KVM: async_pf: Fix #DF due to inject "Page not Present" and "Page Ready" exceptions...
[sfrench/cifs-2.6.git] / arch / x86 / kvm / x86.c
index bfda79fb102c459c05393311fd81633cd8ba45d6..cd17b7d9a1076c1d28904bc4cd1ea06af5e0f2c0 100644 (file)
@@ -8631,6 +8631,13 @@ static int apf_put_user(struct kvm_vcpu *vcpu, u32 val)
                                      sizeof(val));
 }
 
+static int apf_get_user(struct kvm_vcpu *vcpu, u32 *val)
+{
+
+       return kvm_read_guest_cached(vcpu->kvm, &vcpu->arch.apf.data, val,
+                                     sizeof(u32));
+}
+
 void kvm_arch_async_page_not_present(struct kvm_vcpu *vcpu,
                                     struct kvm_async_pf *work)
 {
@@ -8658,6 +8665,7 @@ void kvm_arch_async_page_present(struct kvm_vcpu *vcpu,
                                 struct kvm_async_pf *work)
 {
        struct x86_exception fault;
+       u32 val;
 
        if (work->wakeup_all)
                work->arch.token = ~0; /* broadcast wakeup */
@@ -8665,15 +8673,26 @@ void kvm_arch_async_page_present(struct kvm_vcpu *vcpu,
                kvm_del_async_pf_gfn(vcpu, work->arch.gfn);
        trace_kvm_async_pf_ready(work->arch.token, work->gva);
 
-       if ((vcpu->arch.apf.msr_val & KVM_ASYNC_PF_ENABLED) &&
-           !apf_put_user(vcpu, KVM_PV_REASON_PAGE_READY)) {
-               fault.vector = PF_VECTOR;
-               fault.error_code_valid = true;
-               fault.error_code = 0;
-               fault.nested_page_fault = false;
-               fault.address = work->arch.token;
-               fault.async_page_fault = true;
-               kvm_inject_page_fault(vcpu, &fault);
+       if (vcpu->arch.apf.msr_val & KVM_ASYNC_PF_ENABLED &&
+           !apf_get_user(vcpu, &val)) {
+               if (val == KVM_PV_REASON_PAGE_NOT_PRESENT &&
+                   vcpu->arch.exception.pending &&
+                   vcpu->arch.exception.nr == PF_VECTOR &&
+                   !apf_put_user(vcpu, 0)) {
+                       vcpu->arch.exception.injected = false;
+                       vcpu->arch.exception.pending = false;
+                       vcpu->arch.exception.nr = 0;
+                       vcpu->arch.exception.has_error_code = false;
+                       vcpu->arch.exception.error_code = 0;
+               } else if (!apf_put_user(vcpu, KVM_PV_REASON_PAGE_READY)) {
+                       fault.vector = PF_VECTOR;
+                       fault.error_code_valid = true;
+                       fault.error_code = 0;
+                       fault.nested_page_fault = false;
+                       fault.address = work->arch.token;
+                       fault.async_page_fault = true;
+                       kvm_inject_page_fault(vcpu, &fault);
+               }
        }
        vcpu->arch.apf.halted = false;
        vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;