From 659b10d1a6a236765be8b6e6dc0d72eaa55253ee Mon Sep 17 00:00:00 2001 From: Adin Scannell Date: Fri, 1 Jun 2018 13:50:17 -0700 Subject: Move page tables lock into the address space. This is necessary to prevent races with invalidation. It is currently possible that page tables are garbage collected while paging caches refer to them. We must ensure that pages are held until caches can be invalidated. This is not achieved by this goal alone, but moving locking to outside the page tables themselves is a requisite. PiperOrigin-RevId: 198920784 Change-Id: I66fffecd49cb14aa2e676a84a68cabfc0c8b3e9a --- pkg/sentry/platform/ring0/pagetables/pagetables.go | 8 -------- 1 file changed, 8 deletions(-) (limited to 'pkg/sentry/platform/ring0') diff --git a/pkg/sentry/platform/ring0/pagetables/pagetables.go b/pkg/sentry/platform/ring0/pagetables/pagetables.go index 2df6792f7..2a83bbff2 100644 --- a/pkg/sentry/platform/ring0/pagetables/pagetables.go +++ b/pkg/sentry/platform/ring0/pagetables/pagetables.go @@ -16,8 +16,6 @@ package pagetables import ( - "sync" - "gvisor.googlesource.com/gvisor/pkg/sentry/usermem" ) @@ -39,8 +37,6 @@ type Node struct { // PageTables is a set of page tables. type PageTables struct { - mu sync.Mutex - // root is the pagetable root. root *Node @@ -122,7 +118,6 @@ func (p *PageTables) Map(addr usermem.Addr, length uintptr, opts MapOpts, physic return p.Unmap(addr, length) } prev := false - p.mu.Lock() end, ok := addr.AddLength(uint64(length)) if !ok { panic("pagetables.Map: overflow") @@ -139,7 +134,6 @@ func (p *PageTables) Map(addr usermem.Addr, length uintptr, opts MapOpts, physic } pte.Set(p, opts) }) - p.mu.Unlock() return prev } @@ -147,13 +141,11 @@ func (p *PageTables) Map(addr usermem.Addr, length uintptr, opts MapOpts, physic // // True is returned iff there was a previous mapping in the range. func (p *PageTables) Unmap(addr usermem.Addr, length uintptr) bool { - p.mu.Lock() count := 0 p.iterateRange(uintptr(addr), uintptr(addr)+length, false, func(s, e uintptr, pte *PTE, align uintptr) { pte.Clear() count++ }) - p.mu.Unlock() return count > 0 } -- cgit v1.2.3