On Thu, 2025-04-24 at 11:08 +0800, Yan Zhao wrote:
> +static int kvm_gmem_invalidate_begin(struct kvm_gmem *gmem, pgoff_t start,
> + pgoff_t end, bool need_split)
> {
> bool flush = false, found_memslot = false;
> struct kvm_memory_slot *slot;
> struct kvm *kvm = gmem->kvm;
> unsigned long index;
> + int ret = 0;
>
> xa_for_each_range(&gmem->bindings, index, slot, start, end - 1) {
> pgoff_t pgoff = slot->gmem.pgoff;
> @@ -319,14 +320,23 @@ static void kvm_gmem_invalidate_begin(struct kvm_gmem *gmem, pgoff_t start,
> kvm_mmu_invalidate_begin(kvm);
> }
>
> + if (need_split) {
> + ret = kvm_split_boundary_leafs(kvm, &gfn_range);
What is the effect for other guestmemfd users? SEV doesn't need this, right? Oh
I see, down in tdp_mmu_split_boundary_leafs() it bails on non-mirror roots. I
don't like the naming then. It sounds deterministic, but it's really only
necessary splits for certain VM types.
I guess it all depends on how well teaching kvm_mmu_unmap_gfn_range() to fail
goes. But otherwise, we should call it like kvm_prepare_zap_range() or
something. And have it make it clearly do nothing for non-TDX high up where it's
easy to see.
> + if (ret < 0)
> + goto out;
> +
> + flush |= ret;
> + }
> flush |= kvm_mmu_unmap_gfn_range(kvm, &gfn_range);
> }
>
> +out:
> if (flush)
> kvm_flush_remote_tlbs(kvm);
>
> if (found_memslot)
> KVM_MMU_UNLOCK(kvm);
> +
