On Fri, Mar 17, 2023, Yan Zhao wrote: > On Fri, Mar 10, 2023 at 04:22:47PM -0800, Sean Christopherson wrote: > > From: Yan Zhao <yan.y.zhao@xxxxxxxxx> > > > > Add a new page-track hook, track_remove_region(), that is called when a > > memslot DELETE operation is about to be committed. The "remove" hook > > will be used by KVMGT and will effectively replace the existing > > track_flush_slot() altogether now that KVM itself doesn't rely on the > > "flush" hook either. > > > > The "flush" hook is flawed as it's invoked before the memslot operation > > is guaranteed to succeed, i.e. KVM might ultimately keep the existing > > memslot without notifying external page track users, a.k.a. KVMGT. In > > practice, this can't currently happen on x86, but there are no guarantees > > that won't change in the future, not to mention that "flush" does a very > > poor job of describing what is happening. > > > > Pass in the gfn+nr_pages instead of the slot itself so external users, > > i.e. KVMGT, don't need to exposed to KVM internals (memslots). This will > > help set the stage for additional cleanups to the page-track APIs. > > > > Cc: Zhenyu Wang <zhenyuw@xxxxxxxxxxxxxxx> > > Signed-off-by: Yan Zhao <yan.y.zhao@xxxxxxxxx> > > Co-developed-by: Sean Christopherson <seanjc@xxxxxxxxxx> > > Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx> > ... > > > +void kvm_page_track_delete_slot(struct kvm *kvm, struct kvm_memory_slot *slot) > > +{ > > + struct kvm_page_track_notifier_head *head; > > + struct kvm_page_track_notifier_node *n; > > + int idx; > > + > > + head = &kvm->arch.track_notifier_head; > > + > > + if (hlist_empty(&head->track_notifier_list)) > > + return; > > + > > + idx = srcu_read_lock(&head->track_srcu); > > + hlist_for_each_entry_srcu(n, &head->track_notifier_list, node, > > + srcu_read_lock_held(&head->track_srcu)) > Sorry, not sure why the alignment here is not right. > Patchwork just sent me a mail to complain about it. > Would you mind helping fix it in the next version? Ah, it's off by two spaces, should be hlist_for_each_entry_srcu(n, &head->track_notifier_list, node, srcu_read_lock_held(&head->track_srcu)) I'll get it fixed in the next version.