On Tue, Nov 30, 2021, Maciej S. Szmigiero wrote: > From: "Maciej S. Szmigiero" <maciej.szmigiero@xxxxxxxxxx> > > kvm_invalidate_memslot() calls kvm_arch_flush_shadow_memslot() on the > active, but KVM_MEMSLOT_INVALID slot. > Do it on the inactive (but valid) old slot instead since arch code really > should not get passed such invalid slot. One other thing that's worth noting in the changelog is that "old->arch" may have stale data. IMO that's perfectly ok, but it's definitely a quirk. Ideally KVM would disallow touching "arch" for an INVALID slot, but that would require another arch hook if kvm_prepare_memory_region() failed to refresh old->arch if necessary before restoring it. :-/ Paolo, thoughts on this goofy case? I don't love it, but I dislike having kvm_arch_flush_shadow_memslot(kvm, invalid_slot); in the final code even more. Reviewed-by: Sean Christopherson <seanjc@xxxxxxxxxx> > Suggested-by: Sean Christopherson <seanjc@xxxxxxxxxx> > Signed-off-by: Maciej S. Szmigiero <maciej.szmigiero@xxxxxxxxxx> > --- > virt/kvm/kvm_main.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index c57748ee41e8..086f18969bc3 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -1632,7 +1632,7 @@ static void kvm_invalidate_memslot(struct kvm *kvm, > * - gfn_to_hva (kvm_read_guest, gfn_to_pfn) > * - kvm_is_visible_gfn (mmu_check_root) > */ > - kvm_arch_flush_shadow_memslot(kvm, working_slot); > + kvm_arch_flush_shadow_memslot(kvm, old); > > /* Was released by kvm_swap_active_memslots, reacquire. */ > mutex_lock(&kvm->slots_arch_lock);
