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| author | Mingwei Zhang <mizhang@google.com> | 2023-09-12 21:45:52 +0300 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2023-09-27 23:29:32 +0300 |
| commit | c3204c406b6d4223022af26699bd3a5b71ba5fd8 (patch) | |
| tree | 27361bb3e5f71c534d8c61895451cbef086048cc /Documentation/virt/kvm/x86/mmu.rst | |
| parent | 6a713928ae1cb8aaa008b6ffb709fd9293614c89 (diff) | |
| download | linux-c3204c406b6d4223022af26699bd3a5b71ba5fd8.tar.xz | |
KVM: Documentation: Add the missing description for mmu_valid_gen into kvm_mmu_page
Add the description for mmu_valid_gen into kvm_mmu_page description.
mmu_valid_gen is used in shadow MMU for fast zapping. Update the doc to
reflect that.
Signed-off-by: Mingwei Zhang <mizhang@google.com>
Reviewed-by: Kai Huang <kai.huang@intel.com>
Link: https://lore.kernel.org/r/20230912184553.1887764-6-mizhang@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'Documentation/virt/kvm/x86/mmu.rst')
| -rw-r--r-- | Documentation/virt/kvm/x86/mmu.rst | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/Documentation/virt/kvm/x86/mmu.rst b/Documentation/virt/kvm/x86/mmu.rst index 55d72383f6d6..d04729c180da 100644 --- a/Documentation/virt/kvm/x86/mmu.rst +++ b/Documentation/virt/kvm/x86/mmu.rst @@ -208,6 +208,16 @@ Shadow pages contain the following information: The page is not backed by a guest page table, but its first entry points to one. This is set if NPT uses 5-level page tables (host CR4.LA57=1) and is shadowing L1's 4-level NPT (L1 CR4.LA57=0). + mmu_valid_gen: + The MMU generation of this page, used to fast zap of all MMU pages within a + VM without blocking vCPUs too long. Specifically, KVM updates the per-VM + valid MMU generation which causes the mismatch of mmu_valid_gen for each mmu + page. This makes all existing MMU pages obsolete. Obsolete pages can't be + used. Therefore, vCPUs must load a new, valid root before re-entering the + guest. The MMU generation is only ever '0' or '1'. Note, the TDP MMU doesn't + use this field as non-root TDP MMU pages are reachable only from their + owning root. Thus it suffices for TDP MMU to use role.invalid in root pages + to invalidate all MMU pages. gfn: Either the guest page table containing the translations shadowed by this page, or the base page frame for linear translations. See role.direct. |