On Sun, 2023-06-18 at 00:08 +0000, Mingwei Zhang wrote: > Add the missing ptep in kvm_mmu_page description. ptep is used when TDP MMU > is enabled and it shares the storage with parent_ptes. Update the doc to > help readers to get up-to-date info. > > Signed-off-by: Mingwei Zhang <mizhang@xxxxxxxxxx> > --- > Documentation/virt/kvm/x86/mmu.rst | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/Documentation/virt/kvm/x86/mmu.rst b/Documentation/virt/kvm/x86/mmu.rst > index 149dd3cba48f..36bfe0fe02bb 100644 > --- a/Documentation/virt/kvm/x86/mmu.rst > +++ b/Documentation/virt/kvm/x86/mmu.rst > @@ -236,6 +236,10 @@ Shadow pages contain the following information: > parent_ptes points at this single spte, otherwise, there exists multiple > sptes pointing at this page and (parent_ptes & ~0x1) points at a data > structure with a list of parent sptes. > + ptep: > + Pointer to the parent spte when TDP MMU is enabled. > IMHO "parent spte" alone _may_ be confusing. I think it's better to explicitly mention "pointing to this page" similar to the "parent_ptes" above. Also, I think "when TDP MMU is enabled" isn't strictly true, depending on what does "when TDP MMU is enabled mean". E.g., when tdp_mmu_enabled module parameter is true, we can still have a nested EPT shadow page from L2 which won't use this either IIUC. > In TDP MMU, each > + shadow page will have at most one parent. Note that this field is a > + union with parent_ptes. Also, perhaps "have at most one parent" can be more precise: only root page has no parent, while other non-root pages always have one parent SPTE pointing to each of them.
