[v3,11/13] ioapic: introduce ioapic_entry_parse() helper

diff --git a/hw/intc/ioapic.c b/hw/intc/ioapic.c
index 92334a6..84e8948 100644
--- a/hw/intc/ioapic.c
+++ b/hw/intc/ioapic.c
@@ -49,18 +49,56 @@  static IOAPICCommonState *ioapics[MAX_IOAPICS];
 /* global variable from ioapic_common.c */
 extern int ioapic_no;
 
+struct ioapic_entry_info {
+    /* fields parsed from IOAPIC entries */
+    uint8_t masked;
+    uint8_t trig_mode;
+    uint16_t dest_idx;
+    uint8_t dest_mode;
+    uint8_t delivery_mode;
+    uint8_t vector;
+
+    /* MSI message generated from above parsed fields */
+    uint32_t addr;
+    uint32_t data;
+};
+
+static void ioapic_entry_parse(uint64_t entry, struct ioapic_entry_info *info)
+{
+    bzero(info, sizeof(*info));
+    info->masked = (entry >> IOAPIC_LVT_MASKED_SHIFT) & 1;
+    info->trig_mode = (entry >> IOAPIC_LVT_TRIGGER_MODE_SHIFT) & 1;
+    /*
+     * By default, this would be dest_id[8] + reserved[8]. When IR
+     * is enabled, this would be interrupt_index[15] +
+     * interrupt_format[1]. This field never means anything, but
+     * only used to generate corresponding MSI.
+     */
+    info->dest_idx = (entry >> IOAPIC_LVT_DEST_IDX_SHIFT) & 0xffff;
+    info->dest_mode = (entry >> IOAPIC_LVT_DEST_MODE_SHIFT) & 1;
+    info->delivery_mode = (entry >> IOAPIC_LVT_DELIV_MODE_SHIFT) \
+        & IOAPIC_DM_MASK;
+    if (info->delivery_mode == IOAPIC_DM_EXTINT) {
+        info->vector = pic_read_irq(isa_pic);
+    } else {
+        info->vector = entry & IOAPIC_VECTOR_MASK;
+    }
+
+    info->addr = APIC_DEFAULT_ADDRESS | \
+        (info->dest_idx << MSI_ADDR_DEST_IDX_SHIFT) | \
+        (info->dest_mode << MSI_ADDR_DEST_MODE_SHIFT);
+    info->data = (info->vector << MSI_DATA_VECTOR_SHIFT) | \
+        (info->trig_mode << MSI_DATA_TRIGGER_SHIFT) | \
+        (info->delivery_mode << MSI_DATA_DELIVERY_MODE_SHIFT);
+}
+
 static void ioapic_service(IOAPICCommonState *s)
 {
     AddressSpace *ioapic_as = PC_MACHINE(qdev_get_machine())->ioapic_as;
-    uint32_t addr, data;
+    struct ioapic_entry_info info;
     uint8_t i;
-    uint8_t trig_mode;
-    uint8_t vector;
-    uint8_t delivery_mode;
     uint32_t mask;
     uint64_t entry;
-    uint16_t dest_idx;
-    uint8_t dest_mode;
 
     for (i = 0; i < IOAPIC_NUM_PINS; i++) {
         mask = 1 << i;
@@ -68,33 +106,18 @@  static void ioapic_service(IOAPICCommonState *s)
             int coalesce = 0;
 
             entry = s->ioredtbl[i];
-            if (!(entry & IOAPIC_LVT_MASKED)) {
-                trig_mode = ((entry >> IOAPIC_LVT_TRIGGER_MODE_SHIFT) & 1);
-                /*
-                 * By default, this would be dest_id[8] +
-                 * reserved[8]. When IR is enabled, this would be
-                 * interrupt_index[15] + interrupt_format[1]. This
-                 * field never means anything, but only used to
-                 * generate corresponding MSI.
-                 */
-                dest_idx = entry >> IOAPIC_LVT_DEST_IDX_SHIFT;
-                dest_mode = (entry >> IOAPIC_LVT_DEST_MODE_SHIFT) & 1;
-                delivery_mode =
-                    (entry >> IOAPIC_LVT_DELIV_MODE_SHIFT) & IOAPIC_DM_MASK;
-                if (trig_mode == IOAPIC_TRIGGER_EDGE) {
+            ioapic_entry_parse(entry, &info);
+            if (!info.masked) {
+                if (info.trig_mode == IOAPIC_TRIGGER_EDGE) {
                     s->irr &= ~mask;
                 } else {
                     coalesce = s->ioredtbl[i] & IOAPIC_LVT_REMOTE_IRR;
                     s->ioredtbl[i] |= IOAPIC_LVT_REMOTE_IRR;
                 }
-                if (delivery_mode == IOAPIC_DM_EXTINT) {
-                    vector = pic_read_irq(isa_pic);
-                } else {
-                    vector = entry & IOAPIC_VECTOR_MASK;
-                }
+
 #ifdef CONFIG_KVM
                 if (kvm_irqchip_is_split()) {
-                    if (trig_mode == IOAPIC_TRIGGER_EDGE) {
+                    if (info.trig_mode == IOAPIC_TRIGGER_EDGE) {
                         kvm_set_irq(kvm_state, i, 1);
                         kvm_set_irq(kvm_state, i, 0);
                     } else {
@@ -111,13 +134,7 @@  static void ioapic_service(IOAPICCommonState *s)
                  * the IOAPIC message into a MSI one, and its
                  * address space will decide whether we need a
                  * translation. */
-                addr = APIC_DEFAULT_ADDRESS | \
-                    (dest_idx << MSI_ADDR_DEST_IDX_SHIFT) |
-                    (dest_mode << MSI_ADDR_DEST_MODE_SHIFT);
-                data = (vector << MSI_DATA_VECTOR_SHIFT) |
-                    (trig_mode << MSI_DATA_TRIGGER_SHIFT) |
-                    (delivery_mode << MSI_DATA_DELIVERY_MODE_SHIFT);
-                stl_le_phys(ioapic_as, addr, data);
+                stl_le_phys(ioapic_as, info.addr, info.data);
             }
         }
     }