KVM: nVMX: Correct handling of exception injection

Similar to the previous patch, but concerning injection of exceptions rather
than external interrupts.

Signed-off-by: Nadav Har'El <nyh@il.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

1 files changed, 26 insertions, 0 deletions

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index ab218da8b956..9604af7675e8 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1585,6 +1585,25 @@ static void vmx_clear_hlt(struct kvm_vcpu *vcpu)
                 vmcs_write32(GUEST_ACTIVITY_STATE, GUEST_ACTIVITY_ACTIVE);
 }
 
+/*
+ * KVM wants to inject page-faults which it got to the guest. This function
+ * checks whether in a nested guest, we need to inject them to L1 or L2.
+ * This function assumes it is called with the exit reason in vmcs02 being
+ * a #PF exception (this is the only case in which KVM injects a #PF when L2
+ * is running).
+ */
+static int nested_pf_handled(struct kvm_vcpu *vcpu)
+{
+        struct vmcs12 *vmcs12 = get_vmcs12(vcpu);
+
+        /* TODO: also check PFEC_MATCH/MASK, not just EB.PF. */
+        if (!(vmcs12->exception_bitmap & PF_VECTOR))
+                return 0;
+
+        nested_vmx_vmexit(vcpu);
+        return 1;
+}
+
 static void vmx_queue_exception(struct kvm_vcpu *vcpu, unsigned nr,
                                 bool has_error_code, u32 error_code,
                                 bool reinject)
@@ -1592,6 +1611,10 @@ static void vmx_queue_exception(struct kvm_vcpu *vcpu, unsigned nr,
         struct vcpu_vmx *vmx = to_vmx(vcpu);
         u32 intr_info = nr | INTR_INFO_VALID_MASK;
 
+        if (nr == PF_VECTOR && is_guest_mode(vcpu) &&
+                nested_pf_handled(vcpu))
+                return;
+
         if (has_error_code) {
                 vmcs_write32(VM_ENTRY_EXCEPTION_ERROR_CODE, error_code);
                 intr_info |= INTR_INFO_DELIVER_CODE_MASK;
@@ -3820,6 +3843,9 @@ static void vmx_inject_nmi(struct kvm_vcpu *vcpu)
 {
         struct vcpu_vmx *vmx = to_vmx(vcpu);
 
+        if (is_guest_mode(vcpu))
+                return;
+
         if (!cpu_has_virtual_nmis()) {
                 /*
                  * Tracking the NMI-blocked state in software is built upon