Add the description for tdp_mmu_page into kvm_mmu_page description.
tdp_mmu_page is a field to differentiate shadow pages from TDP MMU and
non-TDP MMU.

Signed-off-by: Mingwei Zhang <mizhang@google.com>
Reviewed-by: Kai Huang <kai.huang@intel.com>
---
 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 16d5d6a1c174..82c5c6a6da2c 100644
--- a/Documentation/virt/kvm/x86/mmu.rst
+++ b/Documentation/virt/kvm/x86/mmu.rst
@@ -282,6 +282,10 @@ Shadow pages contain the following information:
     since the last time the page table was actually used; if emulation
     is triggered too frequently on this page, KVM will unmap the page
     to avoid emulation in the future.
+  tdp_mmu_page:
+    Is 1 if the shadow page is a TDP MMU page. This variable is used to
+    bifurcate the control flows for KVM when walking any data structure that may
+    contain pages from both TDP MMU and shadow MMU.
 
 Reverse map
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-- 
2.42.0.283.g2d96d420d3-goog