fix barrier hang w/ unitialized secondary cores

diff --git a/palacios/src/palacios/svm.c b/palacios/src/palacios/svm.c
index a52b4d0..115e19c 100644 (file)
--- a/palacios/src/palacios/svm.c
+++ b/palacios/src/palacios/svm.c
@@ -700,6 +700,9 @@ int v3_start_svm_guest(struct guest_info * info) {
        }
 
        PrintDebug("SVM core %u(on %u) initialized\n", info->vcpu_id, info->pcpu_id);
+
+       // We'll be paranoid about race conditions here
+       v3_wait_at_barrier(info);
     } 
 
     PrintDebug("SVM core %u(on %u): I am starting at CS=0x%x (base=0x%p, limit=0x%x),  RIP=0x%p\n", 

diff --git a/palacios/src/palacios/vmm_barrier.c b/palacios/src/palacios/vmm_barrier.c
index ab0aae4..7718fc8 100644 (file)
--- a/palacios/src/palacios/vmm_barrier.c
+++ b/palacios/src/palacios/vmm_barrier.c
@@ -104,6 +104,14 @@ int v3_raise_barrier(struct v3_vm_info * vm_info, struct guest_info * local_core
        all_blocked = 1;
 
        for (i = 0; i < vm_info->num_cores; i++) {
+           
+           // Tricky: If a core is not running then it is safe to ignore it. 
+           // Whenever we transition a core to the RUNNING state we MUST immediately wait on the barrier. 
+           // TODO: Wrap the state transitions in functions that do this automatically
+           if (vm_info->cores[i].core_run_state != CORE_RUNNING) {
+               continue;
+           }
+
            if (v3_bitmap_check(&(barrier->cpu_map), i) == 0) {
                // There is still a core that is not waiting at the barrier
                all_blocked = 0;
@@ -157,6 +165,8 @@ int v3_wait_at_barrier(struct guest_info * core) {
        return 0;
     }
 
+    V3_Print("Core %d waiting at barrier\n", core->vcpu_id);
+
     /*  Barrier has been activated. 
      *  Wait here until it's lowered
      */
@@ -164,6 +174,7 @@ int v3_wait_at_barrier(struct guest_info * core) {
     
     // set cpu bit in barrier bitmap
     v3_bitmap_set(&(barrier->cpu_map), core->vcpu_id);
+    V3_Print("Core %d bit set as waiting\n", core->vcpu_id);
 
     // wait for cpu bit to clear
     while (v3_bitmap_check(&(barrier->cpu_map), core->vcpu_id) == 1) {

diff --git a/palacios/src/palacios/vmx.c b/palacios/src/palacios/vmx.c
index c7c66c5..e733eb5 100644 (file)
--- a/palacios/src/palacios/vmx.c
+++ b/palacios/src/palacios/vmx.c
@@ -955,6 +955,9 @@ int v3_start_vmx_guest(struct guest_info * info) {
         }
        
        PrintDebug("VMX core %u initialized\n", info->vcpu_id);
+
+       // We'll be paranoid about race conditions here
+       v3_wait_at_barrier(info);
     }