diff options
| author | Vipin Sharma <vipinsh@google.com> | 2023-03-22 01:00:10 +0300 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2023-04-04 22:37:30 +0300 |
| commit | 5982a5392663b30f57ee90b0372c19a7e9cb655a (patch) | |
| tree | a01ed7ecaf46c83da77839f27a75ecab34066b2a /arch/x86/kvm/mmu | |
| parent | 41e07665f1a683064f4c69b0d652dff1baf5d689 (diff) | |
| download | linux-5982a5392663b30f57ee90b0372c19a7e9cb655a.tar.xz | |
KVM: x86/mmu: Use kvm_ad_enabled() to determine if TDP MMU SPTEs need wrprot
Use the constant-after-module-load kvm_ad_enabled() to check if SPTEs in
the TDP MMU need to be write-protected when clearing accessed/dirty status
instead of manually checking every SPTE. The per-SPTE A/D enabling is
specific to nested EPT MMUs, i.e. when KVM is using EPT A/D bits but L1 is
not, and so cannot happen in the TDP MMU (which is non-nested only).
Keep the original code as sanity checks buried under MMU_WARN_ON().
MMU_WARN_ON() is more or less useless at the moment, but there are plans
to change that.
Link: https://lore.kernel.org/all/Yz4Qi7cn7TWTWQjj@google.com
Signed-off-by: Vipin Sharma <vipinsh@google.com>
[sean: split to separate patch, apply to dirty path, write changelog]
Link: https://lore.kernel.org/r/20230321220021.2119033-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'arch/x86/kvm/mmu')
| -rw-r--r-- | arch/x86/kvm/mmu/tdp_mmu.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index 7c25dbf32ecc..5a5642650c3e 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -1621,7 +1621,10 @@ retry: if (!is_shadow_present_pte(iter.old_spte)) continue; - if (spte_ad_need_write_protect(iter.old_spte)) { + MMU_WARN_ON(kvm_ad_enabled() && + spte_ad_need_write_protect(iter.old_spte)); + + if (!kvm_ad_enabled()) { if (is_writable_pte(iter.old_spte)) new_spte = iter.old_spte & ~PT_WRITABLE_MASK; else @@ -1685,13 +1688,16 @@ static void clear_dirty_pt_masked(struct kvm *kvm, struct kvm_mmu_page *root, if (!mask) break; + MMU_WARN_ON(kvm_ad_enabled() && + spte_ad_need_write_protect(iter.old_spte)); + if (iter.level > PG_LEVEL_4K || !(mask & (1UL << (iter.gfn - gfn)))) continue; mask &= ~(1UL << (iter.gfn - gfn)); - if (wrprot || spte_ad_need_write_protect(iter.old_spte)) { + if (wrprot || !kvm_ad_enabled()) { if (is_writable_pte(iter.old_spte)) new_spte = iter.old_spte & ~PT_WRITABLE_MASK; else |