From: Patrick G. Bridges <bridges@cs.unm.edu>
Date: Thu, 9 Feb 2012 20:44:53 +0000 (-0700)
Subject: Cleanup to start proper time dilation mechanisms
X-Git-Url: http://v3vee.org/palacios/gitweb/gitweb.cgi?a=commitdiff_plain;h=ff3728843f8471d39cf2ea3511267feb83f14678;p=palacios.git

Cleanup to start proper time dilation mechanisms
---

diff --git a/palacios/include/palacios/vm_guest.h b/palacios/include/palacios/vm_guest.h
index 1ff5899..7dc1344 100644
--- a/palacios/include/palacios/vm_guest.h
+++ b/palacios/include/palacios/vm_guest.h
@@ -67,7 +67,7 @@ struct guest_info {
 
     uint_t cpl;
 
-    struct vm_time time_state;
+    struct vm_core_time time_state;
 
     v3_paging_mode_t shdw_pg_mode;
     struct v3_shdw_pg_state shdw_pg_state;
@@ -166,6 +166,8 @@ struct v3_vm_info {
     /* device_map */
     struct vmm_dev_mgr  dev_mgr;
 
+    struct v3_time time_state;
+
     struct v3_host_events host_event_hooks;
 
     struct v3_config * cfg_data;
diff --git a/palacios/include/palacios/vmm_time.h b/palacios/include/palacios/vmm_time.h
index 7b816a5..0bbb6cc 100644
--- a/palacios/include/palacios/vmm_time.h
+++ b/palacios/include/palacios/vmm_time.h
@@ -31,7 +31,13 @@
 
 struct guest_info;
 
-struct vm_time {
+/* Per-VM time information */
+struct v3_time {
+    uint32_t td_mult; 
+};
+
+/* Per-core time information */
+struct vm_core_time {
     uint32_t host_cpu_freq;    // in kHZ 
     uint32_t guest_cpu_freq;   // can be lower than host CPU freq!
 
@@ -44,6 +50,7 @@ struct vm_time {
     uint64_t initial_time;     // Time when VMM started. 
     uint64_t enter_time;       // Host time the guest was last entered
     uint64_t exit_time;        // Host time the the VM was exited to
+    uint64_t pause_time;       // Time at which the VM core was paused
     struct v3_msr tsc_aux;     // Auxilliary MSR for RDTSCP
 
     // Installed Timers slaved off of the guest monotonic TSC
@@ -90,9 +97,12 @@ int v3_start_time(struct guest_info * core);
 int v3_time_enter_vm(struct guest_info * core);
 int v3_time_exit_vm(struct guest_info * core);
 
-int v3_adjust_time(struct guest_info * core);
+int v3_pause_time(struct guest_info * core);
+int v3_resume_time(struct guest_info * core);
 int v3_offset_time(struct guest_info * core, sint64_t offset);
 
+int v3_adjust_time(struct guest_info * core);
+
 // Basic functions for attaching timers to the passage of time - these timers 
 // should eventually specify their accuracy and resolution.
 struct v3_timer * v3_add_timer(struct guest_info * info, struct v3_timer_ops * ops, void * private_data);
@@ -109,37 +119,35 @@ int v3_schedule_timeout(struct guest_info * info, ullong_t cycles);
 int v3_check_timeout(struct guest_info * info);
 
 // Functions to return the different notions of time in Palacios.
-static inline uint64_t v3_get_host_time(struct vm_time *t) {
+static inline uint64_t v3_get_host_time(struct vm_core_time *t) {
     uint64_t tmp;
     rdtscll(tmp);
     return tmp;
 }
 
 // Returns *monotonic* guest time.
-static inline uint64_t v3_compute_guest_time(struct vm_time *t, uint64_t ht) {
-#ifdef V3_CONFIG_TIME_HIDE_VM_COST
-    V3_ASSERT(t->exit_time);
-    return t->exit_time + t->guest_host_offset;
-#else
-    return ht + t->guest_host_offset;
-#endif
+static inline uint64_t v3_compute_guest_time(struct vm_core_time *t, uint64_t ht) {
+    if (t->pause_time)
+    	return t->pause_time + t->guest_host_offset;
+    else
+    	return ht + t->guest_host_offset;
 }
 
-static inline uint64_t v3_get_guest_time(struct vm_time *t) {
+static inline uint64_t v3_get_guest_time(struct vm_core_time *t) {
     return v3_compute_guest_time(t, v3_get_host_time(t));
 }
 
 // Returns the TSC value seen by the guest
-static inline uint64_t v3_compute_guest_tsc(struct vm_time *t, uint64_t ht) {
+static inline uint64_t v3_compute_guest_tsc(struct vm_core_time *t, uint64_t ht) {
     return v3_compute_guest_time(t, ht) + t->tsc_guest_offset;
 }
 
-static inline uint64_t v3_get_guest_tsc(struct vm_time *t) {
+static inline uint64_t v3_get_guest_tsc(struct vm_core_time *t) {
     return v3_compute_guest_tsc(t, v3_get_host_time(t));
 }
 
 // Returns offset of guest TSC from host TSC
-static inline sint64_t v3_tsc_host_offset(struct vm_time *time_state) {
+static inline sint64_t v3_tsc_host_offset(struct vm_core_time *time_state) {
     return time_state->guest_host_offset + time_state->tsc_guest_offset;
 }
 
diff --git a/palacios/src/palacios/vmm_time.c b/palacios/src/palacios/vmm_time.c
index a3a5e5e..203981d 100644
--- a/palacios/src/palacios/vmm_time.c
+++ b/palacios/src/palacios/vmm_time.c
@@ -76,7 +76,7 @@
 
 
 static int handle_cpufreq_hcall(struct guest_info * info, uint_t hcall_id, void * priv_data) {
-    struct vm_time * time_state = &(info->time_state);
+    struct vm_core_time * time_state = &(info->time_state);
 
     info->vm_regs.rbx = time_state->guest_cpu_freq;
 
@@ -102,9 +102,41 @@ int v3_start_time(struct guest_info * info) {
     return 0;
 }
 
+int v3_pause_time( struct guest_info * info )
+{
+    struct vm_core_time * time_state = &(info->time_state);
+    if (time_state->pause_time != 0) {
+	PrintError("Attempted to pause time when time already paused.\n");
+	return -1;
+    }
+    time_state->pause_time = v3_get_host_time( time_state );
+
+    return 0;
+}
+
+int v3_resume_time( struct guest_info * info )
+{
+    struct vm_core_time * time_state = &(info->time_state);
+    uint64_t host_time, guest_time;
+    sint64_t offset;
+
+    if (time_state->pause_time == 0) {
+	PrintError("Attempted to resume time when time not paused.\n");
+	return -1;
+    }
+
+    host_time = v3_get_host_time(time_state);
+    guest_time = v3_compute_guest_time(time_state, host_time);
+    offset = (sint64_t)guest_time - (sint64_t)host_time;
+    time_state->guest_host_offset = offset;
+    time_state->pause_time = 0;
+
+    return 0;
+}
+
 int v3_offset_time( struct guest_info * info, sint64_t offset )
 {
-    struct vm_time * time_state = &(info->time_state);
+    struct vm_core_time * time_state = &(info->time_state);
     PrintDebug("Adding additional offset of %lld to guest time.\n", offset);
     time_state->guest_host_offset += offset;
     return 0;
@@ -113,7 +145,7 @@ int v3_offset_time( struct guest_info * info, sint64_t offset )
 #ifdef V3_CONFIG_TIME_DILATION
 static uint64_t compute_target_host_time(struct guest_info * info, uint64_t guest_time)
 {
-    struct vm_time * time_state = &(info->time_state);
+    struct vm_core_time * time_state = &(info->time_state);
     uint64_t guest_elapsed, desired_elapsed;
     
     guest_elapsed = (guest_time - time_state->initial_time);
@@ -123,7 +155,7 @@ static uint64_t compute_target_host_time(struct guest_info * info, uint64_t gues
 
 static uint64_t compute_target_guest_time(struct guest_info *info)
 {
-    struct vm_time * time_state = &(info->time_state);
+    struct vm_core_time * time_state = &(info->time_state);
     uint64_t host_elapsed, desired_elapsed;
 
     host_elapsed = v3_get_host_time(time_state) - time_state->initial_time;
@@ -136,7 +168,7 @@ static uint64_t compute_target_guest_time(struct guest_info *info)
 /* Yield time in the host to deal with a guest that wants to run slower than 
  * the native host cycle frequency */
 static int yield_host_time(struct guest_info * info) {
-    struct vm_time * time_state = &(info->time_state);
+    struct vm_core_time * time_state = &(info->time_state);
     uint64_t host_time, target_host_time;
     uint64_t guest_time, old_guest_time;
 
@@ -164,7 +196,7 @@ static int yield_host_time(struct guest_info * info) {
 }
 
 static int skew_guest_time(struct guest_info * info) {
-    struct vm_time * time_state = &(info->time_state);
+    struct vm_core_time * time_state = &(info->time_state);
     uint64_t target_guest_time, guest_time;
     /* Now the host may have gotten ahead of the guest because
      * yielding is a coarse grained thing. Figure out what guest time
@@ -220,10 +252,14 @@ int v3_adjust_time(struct guest_info * info) {
 int 
 v3_time_exit_vm( struct guest_info * info ) 
 {
-    struct vm_time * time_state = &(info->time_state);
+    struct vm_core_time * time_state = &(info->time_state);
     
     time_state->exit_time = v3_get_host_time(time_state);
 
+#ifdef V3_CONFIG_TIME_DILATION
+    v3_pause_time( info );
+#endif
+
     return 0;
 }
 
@@ -231,22 +267,13 @@ v3_time_exit_vm( struct guest_info * info )
 int 
 v3_time_enter_vm( struct guest_info * info )
 {
-    struct vm_time * time_state = &(info->time_state);
+    struct vm_core_time * time_state = &(info->time_state);
     uint64_t host_time;
 
     host_time = v3_get_host_time(time_state);
     time_state->enter_time = host_time;
 #ifdef V3_CONFIG_TIME_DILATION
-    { 
-        uint64_t guest_time;
-	sint64_t offset;
-        guest_time = v3_compute_guest_time(time_state, host_time);
-	// XXX we probably want to use an inline function to do these
-        // time differences to deal with sign and overflow carefully
-	offset = (sint64_t)guest_time - (sint64_t)host_time;
-	PrintDebug("v3_time_enter_vm: guest time offset %lld from host time.\n", offset);
-        time_state->guest_host_offset = offset;
-    }
+    v3_resume_time( info );
 #else
     time_state->guest_host_offset = 0;
 #endif
@@ -281,7 +308,7 @@ int v3_remove_timer(struct guest_info * info, struct v3_timer * timer) {
 }
 
 void v3_update_timers(struct guest_info * info) {
-    struct vm_time *time_state = &info->time_state;
+    struct vm_core_time *time_state = &info->time_state;
     struct v3_timer * tmp_timer;
     sint64_t cycles;
     uint64_t old_time = info->time_state.last_update;
@@ -319,7 +346,7 @@ v3_remove_timeout_hook(struct guest_info * info, struct v3_timeout_hook * hook)
 }
 
 int v3_schedule_timeout(struct guest_info * info, ullong_t guest_timeout) {
-    struct vm_time *time_state = &info->time_state;
+    struct vm_core_time *time_state = &info->time_state;
     /* Note that virtualization architectures that support it (like newer
      * VMX systems) will turn on an active preemption timeout if 
      * available to get this timeout as closely as possible. Other systems
@@ -331,7 +358,7 @@ int v3_schedule_timeout(struct guest_info * info, ullong_t guest_timeout) {
 }
 
 int v3_check_timeout( struct guest_info * info ) {
-    struct vm_time *time_state = &info->time_state;
+    struct vm_core_time *time_state = &info->time_state;
     if (time_state->next_timeout <= v3_get_guest_time(time_state)) {
 	struct v3_timeout_hook * tmp_timeout;
         time_state->next_timeout = (ullong_t)-1;
@@ -411,7 +438,7 @@ int v3_handle_rdtscp(struct guest_info * info) {
 
 static int tsc_aux_msr_read_hook(struct guest_info *info, uint_t msr_num, 
 				 struct v3_msr *msr_val, void *priv) {
-    struct vm_time * time_state = &(info->time_state);
+    struct vm_core_time * time_state = &(info->time_state);
 
     V3_ASSERT(msr_num == TSC_AUX_MSR);
 
@@ -423,7 +450,7 @@ static int tsc_aux_msr_read_hook(struct guest_info *info, uint_t msr_num,
 
 static int tsc_aux_msr_write_hook(struct guest_info *info, uint_t msr_num, 
 			      struct v3_msr msr_val, void *priv) {
-    struct vm_time * time_state = &(info->time_state);
+    struct vm_core_time * time_state = &(info->time_state);
 
     V3_ASSERT(msr_num == TSC_AUX_MSR);
 
@@ -447,7 +474,7 @@ static int tsc_msr_read_hook(struct guest_info *info, uint_t msr_num,
 
 static int tsc_msr_write_hook(struct guest_info *info, uint_t msr_num,
 			     struct v3_msr msr_val, void *priv) {
-    struct vm_time * time_state = &(info->time_state);
+    struct vm_core_time * time_state = &(info->time_state);
     uint64_t guest_time, new_tsc;
 
     V3_ASSERT(msr_num == TSC_MSR);
@@ -483,6 +510,9 @@ int v3_init_time_vm(struct v3_vm_info * vm) {
     ret = v3_register_hypercall(vm, TIME_CPUFREQ_HCALL, 
 				handle_cpufreq_hcall, NULL);
 
+    PrintDebug("Setting base time dilation factor.\n");
+    vm->time_state.td_mult = 1;
+
     return ret;
 }
 
@@ -494,7 +524,7 @@ void v3_deinit_time_vm(struct v3_vm_info * vm) {
 }
 
 void v3_init_time_core(struct guest_info * info) {
-    struct vm_time * time_state = &(info->time_state);
+    struct vm_core_time * time_state = &(info->time_state);
     v3_cfg_tree_t * cfg_tree = info->core_cfg_data;
     char * khz = NULL;
 
@@ -523,6 +553,9 @@ void v3_init_time_core(struct guest_info * info) {
     time_state->last_update = 0;
     time_state->guest_host_offset = 0;
     time_state->tsc_guest_offset = 0;
+    time_state->enter_time = 0;
+    time_state->exit_time = 0;
+    time_state->pause_time = 0;
 
     INIT_LIST_HEAD(&(time_state->timeout_hooks));
     time_state->next_timeout = (ullong_t)-1;
@@ -536,7 +569,7 @@ void v3_init_time_core(struct guest_info * info) {
 
 
 void v3_deinit_time_core(struct guest_info * core) {
-    struct vm_time * time_state = &(core->time_state);
+    struct vm_core_time * time_state = &(core->time_state);
     struct v3_timer * tmr = NULL;
     struct v3_timer * tmp = NULL;