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  git clone http://v3vee.org/palacios/palacios.web/palacios.git
This will give you the master branch. You probably want the devel branch or one of the release branches. To switch to the devel branch, simply execute
  cd palacios
  git checkout --track -b devel origin/devel
The other branches are similar.


Cleanup and sanity-checking of OOB accesses and pointer-to-local issues (Coverity...
[palacios.git] / palacios / src / devices / 8259a.c
index bf3a139..25d6fa1 100644 (file)
@@ -162,7 +162,7 @@ struct pic_internal {
     struct {
        int (*ack)(struct guest_info * core, uint32_t irq, void * private_data);
        void * private_data;
-    } irq_ack_cbs[15];
+    } irq_ack_cbs[16];
 
 
     void * router_handle;
@@ -173,53 +173,96 @@ struct pic_internal {
 static void DumpPICState(struct pic_internal *p)
 {
 
-    PrintDebug(VM_NONE, VCORE_NONE, "8259 PIC: master_state=0x%x\n",p->master_state);
-    PrintDebug(VM_NONE, VCORE_NONE, "8259 PIC: master_irr=0x%x\n",p->master_irr);
-    PrintDebug(VM_NONE, VCORE_NONE, "8259 PIC: master_isr=0x%x\n",p->master_isr);
-    PrintDebug(VM_NONE, VCORE_NONE, "8259 PIC: master_imr=0x%x\n",p->master_imr);
+    V3_Print(VM_NONE, VCORE_NONE, "8259 PIC: master_state=0x%x\n",p->master_state);
+    V3_Print(VM_NONE, VCORE_NONE, "8259 PIC: master_irr=0x%x\n",p->master_irr);
+    V3_Print(VM_NONE, VCORE_NONE, "8259 PIC: master_isr=0x%x\n",p->master_isr);
+    V3_Print(VM_NONE, VCORE_NONE, "8259 PIC: master_imr=0x%x\n",p->master_imr);
 
-    PrintDebug(VM_NONE, VCORE_NONE, "8259 PIC: master_ocw2=0x%x\n",p->master_ocw2);
-    PrintDebug(VM_NONE, VCORE_NONE, "8259 PIC: master_ocw3=0x%x\n",p->master_ocw3);
+    V3_Print(VM_NONE, VCORE_NONE, "8259 PIC: master_ocw2=0x%x\n",p->master_ocw2);
+    V3_Print(VM_NONE, VCORE_NONE, "8259 PIC: master_ocw3=0x%x\n",p->master_ocw3);
 
-    PrintDebug(VM_NONE, VCORE_NONE, "8259 PIC: master_icw1=0x%x\n",p->master_icw1);
-    PrintDebug(VM_NONE, VCORE_NONE, "8259 PIC: master_icw2=0x%x\n",p->master_icw2);
-    PrintDebug(VM_NONE, VCORE_NONE, "8259 PIC: master_icw3=0x%x\n",p->master_icw3);
-    PrintDebug(VM_NONE, VCORE_NONE, "8259 PIC: master_icw4=0x%x\n",p->master_icw4);
+    V3_Print(VM_NONE, VCORE_NONE, "8259 PIC: master_icw1=0x%x\n",p->master_icw1);
+    V3_Print(VM_NONE, VCORE_NONE, "8259 PIC: master_icw2=0x%x\n",p->master_icw2);
+    V3_Print(VM_NONE, VCORE_NONE, "8259 PIC: master_icw3=0x%x\n",p->master_icw3);
+    V3_Print(VM_NONE, VCORE_NONE, "8259 PIC: master_icw4=0x%x\n",p->master_icw4);
 
-    PrintDebug(VM_NONE, VCORE_NONE, "8259 PIC: slave_state=0x%x\n",p->slave_state);
-    PrintDebug(VM_NONE, VCORE_NONE, "8259 PIC: slave_irr=0x%x\n",p->slave_irr);
-    PrintDebug(VM_NONE, VCORE_NONE, "8259 PIC: slave_isr=0x%x\n",p->slave_isr);
-    PrintDebug(VM_NONE, VCORE_NONE, "8259 PIC: slave_imr=0x%x\n",p->slave_imr);
+    V3_Print(VM_NONE, VCORE_NONE, "8259 PIC: slave_state=0x%x\n",p->slave_state);
+    V3_Print(VM_NONE, VCORE_NONE, "8259 PIC: slave_irr=0x%x\n",p->slave_irr);
+    V3_Print(VM_NONE, VCORE_NONE, "8259 PIC: slave_isr=0x%x\n",p->slave_isr);
+    V3_Print(VM_NONE, VCORE_NONE, "8259 PIC: slave_imr=0x%x\n",p->slave_imr);
 
-    PrintDebug(VM_NONE, VCORE_NONE, "8259 PIC: slave_ocw2=0x%x\n",p->slave_ocw2);
-    PrintDebug(VM_NONE, VCORE_NONE, "8259 PIC: slave_ocw3=0x%x\n",p->slave_ocw3);
+    V3_Print(VM_NONE, VCORE_NONE, "8259 PIC: slave_ocw2=0x%x\n",p->slave_ocw2);
+    V3_Print(VM_NONE, VCORE_NONE, "8259 PIC: slave_ocw3=0x%x\n",p->slave_ocw3);
 
-    PrintDebug(VM_NONE, VCORE_NONE, "8259 PIC: slave_icw1=0x%x\n",p->slave_icw1);
-    PrintDebug(VM_NONE, VCORE_NONE, "8259 PIC: slave_icw2=0x%x\n",p->slave_icw2);
-    PrintDebug(VM_NONE, VCORE_NONE, "8259 PIC: slave_icw3=0x%x\n",p->slave_icw3);
-    PrintDebug(VM_NONE, VCORE_NONE, "8259 PIC: slave_icw4=0x%x\n",p->slave_icw4);
+    V3_Print(VM_NONE, VCORE_NONE, "8259 PIC: slave_icw1=0x%x\n",p->slave_icw1);
+    V3_Print(VM_NONE, VCORE_NONE, "8259 PIC: slave_icw2=0x%x\n",p->slave_icw2);
+    V3_Print(VM_NONE, VCORE_NONE, "8259 PIC: slave_icw3=0x%x\n",p->slave_icw3);
+    V3_Print(VM_NONE, VCORE_NONE, "8259 PIC: slave_icw4=0x%x\n",p->slave_icw4);
 
 }
 
 
+static int pic_vec_to_irq(struct guest_info *info, struct pic_internal *state, int vec)
+{
+  if ((vec >= state->master_icw2) && (vec <= state->master_icw2 + 7)) {
+    return vec & 0x7;
+  } else if ((vec >= state->slave_icw2) && (vec <= state->slave_icw2 + 7)) {
+    return (vec & 0x7) + 8;
+  } else {
+    // Note that this is not an error since there may also be IOAPICs 
+    PrintDebug(info->vm_info, info, "8259 PIC: Cannot translate vector %d back to an IRQ I support\n",vec);
+    return -1;
+  }
+}
+
+static int pic_irq_to_vec(struct guest_info *info, struct pic_internal *state, int irq)
+{
+  if (irq<0) { 
+    return -1;
+  }
+
+  // This will treat IRQ2 as occuring on the master, 
+  // not on slave IRQ9 as expected for legacy behavior
+  // We shouldn't see anything attempting to raise IRQ2...
+  if (irq==2) { 
+    PrintError(info->vm_info, info, "8259 PIC: Warning - IRQ 2 is being translated...\n");
+  }
+
+  if (irq<=7) { 
+    return irq + state->master_icw2;
+  } else if (irq<=15) { 
+    return (irq-8) + state->slave_icw2;
+  } else {
+    PrintDebug(info->vm_info, info, "8259 PIC: Warning: IRQ %d is being translated, but only IRQs 0..15 are supported\n",irq);
+    return -1;
+  }
+    
+}
+
+
 static int pic_raise_intr(struct v3_vm_info * vm, void * private_data, struct v3_irq * irq) {
     struct pic_internal * state = (struct pic_internal*)private_data;
     uint8_t irq_num = irq->irq;
 
     if (irq_num == 2) {
+        PrintError(vm, VCORE_NONE, "8259 PIC: Warning - IRQ 2 is being raised...\n");
+        // This is the legacy reroute of IRQ2 to IRQ9
        irq_num = 9;
-       state->master_irr |= 0x04;
     }
 
     PrintDebug(vm, VCORE_NONE, "8259 PIC: Raising irq %d in the PIC\n", irq_num);
 
     if (irq_num <= 7) {
-       state->master_irr |= 0x01 << irq_num;
+      state->master_irr |= 0x01 << irq_num;
+      PrintDebug(vm, VCORE_NONE, "8259 PIC: Master: Raising IRQ %d\n",irq_num);
     } else if ((irq_num > 7) && (irq_num < 16)) {
-       state->slave_irr |= 0x01 << (irq_num - 8);
+      state->slave_irr |= 0x01 << (irq_num - 8);
+      state->master_irr |= 0x04;   // immediately signal to the master pin we're attached to
+      PrintDebug(vm, VCORE_NONE, "8259 PIC: Master + Slave: Raising IRQ %d\n",irq_num);
     } else {
-       PrintDebug(vm, VCORE_NONE, "8259 PIC: Invalid IRQ raised (%d)\n", irq_num);
-       return -1;
+      // This is not an error as the system could have other interrupt controllers
+      PrintDebug(vm, VCORE_NONE, "8259 PIC: Ignoring raise of IRQ %d as it is not supported by the PIC\n", irq_num);
+      return 0;
     }
 
     state->irq_ack_cbs[irq_num].ack = irq->ack;
@@ -238,124 +281,207 @@ static int pic_lower_intr(struct v3_vm_info * vm, void * private_data, struct v3
     struct pic_internal * state = (struct pic_internal*)private_data;
     uint8_t irq_num = irq->irq;
 
+    if (irq_num == 2) {
+      PrintError(vm, VCORE_NONE, "8259 PIC: Warning - IRQ 2 is being lowered...\n");
+      // Legacy reroute of IRQ2 to IRQ9
+      irq_num = 9;
+    }
+    
+    PrintDebug(vm, VCORE_NONE, "8259 PIC: [pic_lower_intr] IRQ line %d now low\n", irq_num);
 
-    PrintDebug(vm, VCORE_NONE, "[pic_lower_intr] IRQ line %d now low\n", irq_num);
     if (irq_num <= 7) {
-
+        // master
+        PrintDebug(vm, VCORE_NONE, "8259 PIC: Master: IRQ line %d lowered\n", irq_num);
        state->master_irr &= ~(1 << irq_num);
-       if ((state->master_irr & ~(state->master_imr)) == 0) {
-           PrintDebug(vm, VCORE_NONE, "\t\tFIXME: Master maybe should do sth\n");
-       }
+       // Note that another interrupt may still be in the IRR, but that's OK
+       // We'll recognize it on the next entry
     } else if ((irq_num > 7) && (irq_num < 16)) {
-
+        // slave
+        PrintDebug(vm, VCORE_NONE, "8259 PIC: Slave: IRQ line %d lowered\n", irq_num);
        state->slave_irr &= ~(1 << (irq_num - 8));
        if ((state->slave_irr & (~(state->slave_imr))) == 0) {
-           PrintDebug(vm, VCORE_NONE, "\t\tFIXME: Slave maybe should do sth\n");
+         // If there is no other slave interrupt available, we can
+         // turn off IRQ2 on the master
+          PrintDebug(vm, VCORE_NONE, "8259 PIC: Master: IRQ line 2 also lowered due to no other interrupts pending in slave\n");
+         state->master_irr &= ~(0x04);
        }
+    } else {
+      // This is not an error as the system could have other interrupt controllers
+      PrintDebug(vm, VCORE_NONE, "8259 PIC: Ignoring lower of IRQ %d as it is not supported by the PIC\n",irq_num);
     }
+
     return 0;
 }
 
 
 
-static int pic_intr_pending(struct guest_info * info, void * private_data) {
+static int pic_intr_pending_from_master(struct guest_info * info, void * private_data) {
     struct pic_internal * state = (struct pic_internal*)private_data;
 
-    if ((state->master_irr & ~(state->master_imr)) || 
-       (state->slave_irr & ~(state->slave_imr))) {
-       return 1;
-    }
+    return state->master_irr        // interrupt pending in the master's irr
+       & (~(state->master_imr))    // and is not masked in the master 
+       & (~(state->master_icw3));  // and the pin is not hooked to slave
+}
 
-    return 0;
+static int pic_intr_pending_from_slave(struct guest_info * info, void * private_data) {
+    struct pic_internal * state = (struct pic_internal*)private_data;
+
+    return (!(state->master_imr & 0x4)) &&                // master has slave unmasked and
+              (state->slave_irr & (~(state->slave_imr))); // slave is pending
 }
 
+static int pic_intr_pending(struct guest_info * info, void * private_data) {
+
+    return pic_intr_pending_from_master(info,private_data) || 
+           pic_intr_pending_from_slave(info,private_data);
+}
+
+/*
+  8259 prioritization is oddball since there are two chips.  The 
+  slave chip signals an interrupt through pin 2 of the master chip.  
+  This means that all the slave chip's pins are actually at a higher priority
+  than pins 3..7 of the master.   The scheme is as follows, from highest
+  to lowest priority, including legacy mappings:
+  Master  Slave    Typical Legacy Use
+  --------------------------------------------------------------
+  IRQ0             Timer (8254)
+  IRQ1             Keyboard (8042)
+  IRQ2              ****NOT USED - Slave chip inputs here
+          IRQ8     RTC
+          IRQ9     VGA / previous IRQ2 (or PCI via PIRQ LINK B)
+          IRQ10    unused (or PCI via PIRQ LINK C)
+          IRQ11    unused (or PCI via PIRQ LINK D)
+          IRQ12    PS/2 Mouse (8042)
+          IRQ13    Coprocessor error
+          IRQ14    First IDE controller
+          IRQ15    Second IDE controller
+  IRQ3             Second and Fourth Serial Port (COM2/4)
+  IRQ4             First and Third serial port (COM1/3)
+  IRQ5             Second Parallel Port (or PCI via PIRQ LINK A)
+  IRQ6             Floppy controller
+  IRQ7             First Parallel Port
+
+*/
+
 static int pic_get_intr_number(struct guest_info * info, void * private_data) {
     struct pic_internal * state = (struct pic_internal *)private_data;
     int i = 0;
-    int irq = -1;
+    int vec = -1;
 
     PrintDebug(info->vm_info, info, "8259 PIC: getnum: master_irr: 0x%x master_imr: 0x%x\n", state->master_irr, state->master_imr);
     PrintDebug(info->vm_info, info, "8259 PIC: getnum: slave_irr: 0x%x slave_imr: 0x%x\n", state->slave_irr, state->slave_imr);
 
-    for (i = 0; i < 16; i++) {
-       if (i <= 7) {
-           if (((state->master_irr & ~(state->master_imr)) >> i) & 0x01) {
-               //state->master_isr |= (0x1 << i);
-               // reset the irr
-               //state->master_irr &= ~(0x1 << i);
-               PrintDebug(info->vm_info, info, "8259 PIC: IRQ: %d, master_icw2: %x\n", i, state->master_icw2);
-               irq = i + state->master_icw2;
-               break;
-           }
-       } else {
-           if (((state->slave_irr & ~(state->slave_imr)) >> (i - 8)) & 0x01) {
-               //state->slave_isr |= (0x1 << (i - 8));
-               //state->slave_irr &= ~(0x1 << (i - 8));
-               PrintDebug(info->vm_info, info, "8259 PIC: IRQ: %d, slave_icw2: %x\n", i, state->slave_icw2);
-               irq = (i - 8) + state->slave_icw2;
-               break;
-           }
+    // First, see if we have something upstream of the slave
+    for (i=0;i<2;i++) {
+      // Interrupt requested and not masked
+      if (((state->master_irr & ~(state->master_imr)) >> i) & 0x01) {
+       PrintDebug(info->vm_info, info, "8259 PIC: IRQ: %d, master_icw2: %x\n", i, state->master_icw2);
+       vec = pic_irq_to_vec(info, state, i);
+       if (vec<0) { 
+         PrintError(info->vm_info, info, "8259 PIC: Master Interrupt Ready, but vector=%d\n",vec); 
+       }
+       break;
+      }
+    }
+    
+    // Next, the slave
+    if (vec<0 &&                      // Nothing upstream and
+       !(state->master_imr & 0x4)) { // Master is not masking the slave 
+      for (i = 8; i < 16; i++) {
+       if (((state->slave_irr & ~(state->slave_imr)) >> (i - 8)) & 0x01) {
+         PrintDebug(info->vm_info, info, "8259 PIC: IRQ: %d, slave_icw2: %x\n", i, state->slave_icw2);
+         vec = pic_irq_to_vec(info, state, i);
+         if (vec<0) { 
+           PrintError(info->vm_info, info, "8259 PIC: Slave Interrupt Readby, but vector=%d\n",vec); 
+         }
+         break;
        }
+      }
     }
 
-#if 1
-    if ((i == 15) || (i == 6)) { 
-       DumpPICState(state);
+    // And finally the master downstream of the slave
+    if (vec<0) {
+      for (i = 3; i < 8; i++) {
+       if (((state->master_irr & ~(state->master_imr)) >> i) & 0x01) {
+         PrintDebug(info->vm_info, info, "8259 PIC: IRQ: %d, master_icw2: %x\n", i, state->master_icw2);
+         vec = pic_irq_to_vec(info, state, i);
+         if (vec<0) { 
+           PrintError(info->vm_info, info, "8259 PIC: Master Interrupt Ready in 2nd pass, but vector=%d\n",vec);
+         }
+         break;
+       }
+      }
     }
-#endif
   
-    if (i == 16) { 
-       return -1;
+    if (vec>=0) {
+      PrintDebug(info->vm_info, info, "8259 PIC: get num is returning vector %d\n",vec);
     } else {
-       PrintDebug(info->vm_info, info, "8259 PIC: get num is returning %d\n",irq);
-       return irq;
+      PrintDebug(info->vm_info, info, "8259 PIC: no vector available\n");
     }
+    
+    return vec;
 }
 
 
 
-/* The IRQ number is the number returned by pic_get_intr_number(), not the pin number */
-static int pic_begin_irq(struct guest_info * info, void * private_data, int irq) {
-    struct pic_internal * state = (struct pic_internal*)private_data;
-    
-    if ((irq >= state->master_icw2) && (irq <= state->master_icw2 + 7)) {
-       irq &= 0x7;
-    } else if ((irq >= state->slave_icw2) && (irq <= state->slave_icw2 + 7)) {
-       irq &= 0x7;
-       irq += 8;
+
+/* The vec number is the number returned by pic_get_irq_number(), not the pin number. */
+/* In other words, it's the INT vector the PIC is feeding the processor                */
+static int pic_begin_irq(struct guest_info * info, void * private_data, int vec) {
+  struct pic_internal * state = (struct pic_internal*)private_data;
+  int irq;
+  
+  irq = pic_vec_to_irq(info,state,vec);
+  
+  if (irq<0) { 
+    // Not an error - could be for other interrupt controller
+    PrintDebug(info->vm_info,info,"8259 PIC: Ignoring begin_irq on vector %d since it's not ours\n", vec);
+    return 0;
+  }
+  
+  if (irq <= 7) {
+    // Master
+    PrintDebug(info->vm_info, info, "8259 PIC: Master: Beginning IRQ %d\n",irq);
+    // This should always be true: See pic_get_irq_number
+    if (((state->master_irr & (~(state->master_imr))) >> irq) & 0x01) {
+      // unmasked - let's start it
+      state->master_isr |= (0x1 << irq);
+      // auto reset the request if the elcr has this as edge-triggered
+      if (!(state->master_elcr & (0x1 << irq))) {
+       state->master_irr &= ~(0x1 << irq);
+      }
     } else {
-       //    PrintError(info->vm_info, info, "8259 PIC: Could not find IRQ (0x%x) to Begin\n",irq);
-       return -1;
+      PrintDebug(info->vm_info, info, "8259 PIC: Master: Ignoring begin_irq vector %d since I either do not see it set or have it masked (mnaster_irr=0x%x, master_imr=0x%x\n", irq, state->master_irr, state->master_imr);
     }
-    
-    if (irq <= 7) {
-       // This should always be true: See pic_get_intr_number
-       if (((state->master_irr & ~(state->master_imr)) >> irq) & 0x01) {
-           state->master_isr |= (0x1 << irq);
-
-           if (!(state->master_elcr & (0x1 << irq))) {
-               state->master_irr &= ~(0x1 << irq);
-           }
-       } else {
-          PrintDebug(info->vm_info, info, "8259 PIC: (master) Ignoring begin_irq for %d since I don't own it\n", irq);
-       }
-
+  } else if (irq>=8 && irq<=15)  {
+    // Slave
+    PrintDebug(info->vm_info, info, "8259 PIC: Master + Slave: Beginning IRQ %d\n",irq);
+    // This should always be true: See pic_get_irq_number
+    if (((state->slave_irr & (~(state->slave_imr))) >> (irq - 8)) & 0x01) {
+      // unmasked - so let's start it in the slave
+      state->slave_isr |= (0x1 << (irq - 8));
+      // We must have previously pushed it to the master's irr,
+      // so all we need to do here is put it in service there too
+      state->master_isr |= 0x4; // pin 2 is where the slave attaches
+      
+      // auto-reset the request in the slave if it's marked as edge-triggered
+      if (!(state->slave_elcr & (0x1 << (irq - 8)))) {
+       state->slave_irr &= ~(0x1 << (irq - 8));
+      }
+      
+      // auto-reset the request in pin 2 of the master if it's marked as edge-trigged
+      if (!(state->master_elcr & 0x04)) {
+       state->master_irr &= ~0x04;
+      }
     } else {
-       // This should always be true: See pic_get_intr_number
-       if (((state->slave_irr & ~(state->slave_imr)) >> (irq - 8)) & 0x01) {
-          state->slave_isr |= (0x1 << (irq - 8));
-          
-          if (!(state->slave_elcr & (0x1 << (irq - 8)))) {
-              state->slave_irr &= ~(0x1 << (irq - 8));
-          }
-       } else {
-          PrintDebug(info->vm_info, info, "8259 PIC: (slave) Ignoring begin_irq for %d since I don't own it\n", irq);
-       }
+      PrintDebug(info->vm_info, info, "8259 PIC: Maser + Slave: Ignoring begin_irq for %d since I either don't see it set or I don't own it (master_irr=0x%x, master_imr=0x%x, slave_irr=0x%x, slave_imr=0x%x\n", irq,state->master_irr, state->master_imr, state->slave_irr, state->slave_imr);
     }
+  } else {
+    PrintDebug(info->vm_info, info, "8259 PIC: Ignoring begin_irq for %d since I don't own it\n", irq);
+  }
 
-
-
-    return 0;
+  return 0;
 }
 
 
@@ -383,7 +509,7 @@ static int read_master_port1(struct guest_info * core, ushort_t port, void * dst
     struct pic_internal * state = (struct pic_internal *)priv_data;
 
     if (length != 1) {
-       PrintError(core->vm_info, core, "8259 PIC: Invalid Read length (rd_Master1)\n");
+       PrintError(core->vm_info, core, "8259 PIC: Master: Invalid Read length (rd_Master1)\n");
        return -1;
     }
   
@@ -402,7 +528,7 @@ static int read_master_port2(struct guest_info * core, ushort_t port, void * dst
     struct pic_internal * state = (struct pic_internal *)priv_data;
 
     if (length != 1) {
-       PrintError(core->vm_info, core, "8259 PIC: Invalid Read length (rd_Master2)\n");
+       PrintError(core->vm_info, core, "8259 PIC: Master: Invalid Read length (rd_Master2)\n");
        return -1;
     }
 
@@ -416,7 +542,7 @@ static int read_slave_port1(struct guest_info * core, ushort_t port, void * dst,
     struct pic_internal * state = (struct pic_internal *)priv_data;
 
     if (length != 1) {
-       PrintError(core->vm_info, core, "8259 PIC: Invalid Read length (rd_Slave1)\n");
+       PrintError(core->vm_info, core, "8259 PIC: Slave: Invalid Read length (rd_Slave1)\n");
        return -1;
     }
   
@@ -435,7 +561,7 @@ static int read_slave_port2(struct guest_info * core, ushort_t port, void * dst,
     struct pic_internal * state = (struct pic_internal *)priv_data;
 
     if (length != 1) {
-       PrintError(core->vm_info, core, "8259 PIC: Invalid Read length  (rd_Slave2)\n");
+       PrintError(core->vm_info, core, "8259 PIC: Slave: Invalid Read length  (rd_Slave2)\n");
        return -1;
     }
 
@@ -449,10 +575,10 @@ static int write_master_port1(struct guest_info * core, ushort_t port, void * sr
     struct pic_internal * state = (struct pic_internal *)priv_data;
     uint8_t cw = *(uint8_t *)src;
 
-    PrintDebug(core->vm_info, core, "8259 PIC: Write master port 1 with 0x%x\n",cw);
+    PrintDebug(core->vm_info, core, "8259 PIC: Master: Write port 1 with 0x%x\n",cw);
 
     if (length != 1) {
-        PrintError(core->vm_info, core, "8259 PIC: Invalid Write length (wr_Master1)\n");
+        PrintError(core->vm_info, core, "8259 PIC: Master: Invalid Write length (wr_Master1)\n");
         return -1;
     }
 
@@ -460,7 +586,7 @@ static int write_master_port1(struct guest_info * core, ushort_t port, void * sr
 
     if (IS_ICW1(cw)) {
 
-        PrintDebug(core->vm_info, core, "8259 PIC: Setting ICW1 = %x (wr_Master1)\n", cw);
+        PrintDebug(core->vm_info, core, "8259 PIC: Master: Setting ICW1 = %x (wr_Master1)\n", cw);
 
         state->master_icw1 = cw;
         state->master_state = ICW2;
@@ -469,13 +595,14 @@ static int write_master_port1(struct guest_info * core, ushort_t port, void * sr
         if (IS_OCW2(cw)) {
             // handle the EOI here
             struct ocw2 * cw2 =  (struct ocw2*)&cw;
+           int eoi_irq=-1;
 
-            PrintDebug(core->vm_info, core, "8259 PIC: Handling OCW2 = %x (wr_Master1)\n", cw);
+            PrintDebug(core->vm_info, core, "8259 PIC: Master: Handling OCW2 = %x (wr_Master1)\n", cw);
 
             if ((cw2->EOI) && (!cw2->R) && (cw2->SL)) {
                 // specific EOI;
                 state->master_isr &= ~(0x01 << cw2->level);
-
+               eoi_irq = cw2->level;
 
                /*
                // ack the irq if requested
@@ -487,56 +614,69 @@ static int write_master_port1(struct guest_info * core, ushort_t port, void * sr
             } else if ((cw2->EOI) & (!cw2->R) && (!cw2->SL)) {
                 int i;
                 // Non-specific EOI
-                PrintDebug(core->vm_info, core, "8259 PIC: Pre ISR = %x (wr_Master1)\n", state->master_isr);
+                PrintDebug(core->vm_info, core, "8259 PIC: Master: Pre ISR = %x (wr_Master1)\n", state->master_isr);
                 for (i = 0; i < 8; i++) {
                     if (state->master_isr & (0x01 << i)) {
                         state->master_isr &= ~(0x01 << i);
+                       eoi_irq=i;
                         break;
                     }
                 }
-                PrintDebug(core->vm_info, core, "8259 PIC: Post ISR = %x (wr_Master1)\n", state->master_isr);
+               if (i==8) { 
+                 PrintDebug(core->vm_info, core, "8259 PIC: Master: Strange... non-specific EOI but no in-service interrupts\n");
+               }
+               
+                PrintDebug(core->vm_info, core, "8259 PIC: Master: Post ISR = %x (wr_Master1)\n", state->master_isr);
             } else if (!(cw2->EOI) && (cw2->R) && (cw2->SL)) {
-                PrintDebug(core->vm_info, core, "8259 PIC: Ignoring set-priority, priorities not implemented (level=%d, wr_Master1)\n", cw2->level);
+                PrintDebug(core->vm_info, core, "8259 PIC: Master: Ignoring set-priority, priorities not implemented (level=%d, wr_Master1)\n", cw2->level);
             } else if (!(cw2->EOI) && !(cw2->R) && (cw2->SL)) {
-                PrintDebug(core->vm_info, core, "8259 PIC: Ignoring no-op (level=%d, wr_Master1)\n", cw2->level);
+                PrintDebug(core->vm_info, core, "8259 PIC: Master: Ignoring no-op (level=%d, wr_Master1)\n", cw2->level);
            } else {
-                PrintError(core->vm_info, core, "8259 PIC: Command not handled, or in error (wr_Master1)\n");
+                PrintError(core->vm_info, core, "8259 PIC: Master: Command not handled, or in error (wr_Master1)\n");
                 return -1;
             }
 
            if (cw2->EOI) {
-               if (pic_get_intr_number(core,  state) != -1) {
-                   PrintError(core->vm_info, core, "Interrupt pending after EOI\n");
+             if (pic_intr_pending_from_master(core,state)) {
+               // this is perfectly fine as there may be other latched interrupts
+               // but it would be strange if the one we just cleared is suddenly
+               // alive again - well, depending on concurrent behavior external to 
+               int irq = pic_vec_to_irq(core,state,pic_get_intr_number(core,state));
+
+               if (irq == eoi_irq) { 
+          // Not necessarily an error, since it could have been raised again in another thread...
+                 PrintError(core->vm_info, core, "8259 PIC: Master: IRQ %d pending after EOI of IRQ %d\n", irq,eoi_irq);
+                 DumpPICState(state);
                }
+             }
            }
-
-
+           
             state->master_ocw2 = cw;
         } else if (IS_OCW3(cw)) {
-            PrintDebug(core->vm_info, core, "8259 PIC: Handling OCW3 = %x (wr_Master1)\n", cw);
-            state->master_ocw3 = cw;
+         PrintDebug(core->vm_info, core, "8259 PIC: Master: Handling OCW3 = %x (wr_Master1)\n", cw);
+         state->master_ocw3 = cw;
         } else {
-            PrintError(core->vm_info, core, "8259 PIC: Invalid OCW to PIC (wr_Master1)\n");
-            PrintError(core->vm_info, core, "8259 PIC: CW=%x\n", cw);
-            return -1;
+         PrintError(core->vm_info, core, "8259 PIC: Master: Invalid OCW to PIC (wr_Master1)\n");
+         PrintError(core->vm_info, core, "8259 PIC: Master: CW=%x\n", cw);
+         return -1;
         }
     } else {
-        PrintError(core->vm_info, core, "8259 PIC: Invalid PIC State (wr_Master1)\n");
-        PrintError(core->vm_info, core, "8259 PIC: CW=%x\n", cw);
-        return -1;
+      PrintError(core->vm_info, core, "8259 PIC: Master: Invalid PIC State (wr_Master1)\n");
+      PrintError(core->vm_info, core, "8259 PIC: Master: CW=%x\n", cw);
+      return -1;
     }
-
+    
     return 1;
 }
 
 static int write_master_port2(struct guest_info * core, ushort_t port, void * src, uint_t length, void * priv_data) {
-    struct pic_internal * state = (struct pic_internal *)priv_data;
-    uint8_t cw = *(uint8_t *)src;    
-
-    PrintDebug(core->vm_info, core, "8259 PIC: Write master port 2 with 0x%x\n",cw);
+  struct pic_internal * state = (struct pic_internal *)priv_data;
+  uint8_t cw = *(uint8_t *)src;    
+  
+  PrintDebug(core->vm_info, core, "8259 PIC: Master: Write master port 2 with 0x%x\n",cw);
 
-    if (length != 1) {
-        PrintError(core->vm_info, core, "8259 PIC: Invalid Write length (wr_Master2)\n");
+  if (length != 1) {
+    PrintError(core->vm_info, core, "8259 PIC: Master: Invalid Write length (wr_Master2)\n");
         return -1;
     }
 
@@ -545,7 +685,7 @@ static int write_master_port2(struct guest_info * core, ushort_t port, void * sr
     if (state->master_state == ICW2) {
         struct icw1 * cw1 = (struct icw1 *)&(state->master_icw1);
 
-        PrintDebug(core->vm_info, core, "8259 PIC: Setting ICW2 = %x (wr_Master2)\n", cw);
+        PrintDebug(core->vm_info, core, "8259 PIC: Master: Setting ICW2 = %x (wr_Master2)\n", cw);
         state->master_icw2 = cw;
 
 
@@ -563,7 +703,7 @@ static int write_master_port2(struct guest_info * core, ushort_t port, void * sr
     } else if (state->master_state == ICW3) {
         struct icw1 * cw1 = (struct icw1 *)&(state->master_icw1);
 
-        PrintDebug(core->vm_info, core, "8259 PIC: Setting ICW3 = %x (wr_Master2)\n", cw);
+        PrintDebug(core->vm_info, core, "8259 PIC: Master: Setting ICW3 = %x (wr_Master2)\n", cw);
 
         state->master_icw3 = cw;
 
@@ -574,15 +714,15 @@ static int write_master_port2(struct guest_info * core, ushort_t port, void * sr
         }
 
     } else if (state->master_state == ICW4) {
-        PrintDebug(core->vm_info, core, "8259 PIC: Setting ICW4 = %x (wr_Master2)\n", cw);
+        PrintDebug(core->vm_info, core, "8259 PIC: Master: Setting ICW4 = %x (wr_Master2)\n", cw);
         state->master_icw4 = cw;
         state->master_state = READY;
     } else if ((state->master_state == ICW1) || (state->master_state == READY)) {
-        PrintDebug(core->vm_info, core, "8259 PIC: Setting IMR = %x (wr_Master2)\n", cw);
+        PrintDebug(core->vm_info, core, "8259 PIC: Master: Setting IMR = %x (wr_Master2)\n", cw);
         state->master_imr = cw;
     } else {
         // error
-        PrintError(core->vm_info, core, "8259 PIC: Invalid master PIC State (wr_Master2) (state=%d)\n", 
+        PrintError(core->vm_info, core, "8259 PIC: Master: Invalid master PIC State (wr_Master2) (state=%d)\n", 
                 state->master_state);
         return -1;
     }
@@ -594,65 +734,84 @@ static int write_slave_port1(struct guest_info * core, ushort_t port, void * src
     struct pic_internal * state = (struct pic_internal *)priv_data;
     uint8_t cw = *(uint8_t *)src;
 
-    PrintDebug(core->vm_info, core, "8259 PIC: Write slave port 1 with 0x%x\n",cw);
+    PrintDebug(core->vm_info, core, "8259 PIC: Slave: Write slave port 1 with 0x%x\n",cw);
 
     if (length != 1) {
        // error
-       PrintError(core->vm_info, core, "8259 PIC: Invalid Write length (wr_Slave1)\n");
+       PrintError(core->vm_info, core, "8259 PIC: Slave: Invalid Write length (wr_Slave1)\n");
        return -1;
     }
 
     v3_clear_pending_intr(core);
 
     if (IS_ICW1(cw)) {
-       PrintDebug(core->vm_info, core, "8259 PIC: Setting ICW1 = %x (wr_Slave1)\n", cw);
+       PrintDebug(core->vm_info, core, "8259 PIC: Slave: Setting ICW1 = %x (wr_Slave1)\n", cw);
        state->slave_icw1 = cw;
        state->slave_state = ICW2;
     } else if (state->slave_state == READY) {
        if (IS_OCW2(cw)) {
+           int eoi_irq = -1;
            // handle the EOI here
            struct ocw2 * cw2 =  (struct ocw2 *)&cw;
 
-           PrintDebug(core->vm_info, core, "8259 PIC: Setting OCW2 = %x (wr_Slave1)\n", cw);
+           PrintDebug(core->vm_info, core, "8259 PIC: Slave: Setting OCW2 = %x (wr_Slave1)\n", cw);
 
            if ((cw2->EOI) && (!cw2->R) && (cw2->SL)) {
                // specific EOI;
                state->slave_isr &= ~(0x01 << cw2->level);
+               eoi_irq = 8+cw2->level;
            } else if ((cw2->EOI) & (!cw2->R) && (!cw2->SL)) {
                int i;
                // Non-specific EOI
-               PrintDebug(core->vm_info, core, "8259 PIC: Pre ISR = %x (wr_Slave1)\n", state->slave_isr);
+               PrintDebug(core->vm_info, core, "8259 PIC: Slave: Pre ISR = %x (wr_Slave1)\n", state->slave_isr);
                for (i = 0; i < 8; i++) {
                    if (state->slave_isr & (0x01 << i)) {
                        state->slave_isr &= ~(0x01 << i);
+                       eoi_irq=8+i;
                        break;
                    }
                }
-               PrintDebug(core->vm_info, core, "8259 PIC: Post ISR = %x (wr_Slave1)\n", state->slave_isr);
+               if (i==8) { 
+                 PrintDebug(core->vm_info, core, "8259 PIC: Slave: Strange... non-specific EOI but no in-service interrupts\n");
+               }
+               PrintDebug(core->vm_info, core, "8259 PIC: Slave: Post ISR = %x (wr_Slave1)\n", state->slave_isr);
            } else {
-               PrintError(core->vm_info, core, "8259 PIC: Command not handled or invalid  (wr_Slave1)\n");
+               PrintError(core->vm_info, core, "8259 PIC: Slave: Command not handled or invalid  (wr_Slave1)\n");
                return -1;
            }
 
+           // If we now have no further requested interrupts, 
+           // we are not requesting from the master either
+           if (!(state->slave_irr)) { 
+             state->master_irr &= ~0x04;
+           }
+
            if (cw2->EOI) {
-               if (pic_get_intr_number(core,  state) != -1) {
-                   PrintError(core->vm_info, core, "Interrupt pending after EOI\n");
+               if (pic_intr_pending_from_slave(core,state)) {
+                 // this is perfectly fine as there may be other latched interrupts
+                 // but it would be strange if the one we just cleared is suddenly
+                 // alive again - well, depending on concurrent behavior external to 
+                 int irq = pic_vec_to_irq(core,state,pic_get_intr_number(core,state));
+                 
+                 if (irq == eoi_irq) { 
+                   // Not necessarily an error, since it could have been raised again in another thread.
+            PrintError(core->vm_info, core, "8259 PIC: Slave: IRQ %d pending after EOI of IRQ %d\n", irq,eoi_irq);
+                   DumpPICState(state);
+                 }
                }
            }
 
-
-
            state->slave_ocw2 = cw;
        } else if (IS_OCW3(cw)) {
            // Basically sets the IRR/ISR read flag
-           PrintDebug(core->vm_info, core, "8259 PIC: Setting OCW3 = %x (wr_Slave1)\n", cw);
+           PrintDebug(core->vm_info, core, "8259 PIC: Slave: Setting OCW3 = %x (wr_Slave1)\n", cw);
            state->slave_ocw3 = cw;
        } else {
-           PrintError(core->vm_info, core, "8259 PIC: Invalid command work (wr_Slave1)\n");
+           PrintError(core->vm_info, core, "8259 PIC: Slave: Invalid command work (wr_Slave1)\n");
            return -1;
        }
     } else {
-       PrintError(core->vm_info, core, "8259 PIC: Invalid State writing (wr_Slave1)\n");
+       PrintError(core->vm_info, core, "8259 PIC: Slave: Invalid State writing (wr_Slave1)\n");
        return -1;
     }
 
@@ -663,10 +822,10 @@ static int write_slave_port2(struct guest_info * core, ushort_t port, void * src
     struct pic_internal * state = (struct pic_internal *)priv_data;
     uint8_t cw = *(uint8_t *)src;    
 
-    PrintDebug(core->vm_info, core, "8259 PIC: Write slave port 2 with 0x%x\n",cw);
+    PrintDebug(core->vm_info, core, "8259 PIC: Slave: Write slave port 2 with 0x%x\n",cw);
 
     if (length != 1) {
-        PrintError(core->vm_info, core, "8259 PIC: Invalid write length (wr_Slave2)\n");
+        PrintError(core->vm_info, core, "8259 PIC: Slave: Invalid write length (wr_Slave2)\n");
         return -1;
     }
 
@@ -676,7 +835,7 @@ static int write_slave_port2(struct guest_info * core, ushort_t port, void * src
     if (state->slave_state == ICW2) {
         struct icw1 * cw1 =  (struct icw1 *)&(state->master_icw1);
 
-        PrintDebug(core->vm_info, core, "8259 PIC: Setting ICW2 = %x (wr_Slave2)\n", cw);
+        PrintDebug(core->vm_info, core, "8259 PIC: Slave: Setting ICW2 = %x (wr_Slave2)\n", cw);
 
         state->slave_icw2 = cw;
 
@@ -691,7 +850,7 @@ static int write_slave_port2(struct guest_info * core, ushort_t port, void * src
     } else if (state->slave_state == ICW3) {
         struct icw1 * cw1 =  (struct icw1 *)&(state->master_icw1);
 
-        PrintDebug(core->vm_info, core, "8259 PIC: Setting ICW3 = %x (wr_Slave2)\n", cw);
+        PrintDebug(core->vm_info, core, "8259 PIC: Slave: Setting ICW3 = %x (wr_Slave2)\n", cw);
 
         state->slave_icw3 = cw;
 
@@ -702,14 +861,14 @@ static int write_slave_port2(struct guest_info * core, ushort_t port, void * src
         }
 
     } else if (state->slave_state == ICW4) {
-        PrintDebug(core->vm_info, core, "8259 PIC: Setting ICW4 = %x (wr_Slave2)\n", cw);
+        PrintDebug(core->vm_info, core, "8259 PIC: Slave: Setting ICW4 = %x (wr_Slave2)\n", cw);
         state->slave_icw4 = cw;
         state->slave_state = READY;
     } else if ((state->slave_state == ICW1) || (state->slave_state == READY)) {
-        PrintDebug(core->vm_info, core, "8259 PIC: Setting IMR = %x (wr_Slave2)\n", cw);
+        PrintDebug(core->vm_info, core, "8259 PIC: Slave: Setting IMR = %x (wr_Slave2)\n", cw);
         state->slave_imr = cw;
     } else {
-        PrintError(core->vm_info, core, "8259 PIC: Invalid State at write (wr_Slave2)\n");
+        PrintError(core->vm_info, core, "8259 PIC: Slave: Invalid State at write (wr_Slave2)\n");
         return -1;
     }
 
@@ -723,7 +882,7 @@ static int read_elcr_port(struct guest_info * core, ushort_t port, void * dst, u
     struct pic_internal * state = (struct pic_internal *)priv_data;
     
     if (length != 1) {
-       PrintError(core->vm_info, core, "ELCR read of invalid length %d\n", length);
+       PrintError(core->vm_info, core, "8259 PIC: ELCR read of invalid length %d\n", length);
        return -1;
     }
 
@@ -733,7 +892,7 @@ static int read_elcr_port(struct guest_info * core, ushort_t port, void * dst, u
     } else if (port == ELCR2_PORT) {
        *(uint8_t *)dst = state->slave_elcr;
     } else {
-       PrintError(core->vm_info, core, "Invalid port %x\n", port);
+       PrintError(core->vm_info, core, "8259 PIC: Invalid port %x\n", port);
        return -1;
     }
 
@@ -745,7 +904,7 @@ static int write_elcr_port(struct guest_info * core, ushort_t port, void * src,
     struct pic_internal * state = (struct pic_internal *)priv_data;
     
     if (length != 1) {
-       PrintError(core->vm_info, core, "ELCR read of invalid length %d\n", length);
+       PrintError(core->vm_info, core, "8259 PIC: ELCR read of invalid length %d\n", length);
        return -1;
     }
 
@@ -755,7 +914,7 @@ static int write_elcr_port(struct guest_info * core, ushort_t port, void * src,
     } else if (port == ELCR2_PORT) {
        state->slave_elcr  = (*(uint8_t *)src) & state->slave_elcr_mask;
     } else {
-       PrintError(core->vm_info, core, "Invalid port %x\n", port);
+       PrintError(core->vm_info, core, "8259 PIC: Invalid port %x\n", port);
        return -1;
     }
 
@@ -891,14 +1050,14 @@ static int pic_init(struct v3_vm_info * vm, v3_cfg_tree_t * cfg) {
     state = (struct pic_internal *)V3_Malloc(sizeof(struct pic_internal));
 
     if (!state) {
-        PrintError(vm, VCORE_NONE, "Cannot allocate in init\n");
+        PrintError(vm, VCORE_NONE, "8259 PIC: Cannot allocate in init\n");
        return -1;
     }
 
     struct vm_device * dev = v3_add_device(vm, dev_id, &dev_ops, state);
 
     if (dev == NULL) {
-       PrintError(vm, VCORE_NONE, "Could not add device %s\n", dev_id);
+       PrintError(vm, VCORE_NONE, "8259 PIC: Could not add device %s\n", dev_id);
        V3_Free(state);
        return -1;
     }
@@ -946,7 +1105,7 @@ static int pic_init(struct v3_vm_info * vm, v3_cfg_tree_t * cfg) {
     ret |= v3_dev_hook_io(dev, ELCR2_PORT, &read_elcr_port, &write_elcr_port);
 
     if (ret != 0) {
-        PrintError(vm, VCORE_NONE, "Error hooking io ports\n");
+        PrintError(vm, VCORE_NONE, "8259 PIC: Error hooking io ports\n");
        v3_remove_device(dev);
        return -1;
     }