| Message ID | 20230618000856.1714902-5-mizhang@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: Documentation: Update document description for kvm_mmu_page and kvm_mmu_page_role | expand |
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@google.com> > --- > 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. >
On Thu, Jun 22, 2023, Huang, Kai wrote: > 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@google.com> > > --- > > 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. > Will make the changes in next version. -Mingwei
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 + accesses. Accessing the page requires lifting the counter value. The + initial value is set as 2 indicating one reference from vCPU and one + from TDP MMU itself. While this counter is nonzero, the page cannot be + destroyed. Note this field is a union with root_count. parent_ptes: The reverse mapping for the pte/ptes pointing at this page's spt. If parent_ptes bit 0 is zero, only one spte points at this page and
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@google.com> --- Documentation/virt/kvm/x86/mmu.rst | 6 ++++++ 1 file changed, 6 insertions(+)