KVM: VMX: Reset mmu context when entering real mode

Resetting an SMP guest will force AP enter real mode (RESET) with
paging enabled in protected mode. While current enter_rmode() can
only handle mode switch from nonpaging mode to real mode which leads
to SMP reboot failure.

Fix by reloading the mmu context on entering real mode.
Signed-off-by: Yaozu (Eddie) Dong <eddie.dong@intel.com>
Signed-off-by: Qing He <qing.he@intel.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

drivers/kvm/mmu.c

@@ -1049,6 +1049,7 @@ int kvm_mmu_reset_context(struct kvm_vcpu *vcpu)
 	destroy_kvm_mmu(vcpu);
 	return init_kvm_mmu(vcpu);
 }
+EXPORT_SYMBOL_GPL(kvm_mmu_reset_context);
 
 int kvm_mmu_load(struct kvm_vcpu *vcpu)
 {

drivers/kvm/vmx.c

@@ -1128,6 +1128,7 @@ static void enter_rmode(struct kvm_vcpu *vcpu)
 	fix_rmode_seg(VCPU_SREG_GS, &vcpu->rmode.gs);
 	fix_rmode_seg(VCPU_SREG_FS, &vcpu->rmode.fs);
 
+	kvm_mmu_reset_context(vcpu);
 	init_rmode_tss(vcpu->kvm);
 }