KVM: x86: reset MMU on KVM_SET_VCPU_EVENTS

Otherwise, mismatch between the smm bit in hflags and the MMU role
can cause a NULL pointer dereference.

Cc: stable@vger.kernel.org
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 445c51b6cf6dc702a0da9710ee5b6eb4b996ec34..0b387d61c10300e92a8be5c4c731d80b29a16167 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3070,6 +3070,8 @@ static void kvm_vcpu_ioctl_x86_get_vcpu_events(struct kvm_vcpu *vcpu,
        memset(&events->reserved, 0, sizeof(events->reserved));
 }
 
+static void kvm_set_hflags(struct kvm_vcpu *vcpu, unsigned emul_flags);
+
 static int kvm_vcpu_ioctl_x86_set_vcpu_events(struct kvm_vcpu *vcpu,
                                              struct kvm_vcpu_events *events)
 {
@@ -3106,10 +3108,13 @@ static int kvm_vcpu_ioctl_x86_set_vcpu_events(struct kvm_vcpu *vcpu,
                vcpu->arch.apic->sipi_vector = events->sipi_vector;
 
        if (events->flags & KVM_VCPUEVENT_VALID_SMM) {
+               u32 hflags = vcpu->arch.hflags;
                if (events->smi.smm)
-                       vcpu->arch.hflags |= HF_SMM_MASK;
+                       hflags |= HF_SMM_MASK;
                else
-                       vcpu->arch.hflags &= ~HF_SMM_MASK;
+                       hflags &= ~HF_SMM_MASK;
+               kvm_set_hflags(vcpu, hflags);
+
                vcpu->arch.smi_pending = events->smi.pending;
                if (events->smi.smm_inside_nmi)
                        vcpu->arch.hflags |= HF_SMM_INSIDE_NMI_MASK;