target/i386: Added changed priority check for VIRQ

Writes to cr8 affect v_tpr. This could set or unset an interrupt
request as the priority might have changed.

Signed-off-by: Lara Lazier <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>

Author: Lara Lazier

target/i386/cpu.h

@@ -2246,6 +2246,21 @@ static inline uint64_t cr4_reserved_bits(CPUX86State *env)
     return reserved_bits;
 }
 
+static inline bool ctl_has_irq(CPUX86State *env)
+{
+    uint32_t int_prio;
+    uint32_t tpr;
+
+    int_prio = (env->int_ctl & V_INTR_PRIO_MASK) >> V_INTR_PRIO_SHIFT;
+    tpr = env->int_ctl & V_TPR_MASK;
+
+    if (env->int_ctl & V_IGN_TPR_MASK) {
+        return (env->int_ctl & V_IRQ_MASK);
+    }
+
+    return (env->int_ctl & V_IRQ_MASK) && (int_prio >= tpr);
+}
+
 #if defined(TARGET_X86_64) && \
     defined(CONFIG_USER_ONLY) && \
     defined(CONFIG_LINUX)

target/i386/tcg/sysemu/misc_helper.c

@@ -122,6 +122,13 @@ void helper_write_crN(CPUX86State *env, int reg, target_ulong t0)
             qemu_mutex_unlock_iothread();
         }
         env->int_ctl = (env->int_ctl & ~V_TPR_MASK) | (t0 & V_TPR_MASK);
+
+        CPUState *cs = env_cpu(env);
+        if (ctl_has_irq(env)) {
+            cpu_interrupt(cs, CPU_INTERRUPT_VIRQ);
+        } else {
+            cpu_reset_interrupt(cs, CPU_INTERRUPT_VIRQ);
+        }
         break;
     default:
         env->cr[reg] = t0;

target/i386/tcg/sysemu/svm_helper.c

@@ -76,21 +76,6 @@ static inline void svm_load_seg_cache(CPUX86State *env, hwaddr addr,
                            sc->base, sc->limit, sc->flags);
 }
 
-static inline bool ctl_has_irq(CPUX86State *env)
-{
-    uint32_t int_prio;
-    uint32_t tpr;
-
-    int_prio = (env->int_ctl & V_INTR_PRIO_MASK) >> V_INTR_PRIO_SHIFT;
-    tpr = env->int_ctl & V_TPR_MASK;
-
-    if (env->int_ctl & V_IGN_TPR_MASK) {
-        return env->int_ctl & V_IRQ_MASK;
-    }
-
-    return (env->int_ctl & V_IRQ_MASK) && (int_prio >= tpr);
-}
-
 static inline bool is_efer_invalid_state (CPUX86State *env)
 {
     if (!(env->efer & MSR_EFER_SVME)) {