@@ -104,6 +104,9 @@ void kvm_mmu_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new,
static inline int kvm_mmu_reload(struct kvm_vcpu *vcpu)
{
+ if (kvm_check_request(KVM_REQ_MMU_FREE_OBSOLETE_ROOTS, vcpu))
+ kvm_mmu_free_obsolete_roots(vcpu);
+
/*
* Checking root.hpa is sufficient even when KVM has mirror root.
* We can have either:
@@ -5802,6 +5802,7 @@ void kvm_mmu_free_obsolete_roots(struct kvm_vcpu *vcpu)
__kvm_mmu_free_obsolete_roots(vcpu->kvm, &vcpu->arch.root_mmu);
__kvm_mmu_free_obsolete_roots(vcpu->kvm, &vcpu->arch.guest_mmu);
}
+EXPORT_SYMBOL_GPL(kvm_mmu_free_obsolete_roots);
static u64 mmu_pte_write_fetch_gpte(struct kvm_vcpu *vcpu, gpa_t *gpa,
int *bytes)
Check request KVM_REQ_MMU_FREE_OBSOLETE_ROOTS to free obsolete roots in kvm_mmu_reload() to prevent kvm_mmu_reload() from seeing a stale obsolete root. Since kvm_mmu_reload() can be called outside the vcpu_enter_guest() path (e.g., kvm_arch_vcpu_pre_fault_memory()), it may be invoked after a root has been marked obsolete and before vcpu_enter_guest() is invoked to process KVM_REQ_MMU_FREE_OBSOLETE_ROOTS and set root.hpa to invalid. This causes kvm_mmu_reload() to fail to load a new root, which can lead to kvm_arch_vcpu_pre_fault_memory() being stuck in the while loop in kvm_tdp_map_page() since RET_PF_RETRY is always returned due to is_page_fault_stale(). Keep the existing check of KVM_REQ_MMU_FREE_OBSOLETE_ROOTS in vcpu_enter_guest() since the cost of kvm_check_request() is negligible, especially a check that's guarded by kvm_request_pending(). Export symbol of kvm_mmu_free_obsolete_roots() as kvm_mmu_reload() is inline and may be called outside of kvm.ko. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Yan Zhao <yan.y.zhao@intel.com> --- arch/x86/kvm/mmu.h | 3 +++ arch/x86/kvm/mmu/mmu.c | 1 + 2 files changed, 4 insertions(+)