diff options
| author | Sean Christopherson <seanjc@google.com> | 2022-02-26 03:15:41 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-03-08 18:59:09 +0300 |
| commit | 58298b068137f419de8bc839d54ceacaec788870 (patch) | |
| tree | eb453b5dafdba942b205b5df8b8fce07ee8fdb37 | |
| parent | efd995dae5eba57c5d28d6886a85298b390a4f07 (diff) | |
| download | linux-58298b068137f419de8bc839d54ceacaec788870.tar.xz | |
KVM: x86/mmu: Check for a REMOVED leaf SPTE before making the SPTE
Explicitly check for a REMOVED leaf SPTE prior to attempting to map
the final SPTE when handling a TDP MMU fault. Functionally, this is a
nop as tdp_mmu_set_spte_atomic() will eventually detect the frozen SPTE.
Pre-checking for a REMOVED SPTE is a minor optmization, but the real goal
is to allow tdp_mmu_set_spte_atomic() to have an invariant that the "old"
SPTE is never a REMOVED SPTE.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Ben Gardon <bgardon@google.com>
Message-Id: <20220226001546.360188-24-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| -rw-r--r-- | arch/x86/kvm/mmu/tdp_mmu.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index 3751a33ee258..cd6ceca5f2ba 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -1193,7 +1193,11 @@ int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault) } } - if (iter.level != fault->goal_level) { + /* + * Force the guest to retry the access if the upper level SPTEs aren't + * in place, or if the target leaf SPTE is frozen by another CPU. + */ + if (iter.level != fault->goal_level || is_removed_spte(iter.old_spte)) { rcu_read_unlock(); return RET_PF_RETRY; } |