KVM: x86: make double/triple fault promotion generic to all exceptions

Move Double-Fault generation logic out of page fault
exception generating function to cover more generic case.

Signed-off-by: Eddie Dong <eddie.dong@intel.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index a1e1bc9..8d860e0 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -257,12 +257,68 @@ void kvm_set_apic_base(struct kvm_vcpu *vcpu, u64 data)
 }
 EXPORT_SYMBOL_GPL(kvm_set_apic_base);
 
+#define EXCPT_BENIGN           0
+#define EXCPT_CONTRIBUTORY     1
+#define EXCPT_PF               2
+
+static int exception_class(int vector)
+{
+       switch (vector) {
+       case PF_VECTOR:
+               return EXCPT_PF;
+       case DE_VECTOR:
+       case TS_VECTOR:
+       case NP_VECTOR:
+       case SS_VECTOR:
+       case GP_VECTOR:
+               return EXCPT_CONTRIBUTORY;
+       default:
+               break;
+       }
+       return EXCPT_BENIGN;
+}
+
+static void kvm_multiple_exception(struct kvm_vcpu *vcpu,
+               unsigned nr, bool has_error, u32 error_code)
+{
+       u32 prev_nr;
+       int class1, class2;
+
+       if (!vcpu->arch.exception.pending) {
+       queue:
+               vcpu->arch.exception.pending = true;
+               vcpu->arch.exception.has_error_code = has_error;
+               vcpu->arch.exception.nr = nr;
+               vcpu->arch.exception.error_code = error_code;
+               return;
+       }
+
+       /* to check exception */
+       prev_nr = vcpu->arch.exception.nr;
+       if (prev_nr == DF_VECTOR) {
+               /* triple fault -> shutdown */
+               set_bit(KVM_REQ_TRIPLE_FAULT, &vcpu->requests);
+               return;
+       }
+       class1 = exception_class(prev_nr);
+       class2 = exception_class(nr);
+       if ((class1 == EXCPT_CONTRIBUTORY && class2 == EXCPT_CONTRIBUTORY)
+               || (class1 == EXCPT_PF && class2 != EXCPT_BENIGN)) {
+               /* generate double fault per SDM Table 5-5 */
+               vcpu->arch.exception.pending = true;
+               vcpu->arch.exception.has_error_code = true;
+               vcpu->arch.exception.nr = DF_VECTOR;
+               vcpu->arch.exception.error_code = 0;
+       } else
+               /* replace previous exception with a new one in a hope
+                  that instruction re-execution will regenerate lost
+                  exception */
+               goto queue;
+}
+
 void kvm_queue_exception(struct kvm_vcpu *vcpu, unsigned nr)
 {
-       WARN_ON(vcpu->arch.exception.pending);
-       vcpu->arch.exception.pending = true;
-       vcpu->arch.exception.has_error_code = false;
-       vcpu->arch.exception.nr = nr;
+       kvm_multiple_exception(vcpu, nr, false, 0);
 }
 EXPORT_SYMBOL_GPL(kvm_queue_exception);
 
@@ -270,25 +326,6 @@ void kvm_inject_page_fault(struct kvm_vcpu *vcpu, unsigned long addr,
                           u32 error_code)
 {
        ++vcpu->stat.pf_guest;
-
-       if (vcpu->arch.exception.pending) {
-               switch(vcpu->arch.exception.nr) {
-               case DF_VECTOR:
-                       /* triple fault -> shutdown */
-                       set_bit(KVM_REQ_TRIPLE_FAULT, &vcpu->requests);
-                       return;
-               case PF_VECTOR:
-                       vcpu->arch.exception.nr = DF_VECTOR;
-                       vcpu->arch.exception.error_code = 0;
-                       return;
-               default:
-                       /* replace previous exception with a new one in a hope
-                          that instruction re-execution will regenerate lost
-                          exception */
-                       vcpu->arch.exception.pending = false;
-                       break;
-               }
-       }
        vcpu->arch.cr2 = addr;
        kvm_queue_exception_e(vcpu, PF_VECTOR, error_code);
 }
@@ -301,11 +338,7 @@ EXPORT_SYMBOL_GPL(kvm_inject_nmi);
 
 void kvm_queue_exception_e(struct kvm_vcpu *vcpu, unsigned nr, u32 error_code)
 {
-       WARN_ON(vcpu->arch.exception.pending);
-       vcpu->arch.exception.pending = true;
-       vcpu->arch.exception.has_error_code = true;
-       vcpu->arch.exception.nr = nr;
-       vcpu->arch.exception.error_code = error_code;
+       kvm_multiple_exception(vcpu, nr, true, error_code);
 }
 EXPORT_SYMBOL_GPL(kvm_queue_exception_e);