static int vcpu_mmio_gva_to_gpa(struct kvm_vcpu *vcpu, unsigned long gva,
				gpa_t *gpa, struct x86_exception *exception,
				bool write)
{
	u32 access = ((kvm_x86_ops->get_cpl(vcpu) == 3) ? PFERR_USER_MASK : 0)
		| (write ? PFERR_WRITE_MASK : 0);

	if (vcpu_match_mmio_gva(vcpu, gva)
	    && !permission_fault(vcpu, vcpu->arch.walk_mmu,
				 vcpu->arch.access, access)) {
		*gpa = vcpu->arch.mmio_gfn << PAGE_SHIFT |
					(gva & (PAGE_SIZE - 1));
		trace_vcpu_match_mmio(gva, *gpa, write, false);
		return 1;
	}

	*gpa = vcpu->arch.walk_mmu->gva_to_gpa(vcpu, gva, access, exception);

	if (*gpa == UNMAPPED_GVA)
		return -1;

	/* For APIC access vmexit */
	if ((*gpa & PAGE_MASK) == APIC_DEFAULT_PHYS_BASE)
		return 1;

	if (vcpu_match_mmio_gpa(vcpu, *gpa)) {
		trace_vcpu_match_mmio(gva, *gpa, write, true);
		return 1;
	}

	return 0;
}

The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.