On Fri, Dec 24, 2021 at 12:13:51PM +0800, Chao Peng wrote: > On Thu, Dec 23, 2021 at 06:06:19PM +0000, Sean Christopherson wrote: > > On Thu, Dec 23, 2021, Chao Peng wrote: > > > This new function establishes the mapping in KVM page tables for a > > > given gfn range. It can be used in the memory fallocate callback for > > > memfd based memory to establish the mapping for KVM secondary MMU when > > > the pages are allocated in the memory backend. > > > > NAK, under no circumstance should KVM install SPTEs in response to > > allocating > > memory in a file. The correct thing to do is to invalidate the gfn range > > associated with the newly mapped range, i.e. wipe out any shared SPTEs > > associated > > with the memslot. > > Right, thanks.
BTW, I think the current fallocate() callback is just useless as long as we don't want to install KVM SPTEs in response to allocating memory in a file. The invalidation of the shared SPTEs should be notified through mmu_notifier of the shared memory backend, not memfd_notifier of the private memory backend. Thanks, Chao
