X-Git-Url: http://v3vee.org/palacios/gitweb/gitweb.cgi?a=blobdiff_plain;f=palacios%2Fsrc%2Fpalacios%2Fvmx.c;h=20c0c5f9ac3e56f6abe648cde0047f5c677ed3e6;hb=cf780b903a02efc700d51dbadcc90115f016256c;hp=f26a1eae40cd2154b5878e9b6ef48bb6239cb701;hpb=5d67a000f2d9e0043237af7c86eecd034119fe93;p=palacios.releases.git

diff --git a/palacios/src/palacios/vmx.c b/palacios/src/palacios/vmx.c
index f26a1ea..20c0c5f 100644
--- a/palacios/src/palacios/vmx.c
+++ b/palacios/src/palacios/vmx.c
@@ -212,23 +212,25 @@ static int init_vmcs_bios(struct guest_info * core, struct vmx_data * vmx_state)
 
 
 #ifdef __V3_64BIT__
+    // Ensure host runs in 64-bit mode at each VM EXIT
     vmx_state->exit_ctrls.host_64_on = 1;
 #endif
 
-
-    /* Not sure how exactly to handle this... */
+    // Hook all accesses to EFER register
     v3_hook_msr(core->vm_info, EFER_MSR, 
 		&v3_handle_efer_read,
 		&v3_handle_efer_write, 
 		core);
 
-    // Or is it this??? 
-    vmx_state->entry_ctrls.ld_efer = 1;
+    // Restore host's EFER register on each VM EXIT
     vmx_state->exit_ctrls.ld_efer = 1;
+
+    // Save/restore guest's EFER register to/from VMCS on VM EXIT/ENTRY
     vmx_state->exit_ctrls.save_efer = 1;
-    /*   ***   */
+    vmx_state->entry_ctrls.ld_efer  = 1;
 
-    vmx_ret |= check_vmcs_write(VMCS_CR4_MASK, CR4_VMXE);
+    // Cause VM_EXIT whenever CR4.VMXE or CR4.PAE bits are written
+    vmx_ret |= check_vmcs_write(VMCS_CR4_MASK, CR4_VMXE | CR4_PAE);
 
 
     /* Setup paging */
@@ -749,9 +751,10 @@ 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 +845,6 @@ 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);