On Wed, Aug 26, 2026 at 12:13:47AM +0800, Xiaoyao Li wrote: > On 8/20/2026 9:32 AM, Sean Christopherson wrote: > > And vice versa, a PUNCH_HOLE on a SHARED gmem (if userspace is > > using an INIT_SHARED gmem for the shared branch of a memslot) could > > invalidate the > > PRIVATE mappings (of a different gmem instance). > > I'm wondering now how this could happen. > > the requirement for PUNCH_HOLE on gmem to trigger mapping invalidation is > the gmem is bound with the memslot. But how can a memslot bound with two > gmem instances?
I think this is for when userspace uses an mmap'able guest_memfd instance to handle shared memory, and a 'normal' guest_memfd instance for private memory. Each instance is bound to the same memslot/GPA range, and KVM_SET_MEMORY_ATTRIBUTES handles switching between the 2. -Mike
