@@ -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();
@@ -200,7 +205,10 @@ 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))
@@ -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);
}
Move the check for an invalid root out 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> --- arch/x86/kvm/mmu/tdp_mmu.c | 12 ++++++++++-- arch/x86/kvm/mmu/tdp_mmu.h | 3 --- 2 files changed, 10 insertions(+), 5 deletions(-)