmdEntry.IsSuper() {
-
-					if w.visitor.requiresSplit() && (start&(pmdSize-1) != 0 || end < emptynext(start, pmdSize)) {
-
-						pteEntries = w.pageTables.Allocator.NewPTEs()
-						for index := uint16(0); index < entriesPerPage; index++ {
-							pteEntries[index].Set(
-								pmdEntry.Address()+(pteSize*uintptr(index)),
-								pmdEntry.Opts())
-						}
-						pmdEntry.setPageTable(w.pageTables, pteEntries)
-					} else {
-
-						w.visitor.visit(uintptr(start), pmdEntry, pmdSize-1)
-
-						if !pmdEntry.Valid() {
-							clearPMDEntries++
-						}
-
-						start = emptynext(start, pmdSize)
-						continue
-					}
-				} else {
-					pteEntries = w.pageTables.Allocator.LookupPTEs(pmdEntry.Address())
-				}
-
-				clearPTEEntries := uint16(0)
-
-				for pteIndex := uint16((start & pteMask) >> pteShift); start < end && pteIndex < entriesPerPage; pteIndex++ {
-					var (
-						pteEntry = &pteEntries[pteIndex]
-					)
-					if !pteEntry.Valid() && !w.visitor.requiresAlloc() {
-						clearPTEEntries++
-						start += pteSize
-						continue
-					}
-
-					w.visitor.visit(uintptr(start), pteEntry, pteSize-1)
-					if !pteEntry.Valid() {
-						if w.visitor.requiresAlloc() {
-							panic("PTE not set after iteration with requiresAlloc!")
-						}
-						clearPTEEntries++
-					}
-
-					start += pteSize
-					continue
-				}
-
-				if clearPTEEntries == entriesPerPage {
-					pmdEntry.Clear()
-					w.pageTables.Allocator.FreePTEs(pteEntries)
-					clearPMDEntries++
-				}
-			}
-
-			if clearPMDEntries == entriesPerPage {
-				pudEntry.Clear()
-				w.pageTables.Allocator.FreePTEs(pmdEntries)
-				clearPUDEntries++
-			}
-		}
-
-		if clearPUDEntries == entriesPerPage {
-			pgdEntry.Clear()
-			w.pageTables.Allocator.FreePTEs(pudEntries)
-		}
-	}
-}
diff --git a/pkg/sentry/platform/ring0/pagetables/walker_lookup.go b/pkg/sentry/platform/ring0/pagetables/walker_lookup.go
deleted file mode 100644
index 906c9c50f..000000000
--- a/pkg/sentry/platform/ring0/pagetables/walker_lookup.go
+++ /dev/null
@@ -1,255 +0,0 @@
-package pagetables
-
-// Walker walks page tables.
-type lookupWalker struct {
-	// pageTables are the tables to walk.
-	pageTables *PageTables
-
-	// Visitor is the set of arguments.
-	visitor lookupVisitor
-}
-
-// iterateRange iterates over all appropriate levels of page tables for the given range.
-//
-// If requiresAlloc is true, then Set _must_ be called on all given PTEs. The
-// exception is super pages. If a valid super page (huge or jumbo) cannot be
-// installed, then the walk will continue to individual entries.
-//
-// This algorithm will attempt to maximize the use of super pages whenever
-// possible. Whether a super page is provided will be clear through the range
-// provided in the callback.
-//
-// Note that if requiresAlloc is true, then no gaps will be present. However,
-// if alloc is not set, then the iteration will likely be full of gaps.
-//
-// Note that this function should generally be avoided in favor of Map, Unmap,
-// etc. when not necessary.
-//
-// Precondition: start must be page-aligned.
-//
-// Precondition: start must be less than end.
-//
-// Precondition: If requiresAlloc is true, then start and end should not span
-// non-canonical ranges. If they do, a panic will result.
-//
-//go:nosplit
-func (w *lookupWalker) iterateRange(start, end uintptr) {
-	if start%pteSize != 0 {
-		panic("unaligned start")
-	}
-	if end < start {
-		panic("start > end")
-	}
-	if start < lowerTop {
-		if end <= lowerTop {
-			w.iterateRangeCanonical(start, end)
-		} else if end > lowerTop && end <= upperBottom {
-			if w.visitor.requiresAlloc() {
-				panic("alloc spans non-canonical range")
-			}
-			w.iterateRangeCanonical(start, lowerTop)
-		} else {
-			if w.visitor.requiresAlloc() {
-				panic("alloc spans non-canonical range")
-			}
-			w.iterateRangeCanonical(start, lowerTop)
-			w.iterateRangeCanonical(upperBottom, end)
-		}
-	} else if start < upperBottom {
-		if end <= upperBottom {
-			if w.visitor.requiresAlloc() {
-				panic("alloc spans non-canonical range")
-			}
-		} else {
-			if w.visitor.requiresAlloc() {
-				panic("alloc spans non-canonical range")
-			}
-			w.iterateRangeCanonical(upperBottom, end)
-		}
-	} else {
-		w.iterateRangeCanonical(start, end)
-	}
-}
-
-// next returns the next address quantized by the given size.
-//
-//go:nosplit
-func lookupnext(start uintptr, size uintptr) uintptr {
-	start &= ^(size - 1)
-	start += size
-	return start
-}
-
-// iterateRangeCanonical walks a canonical range.
-//
-//go:nosplit
-func (w *lookupWalker) iterateRangeCanonical(start, end uintptr) {
-	for pgdIndex := uint16((start & pgdMask) >> pgdShift); start < end && pgdIndex < entriesPerPage; pgdIndex++ {
-		var (
-			pgdEntry   = &w.pageTables.root[pgdIndex]
-			pudEntries *PTEs
-		)
-		if !pgdEntry.Valid() {
-			if !w.visitor.requiresAlloc() {
-
-				start = lookupnext(start, pgdSize)
-				continue
-			}
-
-			pudEntries = w.pageTables.Allocator.NewPTEs()
-			pgdEntry.setPageTable(w.pageTables, pudEntries)
-		} else {
-			pudEntries = w.pageTables.Allocator.LookupPTEs(pgdEntry.Address())
-		}
-
-		clearPUDEntries := uint16(0)
-
-		for pudIndex := uint16((start & pudMask) >> pudShift); start < end && pudIndex < entriesPerPage; pudIndex++ {
-			var (
-				pudEntry   = &pudEntries[pudIndex]
-				pmdEntries *PTEs
-			)
-			if !pudEntry.Valid() {
-				if !w.visitor.requiresAlloc() {
-
-					clearPUDEntries++
-					start = lookupnext(start, pudSize)
-					continue
-				}
-
-				if start&(pudSize-1) == 0 && end-start >= pudSize {
-					pudEntry.SetSuper()
-					w.visitor.visit(uintptr(start), pudEntry, pudSize-1)
-					if pudEntry.Valid() {
-						start = lookupnext(start, pudSize)
-						continue
-					}
-				}
-
-				pmdEntries = w.pageTables.Allocator.NewPTEs()
-				pudEntry.setPageTable(w.pageTables, pmdEntries)
-
-			} else if pudEntry.IsSuper() {
-
-				if w.visitor.requiresSplit() && (start&(pudSize-1) != 0 || end < lookupnext(start, pudSize)) {
-
-					pmdEntries = w.pageTables.Allocator.NewPTEs()
-					for index := uint16(0); index < entriesPerPage; index++ {
-						pmdEntries[index].SetSuper()
-						pmdEntries[index].Set(
-							pudEntry.Address()+(pmdSize*uintptr(index)),
-							pudEntry.Opts())
-					}
-					pudEntry.setPageTable(w.pageTables, pmdEntries)
-				} else {
-
-					w.visitor.visit(uintptr(start), pudEntry, pudSize-1)
-
-					if !pudEntry.Valid() {
-						clearPUDEntries++
-					}
-
-					start = lookupnext(start, pudSize)
-					continue
-				}
-			} else {
-				pmdEntries = w.pageTables.Allocator.LookupPTEs(pudEntry.Address())
-			}
-
-			clearPMDEntries := uint16(0)
-
-			for pmdIndex := uint16((start & pmdMask) >> pmdShift); start < end && pmdIndex < entriesPerPage; pmdIndex++ {
-				var (
-					pmdEntry   = &pmdEntries[pmdIndex]
-					pteEntries *PTEs
-				)
-				if !pmdEntry.Valid() {
-					if !w.visitor.requiresAlloc() {
-
-						clearPMDEntries++
-						start = lookupnext(start, pmdSize)
-						continue
-					}
-
-					if start&(pmdSize-1) == 0 && end-start >= pmdSize {
-						pmdEntry.SetSuper()
-						w.visitor.visit(uintptr(start), pmdEntry, pmdSize-1)
-						if pmdEntry.Valid() {
-							start = lookupnext(start, pmdSize)
-							continue
-						}
-					}
-
-					pteEntries = w.pageTables.Allocator.NewPTEs()
-					pmdEntry.setPageTable(w.pageTables, pteEntries)
-
-				} else if pmdEntry.IsSuper() {
-
-					if w.visitor.requiresSplit() && (start&(pmdSize-1) != 0 || end < lookupnext(start, pmdSize)) {
-
-						pteEntries = w.pageTables.Allocator.NewPTEs()
-						for index := uint16(0); index < entriesPerPage; index++ {
-							pteEntries[index].Set(
-								pmdEntry.Address()+(pteSize*uintptr(index)),
-								pmdEntry.Opts())
-						}
-						pmdEntry.setPageTable(w.pageTables, pteEntries)
-					} else {
-
-						w.visitor.visit(uintptr(start), pmdEntry, pmdSize-1)
-
-						if !pmdEntry.Valid() {
-							clearPMDEntries++
-						}
-
-						start = lookupnext(start, pmdSize)
-						continue
-					}
-				} else {
-					pteEntries = w.pageTables.Allocator.LookupPTEs(pmdEntry.Address())
-				}
-
-				clearPTEEntries := uint16(0)
-
-				for pteIndex := uint16((start & pteMask) >> pteShift); start < end && pteIndex < entriesPerPage; pteIndex++ {
-					var (
-						pteEntry = &pteEntries[pteIndex]
-					)
-					if !pteEntry.Valid() && !w.visitor.requiresAlloc() {
-						clearPTEEntries++
-						start += pteSize
-						continue
-					}
-
-					w.visitor.visit(uintptr(start), pteEntry, pteSize-1)
-					if !pteEntry.Valid() {
-						if w.visitor.requiresAlloc() {
-							panic("PTE not set after iteration with requiresAlloc!")
-						}
-						clearPTEEntries++
-					}
-
-					start += pteSize
-					continue
-				}
-
-				if clearPTEEntries == entriesPerPage {
-					pmdEntry.Clear()
-					w.pageTables.Allocator.FreePTEs(pteEntries)
-					clearPMDEntries++
-				}
-			}
-
-			if clearPMDEntries == entriesPerPage {
-				pudEntry.Clear()
-				w.pageTables.Allocator.FreePTEs(pmdEntries)
-				clearPUDEntries++
-			}
-		}
-
-		if clearPUDEntries == entriesPerPage {
-			pgdEntry.Clear()
-			w.pageTables.Allocator.FreePTEs(pudEntries)
-		}
-	}
-}
diff --git a/pkg/sentry/platform/ring0/pagetables/walker_map.go b/pkg/sentry/platform/ring0/pagetables/walker_map.go
deleted file mode 100644
index 61ee3c825..000000000
--- a/pkg/sentry/platform/ring0/pagetables/walker_map.go
+++ /dev/null
@@ -1,255 +0,0 @@
-package pagetables
-
-// Walker walks page tables.
-type mapWalker struct {
-	// pageTables are the tables to walk.
-	pageTables *PageTables
-
-	// Visitor is the set of arguments.
-	visitor mapVisitor
-}
-
-// iterateRange iterates over all appropriate levels of page tables for the given range.
-//
-// If requiresAlloc is true, then Set _must_ be called on all given PTEs. The
-// exception is super pages. If a valid super page (huge or jumbo) cannot be
-// installed, then the walk will continue to individual entries.
-//
-// This algorithm will attempt to maximize the use of super pages whenever
-// possible. Whether a super page is provided will be clear through the range
-// provided in the callback.
-//
-// Note that if requiresAlloc is true, then no gaps will be present. However,
-// if alloc is not set, then the iteration will likely be full of gaps.
-//
-// Note that this function should generally be avoided in favor of Map, Unmap,
-// etc. when not necessary.
-//
-// Precondition: start must be page-aligned.
-//
-// Precondition: start must be less than end.
-//
-// Precondition: If requiresAlloc is true, then start and end should not span
-// non-canonical ranges. If they do, a panic will result.
-//
-//go:nosplit
-func (w *mapWalker) iterateRange(start, end uintptr) {
-	if start%pteSize != 0 {
-		panic("unaligned start")
-	}
-	if end < start {
-		panic("start > end")
-	}
-	if start < lowerTop {
-		if end <= lowerTop {
-			w.iterateRangeCanonical(start, end)
-		} else if end > lowerTop && end <= upperBottom {
-			if w.visitor.requiresAlloc() {
-				panic("alloc spans non-canonical range")
-			}
-			w.iterateRangeCanonical(start, lowerTop)
-		} else {
-			if w.visitor.requiresAlloc() {
-				panic("alloc spans non-canonical range")
-			}
-			w.iterateRangeCanonical(start, lowerTop)
-			w.iterateRangeCanonical(upperBottom, end)
-		}
-	} else if start < upperBottom {
-		if end <= upperBottom {
-			if w.visitor.requiresAlloc() {
-				panic("alloc spans non-canonical range")
-			}
-		} else {
-			if w.visitor.requiresAlloc() {
-				panic("alloc spans non-canonical range")
-			}
-			w.iterateRangeCanonical(upperBottom, end)
-		}
-	} else {
-		w.iterateRangeCanonical(start, end)
-	}
-}
-
-// next returns the next address quantized by the given size.
-//
-//go:nosplit
-func mapnext(start uintptr, size uintptr) uintptr {
-	start &= ^(size - 1)
-	start += size
-	return start
-}
-
-// iterateRangeCanonical walks a canonical range.
-//
-//go:nosplit
-func (w *mapWalker) iterateRangeCanonical(start, end uintptr) {
-	for pgdIndex := uint16((start & pgdMask) >> pgdShift); start < end && pgdIndex < entriesPerPage; pgdIndex++ {
-		var (
-			pgdEntry   = &w.pageTables.root[pgdIndex]
-			pudEntries *PTEs
-		)
-		if !pgdEntry.Valid() {
-			if !w.visitor.requiresAlloc() {
-
-				start = mapnext(start, pgdSize)
-				continue
-			}
-
-			pudEntries = w.pageTables.Allocator.NewPTEs()
-			pgdEntry.setPageTable(w.pageTables, pudEntries)
-		} else {
-			pudEntries = w.pageTables.Allocator.LookupPTEs(pgdEntry.Address())
-		}
-
-		clearPUDEntries := uint16(0)
-
-		for pudIndex := uint16((start & pudMask) >> pudShift); start < end && pudIndex < entriesPerPage; pudIndex++ {
-			var (
-				pudEntry   = &pudEntries[pudIndex]
-				pmdEntries *PTEs
-			)
-			if !pudEntry.Valid() {
-				if !w.visitor.requiresAlloc() {
-
-					clearPUDEntries++
-					start = mapnext(start, pudSize)
-					continue
-				}
-
-				if start&(pudSize-1) == 0 && end-start >= pudSize {
-					pudEntry.SetSuper()
-					w.visitor.visit(uintptr(start), pudEntry, pudSize-1)
-					if pudEntry.Valid() {
-						start = mapnext(start, pudSize)
-						continue
-					}
-				}
-
-				pmdEntries = w.pageTables.Allocator.NewPTEs()
-				pudEntry.setPageTable(w.pageTables, pmdEntries)
-
-			} else if pudEntry.IsSuper() {
-
-				if w.visitor.requiresSplit() && (start&(pudSize-1) != 0 || end < mapnext(start, pudSize)) {
-
-					pmdEntries = w.pageTables.Allocator.NewPTEs()
-					for index := uint16(0); index < entriesPerPage; index++ {
-						pmdEntries[index].SetSuper()
-						pmdEntries[index].Set(
-							pudEntry.Address()+(pmdSize*uintptr(index)),
-							pudEntry.Opts())
-					}
-					pudEntry.setPageTable(w.pageTables, pmdEntries)
-				} else {
-
-					w.visitor.visit(uintptr(start), pudEntry, pudSize-1)
-
-					if !pudEntry.Valid() {
-						clearPUDEntries++
-					}
-
-					start = mapnext(start, pudSize)
-					continue
-				}
-			} else {
-				pmdEntries = w.pageTables.Allocator.LookupPTEs(pudEntry.Address())
-			}
-
-			clearPMDEntries := uint16(0)
-
-			for pmdIndex := uint16((start & pmdMask) >> pmdShift); start < end && pmdIndex < entriesPerPage; pmdIndex++ {
-				var (
-					pmdEntry   = &pmdEntries[pmdIndex]
-					pteEntries *PTEs
-				)
-				if !pmdEntry.Valid() {
-					if !w.visitor.requiresAlloc() {
-
-						clearPMDEntries++
-						start = mapnext(start, pmdSize)
-						continue
-					}
-
-					if start&(pmdSize-1) == 0 && end-start >= pmdSize {
-						pmdEntry.SetSuper()
-						w.visitor.visit(uintptr(start), pmdEntry, pmdSize-1)
-						if pmdEntry.Valid() {
-							start = mapnext(start, pmdSize)
-							continue
-						}
-					}
-
-					pteEntries = w.pageTables.Allocator.NewPTEs()
-					pmdEntry.setPageTable(w.pageTables, pteEntries)
-
-				} else if pmdEntry.IsSuper() {
-
-					if w.visitor.requiresSplit() && (start&(pmdSize-1) != 0 || end < mapnext(start, pmdSize)) {
-
-						pteEntries = w.pageTables.Allocator.NewPTEs()
-						for index := uint16(0); index < entriesPerPage; index++ {
-							pteEntries[index].Set(
-								pmdEntry.Address()+(pteSize*uintptr(index)),
-								pmdEntry.Opts())
-						}
-						pmdEntry.setPageTable(w.pageTables, pteEntries)
-					} else {
-
-						w.visitor.visit(uintptr(start), pmdEntry, pmdSize-1)
-
-						if !pmdEntry.Valid() {
-							clearPMDEntries++
-						}
-
-						start = mapnext(start, pmdSize)
-						continue
-					}
-				} else {
-					pteEntries = w.pageTables.Allocator.LookupPTEs(pmdEntry.Address())
-				}
-
-				clearPTEEntries := uint16(0)
-
-				for pteIndex := uint16((start & pteMask) >> pteShift); start < end && pteIndex < entriesPerPage; pteIndex++ {
-					var (
-						pteEntry = &pteEntries[pteIndex]
-					)
-					if !pteEntry.Valid() && !w.visitor.requiresAlloc() {
-						clearPTEEntries++
-						start += pteSize
-						continue
-					}
-
-					w.visitor.visit(uintptr(start), pteEntry, pteSize-1)
-					if !pteEntry.Valid() {
-						if w.visitor.requiresAlloc() {
-							panic("PTE not set after iteration with requiresAlloc!")
-						}
-						clearPTEEntries++
-					}
-
-					start += pteSize
-					continue
-				}
-
-				if clearPTEEntries == entriesPerPage {
-					pmdEntry.Clear()
-					w.pageTables.Allocator.FreePTEs(pteEntries)
-					clearPMDEntries++
-				}
-			}
-
-			if clearPMDEntries == entriesPerPage {
-				pudEntry.Clear()
-				w.pageTables.Allocator.FreePTEs(pmdEntries)
-				clearPUDEntries++
-			}
-		}
-
-		if clearPUDEntries == entriesPerPage {
-			pgdEntry.Clear()
-			w.pageTables.Allocator.FreePTEs(pudEntries)
-		}
-	}
-}
diff --git a/pkg/sentry/platform/ring0/pagetables/walker_unmap.go b/pkg/sentry/platform/ring0/pagetables/walker_unmap.go
deleted file mode 100644
index be2aa0ce4..000000000
--- a/pkg/sentry/platform/ring0/pagetables/walker_unmap.go
+++ /dev/null
@@ -1,255 +0,0 @@
-package pagetables
-
-// Walker walks page tables.
-type unmapWalker struct {
-	// pageTables are the tables to walk.
-	pageTables *PageTables
-
-	// Visitor is the set of arguments.
-	visitor unmapVisitor
-}
-
-// iterateRange iterates over all appropriate levels of page tables for the given range.
-//
-// If requiresAlloc is true, then Set _must_ be called on all given PTEs. The
-// exception is super pages. If a valid super page (huge or jumbo) cannot be
-// installed, then the walk will continue to individual entries.
-//
-// This algorithm will attempt to maximize the use of super pages whenever
-// possible. Whether a super page is provided will be clear through the range
-// provided in the callback.
-//
-// Note that if requiresAlloc is true, then no gaps will be present. However,
-// if alloc is not set, then the iteration will likely be full of gaps.
-//
-// Note that this function should generally be avoided in favor of Map, Unmap,
-// etc. when not necessary.
-//
-// Precondition: start must be page-aligned.
-//
-// Precondition: start must be less than end.
-//
-// Precondition: If requiresAlloc is true, then start and end should not span
-// non-canonical ranges. If they do, a panic will result.
-//
-//go:nosplit
-func (w *unmapWalker) iterateRange(start, end uintptr) {
-	if start%pteSize != 0 {
-		panic("unaligned start")
-	}
-	if end < start {
-		panic("start > end")
-	}
-	if start < lowerTop {
-		if end <= lowerTop {
-			w.iterateRangeCanonical(start, end)
-		} else if end > lowerTop && end <= upperBottom {
-			if w.visitor.requiresAlloc() {
-				panic("alloc spans non-canonical range")
-			}
-			w.iterateRangeCanonical(start, lowerTop)
-		} else {
-			if w.visitor.requiresAlloc() {
-				panic("alloc spans non-canonical range")
-			}
-			w.iterateRangeCanonical(start, lowerTop)
-			w.iterateRangeCanonical(upperBottom, end)
-		}
-	} else if start < upperBottom {
-		if end <= upperBottom {
-			if w.visitor.requiresAlloc() {
-				panic("alloc spans non-canonical range")
-			}
-		} else {
-			if w.visitor.requiresAlloc() {
-				panic("alloc spans non-canonical range")
-			}
-			w.iterateRangeCanonical(upperBottom, end)
-		}
-	} else {
-		w.iterateRangeCanonical(start, end)
-	}
-}
-
-// next returns the next address quantized by the given size.
-//
-//go:nosplit
-func unmapnext(start uintptr, size uintptr) uintptr {
-	start &= ^(size - 1)
-	start += size
-	return start
-}
-
-// iterateRangeCanonical walks a canonical range.
-//
-//go:nosplit
-func (w *unmapWalker) iterateRangeCanonical(start, end uintptr) {
-	for pgdIndex := uint16((start & pgdMask) >> pgdShift); start < end && pgdIndex < entriesPerPage; pgdIndex++ {
-		var (
-			pgdEntry   = &w.pageTables.root[pgdIndex]
-			pudEntries *PTEs
-		)
-		if !pgdEntry.Valid() {
-			if !w.visitor.requiresAlloc() {
-
-				start = unmapnext(start, pgdSize)
-				continue
-			}
-
-			pudEntries = w.pageTables.Allocator.NewPTEs()
-			pgdEntry.setPageTable(w.pageTables, pudEntries)
-		} else {
-			pudEntries = w.pageTables.Allocator.LookupPTEs(pgdEntry.Address())
-		}
-
-		clearPUDEntries := uint16(0)
-
-		for pudIndex := uint16((start & pudMask) >> pudShift); start < end && pudIndex < entriesPerPage; pudIndex++ {
-			var (
-				pudEntry   = &pudEntries[pudIndex]
-				pmdEntries *PTEs
-			)
-			if !pudEntry.Valid() {
-				if !w.visitor.requiresAlloc() {
-
-					clearPUDEntries++
-					start = unmapnext(start, pudSize)
-					continue
-				}
-
-				if start&(pudSize-1) == 0 && end-start >= pudSize {
-					pudEntry.SetSuper()
-					w.visitor.visit(uintptr(start), pudEntry, pudSize-1)
-					if pudEntry.Valid() {
-						start = unmapnext(start, pudSize)
-						continue
-					}
-				}
-
-				pmdEntries = w.pageTables.Allocator.NewPTEs()
-				pudEntry.setPageTable(w.pageTables, pmdEntries)
-
-			} else if pudEntry.IsSuper() {
-
-				if w.visitor.requiresSplit() && (start&(pudSize-1) != 0 || end < unmapnext(start, pudSize)) {
-
-					pmdEntries = w.pageTables.Allocator.NewPTEs()
-					for index := uint16(0); index < entriesPerPage; index++ {
-						pmdEntries[index].SetSuper()
-						pmdEntries[index].Set(
-							pudEntry.Address()+(pmdSize*uintptr(index)),
-							pudEntry.Opts())
-					}
-					pudEntry.setPageTable(w.pageTables, pmdEntries)
-				} else {
-
-					w.visitor.visit(uintptr(start), pudEntry, pudSize-1)
-
-					if !pudEntry.Valid() {
-						clearPUDEntries++
-					}
-
-					start = unmapnext(start, pudSize)
-					continue
-				}
-			} else {
-				pmdEntries = w.pageTables.Allocator.LookupPTEs(pudEntry.Address())
-			}
-
-			clearPMDEntries := uint16(0)
-
-			for pmdIndex := uint16((start & pmdMask) >> pmdShift); start < end && pmdIndex < entriesPerPage; pmdIndex++ {
-				var (
-					pmdEntry   = &pmdEntries[pmdIndex]
-					pteEntries *PTEs
-				)
-				if !pmdEntry.Valid() {
-					if !w.visitor.requiresAlloc() {
-
-						clearPMDEntries++
-						start = unmapnext(start, pmdSize)
-						continue
-					}
-
-					if start&(pmdSize-1) == 0 && end-start >= pmdSize {
-						pmdEntry.SetSuper()
-						w.visitor.visit(uintptr(start), pmdEntry, pmdSize-1)
-						if pmdEntry.Valid() {
-							start = unmapnext(start, pmdSize)
-							continue
-						}
-					}
-
-					pteEntries = w.pageTables.Allocator.NewPTEs()
-					pmdEntry.setPageTable(w.pageTables, pteEntries)
-
-				} else if pmdEntry.IsSuper() {
-
-					if w.visitor.requiresSplit() && (start&(pmdSize-1) != 0 || end < unmapnext(start, pmdSize)) {
-
-						pteEntries = w.pageTables.Allocator.NewPTEs()
-						for index := uint16(0); index < entriesPerPage; index++ {
-							pteEntries[index].Set(
-								pmdEntry.Address()+(pteSize*uintptr(index)),
-								pmdEntry.Opts())
-						}
-						pmdEntry.setPageTable(w.pageTables, pteEntries)
-					} else {
-
-						w.visitor.visit(uintptr(start), pmdEntry, pmdSize-1)
-
-						if !pmdEntry.Valid() {
-							clearPMDEntries++
-						}
-
-						start = unmapnext(start, pmdSize)
-						continue
-					}
-				} else {
-					pteEntries = w.pageTables.Allocator.LookupPTEs(pmdEntry.Address())
-				}
-
-				clearPTEEntries := uint16(0)
-
-				for pteIndex := uint16((start & pteMask) >> pteShift); start < end && pteIndex < entriesPerPage; pteIndex++ {
-					var (
-						pteEntry = &pteEntries[pteIndex]
-					)
-					if !pteEntry.Valid() && !w.visitor.requiresAlloc() {
-						clearPTEEntries++
-						start += pteSize
-						continue
-					}
-
-					w.visitor.visit(uintptr(start), pteEntry, pteSize-1)
-					if !pteEntry.Valid() {
-						if w.visitor.requiresAlloc() {
-							panic("PTE not set after iteration with requiresAlloc!")
-						}
-						clearPTEEntries++
-					}
-
-					start += pteSize
-					continue
-				}
-
-				if clearPTEEntries == entriesPerPage {
-					pmdEntry.Clear()
-					w.pageTables.Allocator.FreePTEs(pteEntries)
-					clearPMDEntries++
-				}
-			}
-
-			if clearPMDEntries == entriesPerPage {
-				pudEntry.Clear()
-				w.pageTables.Allocator.FreePTEs(pmdEntries)
-				clearPUDEntries++
-			}
-		}
-
-		if clearPUDEntries == entriesPerPage {
-			pgdEntry.Clear()
-			w.pageTables.Allocator.FreePTEs(pudEntries)
-		}
-	}
-}