On Mon, Jul 31, 2023, Mingwei Zhang wrote: > On Mon, Jun 26, 2023, Randy Dunlap wrote: > > Hi-- > > > > On 6/26/23 11:20, Mingwei Zhang wrote: > > > Update the field 'gfns' in kvm_mmu_page to 'shadowed_translation' to be > > > consistent with the code. Also update the corresponding 'gfns' in the > > > comments. The more detailed description of 'shadowed_translation' is > > > already inlined in the data structure definition, so no need to duplicate > > > the text but simply just update the names. > > > > > > Signed-off-by: Mingwei Zhang <mizhang@xxxxxxxxxx> > > > Reviewed-by: Kai Huang <kai.huang@xxxxxxxxx> > > > --- > > > Documentation/virt/kvm/x86/mmu.rst | 9 +++++---- > > > 1 file changed, 5 insertions(+), 4 deletions(-) > > > > > > diff --git a/Documentation/virt/kvm/x86/mmu.rst b/Documentation/virt/kvm/x86/mmu.rst > > > index 561efa8ec7d7..4c9044b4dc6c 100644 > > > --- a/Documentation/virt/kvm/x86/mmu.rst > > > +++ b/Documentation/virt/kvm/x86/mmu.rst > > > @@ -221,11 +221,12 @@ Shadow pages contain the following information: > > > at __pa(sp2->spt). sp2 will point back at sp1 through parent_pte. > > > The spt array forms a DAG structure with the shadow page as a node, and > > > guest pages as leaves. > > > - gfns: > > > - An array of 512 guest frame numbers, one for each present pte. Used to > > > - perform a reverse map from a pte to a gfn. When role.direct is set, any > > > + shadowed_translation: > > > + An array of 512 shadow translation entries, one for each present pte. Used > > > + to perform a reverse map from a pte to a gfn. When role.direct is set, any > > > element of this array can be calculated from the gfn field when used, in > > > - this case, the array of gfns is not allocated. See role.direct and gfn. > > > + this case, the array of shadowed_translation is not allocated. See > > > > I cannot parse the before version nor the after version of this sentence (new version): > > > > When role.direct is set, any > > element of this array can be calculated from the gfn field when used, in > > this case, the array of shadowed_translation is not allocated. > > > > > > Sorry for the late reply. Why is it not parsed? It just means that when > role.direct is set, do not use gfns. The gfn can be calculated from the > base address + offset. The base address here is the 'gfn' field in > kvm_mmu_page. It's a bit of a run-on sentence with confusing pronoun usage. How about this? When role.direct is set, the shadow_translation array is not allocated as the per-SPTE gfn is simply an offset from the base gfn, and KVM doesn't track access permissions for direct shadow pages.
