Implement APIC IRR interrupt priorities.

Even with kernel-irqchip=off, Hyper-V is aware of interrupt priorities
and implements CR8/TPR, with the InterruptPriority field being followed.

Signed-off-by: Mohamed Mediouni <mohamed@unpredictable.fr>
---
 target/i386/whpx/whpx-all.c | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/target/i386/whpx/whpx-all.c b/target/i386/whpx/whpx-all.c
index 7a31dc6427..8cd81fffee 100644
--- a/target/i386/whpx/whpx-all.c
+++ b/target/i386/whpx/whpx-all.c
@@ -1588,6 +1588,7 @@ static void whpx_vcpu_pre_run(CPUState *cpu)
     UINT32 reg_count = 0;
     WHV_REGISTER_VALUE reg_values[3];
     WHV_REGISTER_NAME reg_names[3];
+    int irr = apic_get_highest_priority_irr(x86_cpu->apic_state);
 
     memset(&new_int, 0, sizeof(new_int));
     memset(reg_values, 0, sizeof(reg_values));
@@ -1623,10 +1624,20 @@ static void whpx_vcpu_pre_run(CPUState *cpu)
         }
     }
 
+    if (irr == -1) {
+        if (pic_get_output(isa_pic)) {
+            /* In case it's a PIC interrupt */
+            irr = 0;
+        } else if (cpu_test_interrupt(cpu, CPU_INTERRUPT_HARD)) {
+            abort();
+        }
+    }
+
     /* Get pending hard interruption or replay one that was overwritten */
     if (!whpx_irqchip_in_kernel()) {
         if (!vcpu->interruption_pending &&
-            vcpu->interruptable && (env->eflags & IF_MASK)) {
+            vcpu->interruptable && (env->eflags & IF_MASK)
+            && (vcpu->tpr < irr || irr == 0)) {
             assert(!new_int.InterruptionPending);
             if (cpu_test_interrupt(cpu, CPU_INTERRUPT_HARD)) {
                 cpu_reset_interrupt(cpu, CPU_INTERRUPT_HARD);
@@ -1683,13 +1694,17 @@ static void whpx_vcpu_pre_run(CPUState *cpu)
     }
 
     /* Update the state of the interrupt delivery notification */
-    if (!vcpu->window_registered &&
+    if ((!vcpu->window_registered ||
+        (vcpu->window_priority < irr && vcpu->window_priority != 0) ||
+        (irr == 0 && vcpu->window_priority != 0)) &&
         cpu_test_interrupt(cpu, CPU_INTERRUPT_HARD)) {
         reg_values[reg_count].DeliverabilityNotifications =
             (WHV_X64_DELIVERABILITY_NOTIFICATIONS_REGISTER) {
-                .InterruptNotification = 1
+                .InterruptNotification = 1,
+                .InterruptPriority = irr >> 4
             };
         vcpu->window_registered = 1;
+        vcpu->window_priority = irr;
         reg_names[reg_count] = WHvX64RegisterDeliverabilityNotifications;
         reg_count += 1;
     }
@@ -1703,7 +1718,7 @@ static void whpx_vcpu_pre_run(CPUState *cpu)
             reg_names, reg_count, reg_values);
         if (FAILED(hr)) {
             error_report("WHPX: Failed to set interrupt state registers,"
-                         " hr=%08lx", hr);
+                         " hr=%08lx, InterruptPriority=%i", hr, irr >> 4);
         }
     }
 }
@@ -1919,6 +1934,7 @@ int whpx_vcpu_run(CPUState *cpu)
         case WHvRunVpExitReasonX64InterruptWindow:
             vcpu->ready_for_pic_interrupt = 1;
             vcpu->window_registered = 0;
+            vcpu->window_priority = 0;
             ret = 0;
             break;
 
-- 
2.50.1 (Apple Git-155)