[Qemu-devel] [PATCH 3/3] apic: Implement handling of RH=1 for MSI interrupt delivery

[James Sullivan <sullivan.james.f@gmail.com>]

Added argument to apic_get_delivery_bitmask() for msi_redir_hint,
and changed calls to the function accordingly (using 0 as a default
value for non-MSI interrupts).

Modified the implementation of apic_get_delivery_bitmask() to account
for the RH bit of an MSI IRQ. The RH bit indicates that the message
should target only the lowest-priority processor among those specified
by the logical destination of the IRQ.

Signed-off-by: James Sullivan <sullivan.james.f@gmail.com>
---
 hw/intc/apic.c | 34 ++++++++++++++++++++--------------
 1 file changed, 20 insertions(+), 14 deletions(-)

diff --git a/hw/intc/apic.c b/hw/intc/apic.c
index 97dd649..7ac60aa 100644
--- a/hw/intc/apic.c
+++ b/hw/intc/apic.c
@@ -37,7 +37,8 @@ static APICCommonState *local_apics[MAX_APICS + 1];
 static void apic_set_irq(APICCommonState *s, int vector_num, int trigger_mode);
 static void apic_update_irq(APICCommonState *s);
 static void apic_get_delivery_bitmask(uint32_t *deliver_bitmask,
-                                      uint8_t dest, uint8_t dest_mode);
+                                      uint8_t dest, uint8_t dest_mode,
+                                      uint8_t msi_redir_hint);
 
 /* Find first bit starting from msb */
 static int apic_fls_bit(uint32_t value)
@@ -314,7 +315,7 @@ void apic_deliver_irq(uint8_t dest, uint8_t dest_mode, uint8_t delivery_mode,
     trace_apic_deliver_irq(dest, dest_mode, delivery_mode, vector_num,
                            trigger_mode, msi_redir_hint);
 
-    apic_get_delivery_bitmask(deliver_bitmask, dest, dest_mode);
+    apic_get_delivery_bitmask(deliver_bitmask, dest, dest_mode, msi_redir_hint);
     apic_bus_deliver(deliver_bitmask, delivery_mode, vector_num, trigger_mode);
 }
 
@@ -472,7 +473,8 @@ static int apic_find_dest(uint8_t dest)
 }
 
 static void apic_get_delivery_bitmask(uint32_t *deliver_bitmask,
-                                      uint8_t dest, uint8_t dest_mode)
+                                      uint8_t dest, uint8_t dest_mode,
+                                      uint8_t msi_redir_hint)
 {
     APICCommonState *apic_iter;
     int i;
@@ -488,23 +490,27 @@ static void apic_get_delivery_bitmask(uint32_t *deliver_bitmask,
         }
     } else {
         /* XXX: cluster mode */
+        int l = -1;
         memset(deliver_bitmask, 0x00, MAX_APIC_WORDS * sizeof(uint32_t));
         for(i = 0; i < MAX_APICS; i++) {
             apic_iter = local_apics[i];
-            if (apic_iter) {
-                if (apic_iter->dest_mode == 0xf) {
-                    if (dest & apic_iter->log_dest)
-                        apic_set_bit(deliver_bitmask, i);
-                } else if (apic_iter->dest_mode == 0x0) {
-                    if ((dest & 0xf0) == (apic_iter->log_dest & 0xf0) &&
-                        (dest & apic_iter->log_dest & 0x0f)) {
-                        apic_set_bit(deliver_bitmask, i);
+            if (!apic_iter) {
+                break;
+            }
+            if (apic_match_dest(apic_iter, dest_mode, dest)) {
+                if (msi_redir_hint) {
+                    if (l < 0 ||
+                        apic_compare_prio(apic_iter, local_apics[l]) < 0) {
+                        l = i;
                     }
+                } else {
+                    apic_set_bit(deliver_bitmask, i);
                 }
-            } else {
-                break;
             }
         }
+        if (msi_redir_hint && l >= 0) {
+            apic_set_bit(deliver_bitmask, l);
+        }
     }
 }
 
@@ -537,7 +543,7 @@ static void apic_deliver(DeviceState *dev, uint8_t dest, uint8_t dest_mode,
 
     switch (dest_shorthand) {
     case 0:
-        apic_get_delivery_bitmask(deliver_bitmask, dest, dest_mode);
+        apic_get_delivery_bitmask(deliver_bitmask, dest, dest_mode, 0);
         break;
     case 1:
         memset(deliver_bitmask, 0x00, sizeof(deliver_bitmask));
-- 
2.3.3