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Reply-To: Mingwei Zhang <mizhang@google.com>
Date:   Mon, 26 Jun 2023 18:20:13 +0000
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Message-ID: <20230626182016.4127366-4-mizhang@google.com>
Subject: [PATCH v2 3/6] KVM: Documentation: Add the missing description for
 ptep in kvm_mmu_page
From:   Mingwei Zhang <mizhang@google.com>
To:     Sean Christopherson <seanjc@google.com>,
        Paolo Bonzini <pbonzini@redhat.com>
Cc:     kvm@vger.kernel.org, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org, Mingwei Zhang <mizhang@google.com>,
        Kai Huang <kai.huang@intel.com>,
        Jim Mattson <jmattson@google.com>,
        David Matlack <dmatlack@google.com>,
        Ben Gardon <bgardon@google.com>, Xu Yilun <yilun.xu@intel.com>,
        Zhi Wang <zhi.wang.linux@gmail.com>
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Add the missing description for 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@google.com>
---
 Documentation/virt/kvm/x86/mmu.rst | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Documentation/virt/kvm/x86/mmu.rst b/Documentation/virt/kvm/x86/mmu.rst
index 4c9044b4dc6c..5cd6cd5e8926 100644
--- a/Documentation/virt/kvm/x86/mmu.rst
+++ b/Documentation/virt/kvm/x86/mmu.rst
@@ -237,6 +237,11 @@ 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:
+    The reverse mapping for the pte pointing at this page's spt. This field is
+    used in replace of parent_ptes when TDP MMU is used. In TDP MMU, each
+    non-root shadow page will have one parent, while each root shadow page has
+    no parent. Note that this field is a union with parent_ptes.
   unsync:
     If true, then the translations in this page may not match the guest's
     translation.  This is equivalent to the state of the tlb when a pte is
-- 
2.41.0.162.gfafddb0af9-goog