diff options
| -rw-r--r-- | pkg/sentry/platform/kvm/address_space.go | 3 | ||||
| -rw-r--r-- | pkg/sentry/platform/kvm/allocator.go | 7 | ||||
| -rw-r--r-- | pkg/sentry/platform/ring0/pagetables/allocator.go | 19 |
3 files changed, 26 insertions, 3 deletions
diff --git a/pkg/sentry/platform/kvm/address_space.go b/pkg/sentry/platform/kvm/address_space.go index fbd11ed71..463617170 100644 --- a/pkg/sentry/platform/kvm/address_space.go +++ b/pkg/sentry/platform/kvm/address_space.go @@ -273,6 +273,9 @@ func (as *addressSpace) Unmap(addr usermem.Addr, length uint64) { Start: addr, End: addr + usermem.Addr(length), }) + + // Recycle any freed intermediate pages. + as.pageTables.Allocator.Recycle() } } diff --git a/pkg/sentry/platform/kvm/allocator.go b/pkg/sentry/platform/kvm/allocator.go index 80066bfc5..f5cebd5b3 100644 --- a/pkg/sentry/platform/kvm/allocator.go +++ b/pkg/sentry/platform/kvm/allocator.go @@ -67,3 +67,10 @@ func (a allocator) LookupPTEs(physical uintptr) *pagetables.PTEs { func (a allocator) FreePTEs(ptes *pagetables.PTEs) { a.base.FreePTEs(ptes) } + +// Recycle implements pagetables.Allocator.Recycle. +// +//go:nosplit +func (a allocator) Recycle() { + a.base.Recycle() +} diff --git a/pkg/sentry/platform/ring0/pagetables/allocator.go b/pkg/sentry/platform/ring0/pagetables/allocator.go index 1499623fb..049fd0247 100644 --- a/pkg/sentry/platform/ring0/pagetables/allocator.go +++ b/pkg/sentry/platform/ring0/pagetables/allocator.go @@ -27,8 +27,12 @@ type Allocator interface { // LookupPTEs looks up PTEs by physical address. LookupPTEs(physical uintptr) *PTEs - // FreePTEs frees a set of PTEs. + // FreePTEs marks a set of PTEs a freed, although they may not be available + // for use again until Recycle is called, below. FreePTEs(ptes *PTEs) + + // Recycle makes freed PTEs available for use again. + Recycle() } // RuntimeAllocator is a trivial allocator. @@ -42,6 +46,9 @@ type RuntimeAllocator struct { // pool is the set of free-to-use PTEs. pool []*PTEs + + // freed is the set of recently-freed PTEs. + freed []*PTEs } // NewRuntimeAllocator returns an allocator that uses runtime allocation. @@ -51,8 +58,15 @@ func NewRuntimeAllocator() *RuntimeAllocator { } } +// Recycle returns freed pages to the pool. +func (r *RuntimeAllocator) Recycle() { + r.pool = append(r.pool, r.freed...) + r.freed = r.freed[:0] +} + // Drain empties the pool. func (r *RuntimeAllocator) Drain() { + r.Recycle() for i, ptes := range r.pool { // Zap the entry in the underlying array to ensure that it can // be properly garbage collected. @@ -104,6 +118,5 @@ func (r *RuntimeAllocator) LookupPTEs(physical uintptr) *PTEs { // //go:nosplit func (r *RuntimeAllocator) FreePTEs(ptes *PTEs) { - // Add to the pool. - r.pool = append(r.pool, ptes) + r.freed = append(r.freed, ptes) } |