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| author | Mingwei Zhang <mizhang@google.com> | 2023-09-12 18:45:51 +0000 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2023-09-27 13:29:32 -0700 |
| commit | 6a713928ae1cb8aaa008b6ffb709fd9293614c89 (patch) | |
| tree | 9ff25a32fcbf4579b1ce58725a4b4133ce1c6488 /Documentation/virt | |
| parent | b40a2455e9ebdf32417e979f043c2830dd3fb3bb (diff) | |
| download | linux-6a713928ae1cb8aaa008b6ffb709fd9293614c89.tar.gz | |
KVM: Documentation: Add the missing description for tdp_mmu_root_count into kvm_mmu_page
Add the description of tdp_mmu_root_count into kvm_mmu_page description and
combine it with the description of root_count. tdp_mmu_root_count is an
atomic counter used only in TDP MMU. Update the doc.
Signed-off-by: Mingwei Zhang <mizhang@google.com>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/r/20230912184553.1887764-5-mizhang@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'Documentation/virt')
| -rw-r--r-- | Documentation/virt/kvm/x86/mmu.rst | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/Documentation/virt/kvm/x86/mmu.rst b/Documentation/virt/kvm/x86/mmu.rst index d5b08b4e8ff13f..55d72383f6d6fa 100644 --- a/Documentation/virt/kvm/x86/mmu.rst +++ b/Documentation/virt/kvm/x86/mmu.rst @@ -229,10 +229,13 @@ Shadow pages contain the following information: can be calculated from the gfn field when used. In addition, when role.direct is set, KVM does not track access permission for each of the gfn. See role.direct and gfn. - root_count: - 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. + root_count / tdp_mmu_root_count: + root_count is a reference counter for root shadow pages in Shadow MMU. + vCPUs elevate the refcount when getting a shadow page that will be used as + a root page, i.e. page that will be loaded into hardware directly (CR3, + PDPTRs, nCR3 EPTP). Root pages cannot be destroyed while their refcount is + non-zero. See role.invalid. tdp_mmu_root_count is similar but exclusively + used in TDP MMU as an atomic refcount. 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 |