target-i386: Add NMI interception to SVM

Check for SVM interception prior to injecting an NMI. Tested via the
Jailhouse hypervisor.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Message-Id: <c65877e9a011ee4962931287e59f502c482b8d0b.1522769774.git.jan.kiszka@web.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

target/i386/seg_helper.c

@@ -1337,6 +1337,7 @@ bool x86_cpu_exec_interrupt(CPUState *cs, int interrupt_request)
             ret = true;
         } else if ((interrupt_request & CPU_INTERRUPT_NMI) &&
                    !(env->hflags2 & HF2_NMI_MASK)) {
+            cpu_svm_check_intercept_param(env, SVM_EXIT_NMI, 0, 0);
             cs->interrupt_request &= ~CPU_INTERRUPT_NMI;
             env->hflags2 |= HF2_NMI_MASK;
             do_interrupt_x86_hardirq(env, EXCP02_NMI, 1);