From: Patrick Bridges <bridges@apu.cs.unm.edu>
Date: Tue, 14 Jun 2011 18:57:56 +0000 (-0600)
Subject: More timing cleanup
X-Git-Url: http://v3vee.org/palacios/gitweb/gitweb.cgi?p=palacios.git;a=commitdiff_plain;h=33d86eaa5e5081775fd013466393496b476925b0

More timing cleanup
---

diff --git a/palacios/src/devices/apic.c b/palacios/src/devices/apic.c
index 5d6da5e..508f221 100644
--- a/palacios/src/devices/apic.c
+++ b/palacios/src/devices/apic.c
@@ -1357,6 +1357,8 @@ static int apic_write(struct guest_info * core, addr_t guest_addr, void * src, u
 	    apic->tmr_cur_cnt = op_val;
 	    break;
 	case TMR_DIV_CFG_OFFSET:
+	    PrintDebug("apic %u: core %u: setting tmr_div_cfg to 0x%x\n",
+		       apic->lapic_id.val, core->vcpu_id, op_val);
 	    apic->tmr_div_cfg.val = op_val;
 	    break;
 
@@ -1650,6 +1652,19 @@ static void apic_update_time(struct guest_info * core,
 	}
     
 	if (apic->tmr_vec_tbl.tmr_mode == APIC_TMR_PERIODIC) {
+	    static unsigned int nexits = 0;
+	    static unsigned int missed_ints = 0;
+
+	    nexits++;
+	    missed_ints += tmr_ticks / apic->tmr_init_cnt;
+
+	    if ((missed_ints > 0) && (nexits >= 5000)) {
+	        V3_Print("apic %u: core %u: missed %u timer interrupts total in last %u exits.\n",
+		         apic->lapic_id.val, core->vcpu_id, missed_ints, nexits); 
+		missed_ints = 0;
+		nexits = 0;
+	    }
+
 	    tmr_ticks = tmr_ticks % apic->tmr_init_cnt;
 	    apic->tmr_cur_cnt = apic->tmr_init_cnt - tmr_ticks;
 	}
diff --git a/palacios/src/palacios/svm.c b/palacios/src/palacios/svm.c
index 6e8bece..7d7b43c 100644
--- a/palacios/src/palacios/svm.c
+++ b/palacios/src/palacios/svm.c
@@ -463,9 +463,9 @@ int v3_svm_enter(struct guest_info * info) {
     // disable global interrupts for vm state transition
     v3_clgi();
 
-    // Update timer devices right before entering the VM. Doing it 
-    // here makes sure the guest sees any timers that fired while 
-    // it was in the VMM
+    // Update timer devices after being in the VM, with interupts
+    // disabled, but before doing IRQ updates, so that any interrupts they 
+    //raise get seen immediately.
     v3_update_timers(info);
 
     // Synchronize the guest state to the VMCB
@@ -550,13 +550,11 @@ int v3_svm_enter(struct guest_info * info) {
     info->mem_mode = v3_get_vm_mem_mode(info);
     /* ** */
 
-
     // save exit info here
     exit_code = guest_ctrl->exit_code;
     exit_info1 = guest_ctrl->exit_info1;
     exit_info2 = guest_ctrl->exit_info2;
 
-
 #ifdef V3_CONFIG_SYMCALL
     if (info->sym_core_state.symcall_state.sym_call_active == 0) {
 	update_irq_exit_state(info);
@@ -565,16 +563,12 @@ int v3_svm_enter(struct guest_info * info) {
     update_irq_exit_state(info);
 #endif
 
-
     // reenable global interrupts after vm exit
     v3_stgi();
-
  
     // Conditionally yield the CPU if the timeslice has expired
     v3_yield_cond(info);
 
-
-
     if (v3_handle_svm_exit(info, exit_code, exit_info1, exit_info2) != 0) {
 	PrintError("Error in SVM exit handler\n");
 	PrintError("  last exit was %d\n", v3_last_exit);
diff --git a/palacios/src/palacios/vmx.c b/palacios/src/palacios/vmx.c
index f26a1ea..5963d93 100644
--- a/palacios/src/palacios/vmx.c
+++ b/palacios/src/palacios/vmx.c
@@ -749,9 +749,10 @@ int v3_vmx_enter(struct guest_info * info) {
     // disable global interrupts for vm state transition
     v3_disable_ints();
 
-    // Update timer devices prior to entering VM.  Doing it here 
-    // makes sure the guest sees any timers that fired while it 
-    // was in the VMM
+    // Update timer devices late after being in the VM so that as much 
+    // of hte time in the VM is accounted for as possible. Also do it before
+    // updating IRQ entry state so that any interrupts the timers raise get 
+    // handled on the next VM entry. Must be done with interrupts disabled.
     v3_update_timers(info);
 
     if (vmcs_store() != vmx_info->vmcs_ptr_phys) {
@@ -842,7 +843,6 @@ int v3_vmx_enter(struct guest_info * info) {
 
     exit_log[info->num_exits % 10] = exit_info;
 
-
 #ifdef V3_CONFIG_SYMCALL
     if (info->sym_core_state.symcall_state.sym_call_active == 0) {
 	update_irq_exit_state(info);