diff options
Diffstat (limited to 'pkg/sentry/mm/mm.go')
| -rw-r--r-- | pkg/sentry/mm/mm.go | 27 |
1 files changed, 19 insertions, 8 deletions
diff --git a/pkg/sentry/mm/mm.go b/pkg/sentry/mm/mm.go index 6ed838d64..a3417a46e 100644 --- a/pkg/sentry/mm/mm.go +++ b/pkg/sentry/mm/mm.go @@ -71,9 +71,6 @@ type MemoryManager struct { // ownership is shared by one or more pmas instead of being owned by a // memmap.Mappable). // - // NOTE: This should be replaced using refcounts on - // platform.File. - // // privateRefs is immutable. privateRefs *privateRefs @@ -374,13 +371,27 @@ type pma struct { file platform.File `state:"nosave"` // off is the offset into file at which this pma begins. + // + // Note that pmas do *not* hold references on offsets in file! If private + // is true, MemoryManager.privateRefs holds the reference instead. If + // private is false, the corresponding memmap.Mappable holds the reference + // instead (per memmap.Mappable.Translate requirement). off uint64 - // vmaEffectivePerms and vmaMaxPerms are duplicated from the - // corresponding vma so that the IO implementation can avoid iterating - // mm.vmas when pmas already exist. - vmaEffectivePerms usermem.AccessType - vmaMaxPerms usermem.AccessType + // translatePerms is the permissions returned by memmap.Mappable.Translate. + // If private is true, translatePerms is usermem.AnyAccess. + translatePerms usermem.AccessType + + // effectivePerms is the permissions allowed for non-ignorePermissions + // accesses. maxPerms is the permissions allowed for ignorePermissions + // accesses. These are vma.effectivePerms and vma.maxPerms respectively, + // masked by pma.translatePerms and with Write disallowed if pma.needCOW is + // true. + // + // These are stored in the pma so that the IO implementation can avoid + // iterating mm.vmas when pmas already exist. + effectivePerms usermem.AccessType + maxPerms usermem.AccessType // needCOW is true if writes to the mapping must be propagated to a copy. needCOW bool |