On Sun, 2023-06-18 at 00:08 +0000, Mingwei Zhang wrote: > Add tdp_mmu_root_count into kvm_mmu_page description. tdp_mmu_root_count is > an atomic counter used only in TDP MMU. Its usage and meaning is slightly > different with root_counter in shadow MMU. Update the doc. > > Signed-off-by: Mingwei Zhang <mizhang@xxxxxxxxxx> > --- > Documentation/virt/kvm/x86/mmu.rst | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/Documentation/virt/kvm/x86/mmu.rst b/Documentation/virt/kvm/x86/mmu.rst > index 36bfe0fe02bb..3dce2426ad6d 100644 > --- a/Documentation/virt/kvm/x86/mmu.rst > +++ b/Documentation/virt/kvm/x86/mmu.rst > @@ -230,6 +230,12 @@ Shadow pages contain the following information: > A counter keeping track of how many hardware registers (guest cr3 or > pdptrs) are now pointing at the page. While this counter is nonzero, the > page cannot be destroyed. See role.invalid. > + tdp_mmu_root_count: > + An atomic reference counter in TDP MMU that allows for parallel ^ Please explicitly say "TDP MMU root page" ? > + accesses. Accessing the page requires lifting the counter value. The > + initial value is set as 2 indicating one reference from vCPU and one ^ to ? > + from TDP MMU itself. > > While this counter is nonzero, the page cannot be > + destroyed. > I guess this sentence is implied by "reference counter" mentioned in the first sentence. > Note this field is a union with root_count. >
