diff options
| author | Sean Christopherson <seanjc@google.com> | 2021-12-15 04:15:55 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-04-08 15:24:03 +0300 |
| commit | 31a70b170e06e030bc4bf9542cb841834513b943 (patch) | |
| tree | 0dace551a69309b16730821c978d7fcd6dabf9a0 /arch | |
| parent | 48306afcac2a027163c6a8d10bd7a1d9d10efe37 (diff) | |
| download | linux-31a70b170e06e030bc4bf9542cb841834513b943.tar.xz | |
KVM: x86/mmu: Move "invalid" check out of kvm_tdp_mmu_get_root()
commit 04dc4e6ce274fa729feda32aa957b27388a3870c upstream.
Move the check for an invalid root out of kvm_tdp_mmu_get_root() and into
the one place it actually matters, tdp_mmu_next_root(), as the other user
already has an implicit validity check. A future bug fix will need to
get references to invalid roots to honor mmu_notifier requests; there's
no point in forcing what will be a common path to open code getting a
reference to a root.
No functional change intended.
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211215011557.399940-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/mmu/tdp_mmu.c | 12 | ||||
| -rw-r--r-- | arch/x86/kvm/mmu/tdp_mmu.h | 3 |
2 files changed, 10 insertions, 5 deletions
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index d479b2b12125..38f698e3f926 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -121,9 +121,14 @@ static struct kvm_mmu_page *tdp_mmu_next_root(struct kvm *kvm, next_root = list_first_or_null_rcu(&kvm->arch.tdp_mmu_roots, typeof(*next_root), link); - while (next_root && !kvm_tdp_mmu_get_root(kvm, next_root)) + while (next_root) { + if (!next_root->role.invalid && + kvm_tdp_mmu_get_root(kvm, next_root)) + break; + next_root = list_next_or_null_rcu(&kvm->arch.tdp_mmu_roots, &next_root->link, typeof(*next_root), link); + } rcu_read_unlock(); @@ -199,7 +204,10 @@ hpa_t kvm_tdp_mmu_get_vcpu_root_hpa(struct kvm_vcpu *vcpu) role = page_role_for_level(vcpu, vcpu->arch.mmu->shadow_root_level); - /* Check for an existing root before allocating a new one. */ + /* + * Check for an existing root before allocating a new one. Note, the + * role check prevents consuming an invalid root. + */ for_each_tdp_mmu_root(kvm, root, kvm_mmu_role_as_id(role)) { if (root->role.word == role.word && kvm_tdp_mmu_get_root(kvm, root)) diff --git a/arch/x86/kvm/mmu/tdp_mmu.h b/arch/x86/kvm/mmu/tdp_mmu.h index ba3681cd38ab..39468b637d2e 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.h +++ b/arch/x86/kvm/mmu/tdp_mmu.h @@ -10,9 +10,6 @@ hpa_t kvm_tdp_mmu_get_vcpu_root_hpa(struct kvm_vcpu *vcpu); __must_check static inline bool kvm_tdp_mmu_get_root(struct kvm *kvm, struct kvm_mmu_page *root) { - if (root->role.invalid) - return false; - return refcount_inc_not_zero(&root->tdp_mmu_root_count); } |