X-Git-Url: http://v3vee.org/palacios/gitweb/gitweb.cgi?a=blobdiff_plain;f=palacios%2Fsrc%2Fpalacios%2Fvmm_time.c;h=fa8f5cde8755b15191f1f4683ccab4c82e4b9c01;hb=f88a692d094459f0326c5c891df5ea81b5476ba6;hp=44affe42f5513b2560ca3ae73cda813c7c528fed;hpb=99335f2927daf2c522ecb9ea246fbd68dd2000bb;p=palacios.git

diff --git a/palacios/src/palacios/vmm_time.c b/palacios/src/palacios/vmm_time.c
index 44affe4..fa8f5cd 100644
--- a/palacios/src/palacios/vmm_time.c
+++ b/palacios/src/palacios/vmm_time.c
@@ -18,11 +18,11 @@
  * redistribute, and modify it as specified in the file "V3VEE_LICENSE".
  */
 
-#include <palacios/vmm_time.h>
 #include <palacios/vmm.h>
+#include <palacios/vmm_time.h>
 #include <palacios/vm_guest.h>
 
-#ifndef CONFIG_DEBUG_TIME
+#ifndef V3_CONFIG_DEBUG_TIME
 #undef PrintDebug
 #define PrintDebug(fmt, args...)
 #endif
@@ -86,46 +86,163 @@ int v3_start_time(struct guest_info * info) {
     uint64_t t = v3_get_host_time(&info->time_state); 
 
     PrintDebug("Starting initial guest time as %llu\n", t);
+
+    info->time_state.enter_time = 0;
+    info->time_state.exit_time = t; 
     info->time_state.last_update = t;
     info->time_state.initial_time = t;
     info->yield_start_cycle = t;
+
     return 0;
 }
 
-// If the guest is supposed to run slower than the host, yield out until
-// the host time is appropriately far along;
-int v3_adjust_time(struct guest_info * info) {
+int v3_offset_time( struct guest_info * info, sint64_t offset )
+{
+    struct vm_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;
+}
+
+static uint64_t compute_target_host_time(struct guest_info * info)
+{
+    struct vm_time * time_state = &(info->time_state);
+    uint64_t guest_elapsed, desired_elapsed;
+    
+    guest_elapsed = (v3_get_guest_time(time_state) - time_state->initial_time);
+    desired_elapsed = (guest_elapsed * time_state->host_cpu_freq) / time_state->guest_cpu_freq;
+    return time_state->initial_time + desired_elapsed;
+}
+
+static uint64_t compute_target_guest_time(struct guest_info *info)
+{
     struct vm_time * time_state = &(info->time_state);
+    uint64_t host_elapsed, desired_elapsed;
+
+    host_elapsed = v3_get_host_time(time_state) - time_state->initial_time;
+    desired_elapsed = (host_elapsed * time_state->guest_cpu_freq) / time_state->host_cpu_freq;
 
-    if (time_state->host_cpu_freq == time_state->guest_cpu_freq) {
-	time_state->guest_host_offset = 0;
-    } else {
-	uint64_t guest_time, guest_elapsed, desired_elapsed;
-	uint64_t host_time, target_host_time;
+    return time_state->initial_time + desired_elapsed;
 
-	guest_time = v3_get_guest_time(time_state);
+} 
 
-	/* Compute what host time this guest time should correspond to. */
-	guest_elapsed = (guest_time - time_state->initial_time);
-	desired_elapsed = (guest_elapsed * time_state->host_cpu_freq) / time_state->guest_cpu_freq;
-	target_host_time = time_state->initial_time + desired_elapsed;
+/* 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);
+    uint64_t host_time, target_host_time;
+    uint64_t guest_time, old_guest_time;
 
-	/* Yield until that host time is reached */
+    /* Compute the target host time given how much time has *already*
+     * passed in the guest */
+    target_host_time = compute_target_host_time(info);
+    
+    /* Now, let the host run while the guest is stopped to make the two
+     * sync up. Note that this doesn't assume that guest time is stopped;
+     * the offsetting in the next step will change add an offset to guest
+     * time to account for the time paused even if the geust isn't 
+     * usually paused in the VMM. */
+    host_time = v3_get_host_time(time_state);
+    old_guest_time = v3_get_guest_time(time_state);
+
+    while (target_host_time > host_time) {
+	v3_yield(info);
 	host_time = v3_get_host_time(time_state);
-	while (host_time < target_host_time) {
-	    v3_yield(info);
-	    host_time = v3_get_host_time(time_state);
+    }
+
+    guest_time = v3_get_guest_time(time_state);
+
+    /* We do *not* assume the guest timer was paused in the VM. If it was
+     * this offseting is 0. If it wasn't, we need this. */
+    v3_offset_time(info, (sint64_t)old_guest_time - (sint64_t)guest_time);
+
+    return 0;
+}
+
+static int skew_guest_time(struct guest_info * info) {
+    struct vm_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
+     * we want to be at, and use the use the offsetting mechanism in 
+     * the VMM to make the guest run forward. We limit *how* much we skew 
+     * it forward to prevent the guest time making large jumps, 
+     * however. */
+    target_guest_time = compute_target_guest_time(info);
+    guest_time = v3_get_guest_time(time_state);
+
+    if (guest_time < target_guest_time) {
+	sint64_t max_skew, desired_skew, skew;
+
+	if (time_state->enter_time) {
+	    /* Limit forward skew to 10% of the amount the guest has
+	     * run since we last could skew time */
+	    max_skew = ((sint64_t)guest_time - (sint64_t)time_state->enter_time) / 10;
+	} else {
+	    max_skew = 0;
 	}
 
-	time_state->guest_host_offset = (sint64_t)guest_time - (sint64_t)host_time;
+	desired_skew = (sint64_t)target_guest_time - (sint64_t)guest_time;
+	skew = desired_skew > max_skew ? max_skew : desired_skew;
+	PrintDebug("Guest %lld cycles behind where it should be.\n",
+		   desired_skew);
+	PrintDebug("Limit on forward skew is %lld. Skewing forward %lld.\n",
+	           max_skew, skew); 
+	
+	v3_offset_time(info, skew);
     }
+
     return 0;
 }
 
-int v3_add_timer(struct guest_info * info, struct vm_timer_ops * ops, 
-	     void * private_data) {
-    struct vm_timer * timer = NULL;
-    timer = (struct vm_timer *)V3_Malloc(sizeof(struct vm_timer));
+// Control guest time in relation to host time so that the two stay 
+// appropriately synchronized to the extent possible. 
+int v3_adjust_time(struct guest_info * info) {
+
+    /* First deal with yielding if we want to slow down the guest */
+    yield_host_time(info);
+
+    /* Now, if the guest is too slow, (either from excess yielding above,
+     * or because the VMM is doing something that takes a long time to emulate)
+     * allow guest time to jump forward a bit */
+    skew_guest_time(info);
+    
+    return 0;
+}
+
+/* Called immediately upon entry in the the VMM */
+int 
+v3_time_exit_vm( struct guest_info * info ) 
+{
+    struct vm_time * time_state = &(info->time_state);
+    
+    time_state->exit_time = v3_get_host_time(time_state);
+
+    return 0;
+}
+
+/* Called immediately prior to entry to the VM */
+int 
+v3_time_enter_vm( struct guest_info * info )
+{
+    struct vm_time * time_state = &(info->time_state);
+    uint64_t guest_time, host_time;
+
+    host_time = v3_get_host_time(time_state);
+    guest_time = v3_get_guest_time(time_state);
+    time_state->enter_time = host_time;
+    time_state->guest_host_offset = (sint64_t)guest_time - (sint64_t)host_time;
+
+    return 0;
+}
+	
+
+	   
+struct v3_timer * v3_add_timer(struct guest_info * info, 
+			       struct v3_timer_ops * ops, 
+			       void * private_data) {
+    struct v3_timer * timer = NULL;
+    timer = (struct v3_timer *)V3_Malloc(sizeof(struct v3_timer));
     V3_ASSERT(timer != NULL);
 
     timer->ops = ops;
@@ -134,10 +251,10 @@ int v3_add_timer(struct guest_info * info, struct vm_timer_ops * ops,
     list_add(&(timer->timer_link), &(info->time_state.timers));
     info->time_state.num_timers++;
 
-    return 0;
+    return timer;
 }
 
-int v3_remove_timer(struct guest_info * info, struct vm_timer * timer) {
+int v3_remove_timer(struct guest_info * info, struct v3_timer * timer) {
     list_del(&(timer->timer_link));
     info->time_state.num_timers--;
 
@@ -146,15 +263,18 @@ int v3_remove_timer(struct guest_info * info, struct vm_timer * timer) {
 }
 
 void v3_update_timers(struct guest_info * info) {
-    struct vm_timer * tmp_timer;
+    struct vm_time *time_state = &info->time_state;
+    struct v3_timer * tmp_timer;
     uint64_t old_time = info->time_state.last_update;
-    uint64_t cycles;
+    sint64_t cycles;
 
-    info->time_state.last_update = v3_get_guest_time(&info->time_state);
-    cycles = info->time_state.last_update - old_time;
+    time_state->last_update = v3_get_guest_time(time_state);
+    cycles = time_state->last_update - old_time;
+    V3_ASSERT(cycles >= 0);
 
-    list_for_each_entry(tmp_timer, &(info->time_state.timers), timer_link) {
-	tmp_timer->ops->update_timer(info, cycles, info->time_state.guest_cpu_freq, tmp_timer->private_data);
+    //    V3_Print("Updating timers with %lld elapsed cycles.\n", cycles);
+    list_for_each_entry(tmp_timer, &(time_state->timers), timer_link) {
+	tmp_timer->ops->update_timer(info, cycles, time_state->guest_cpu_freq, tmp_timer->private_data);
     }
 }
 
@@ -169,8 +289,10 @@ void v3_update_timers(struct guest_info * info) {
 
 int v3_rdtsc(struct guest_info * info) {
     uint64_t tscval = v3_get_guest_tsc(&info->time_state);
+
     info->vm_regs.rdx = tscval >> 32;
     info->vm_regs.rax = tscval & 0xffffffffLL;
+
     return 0;
 }
 
@@ -191,21 +313,29 @@ int v3_rdtscp(struct guest_info * info) {
      * ra/c/dx here since they're modified by this instruction anyway. */
     info->vm_regs.rcx = TSC_AUX_MSR; 
     ret = v3_handle_msr_read(info);
-    if (ret) return ret;
+
+    if (ret != 0) {
+	return ret;
+    }
+
     info->vm_regs.rcx = info->vm_regs.rax;
 
     /* Now do the TSC half of the instruction */
     ret = v3_rdtsc(info);
-    if (ret) return ret;
-    
+
+    if (ret != 0) {
+	return ret;
+    }
+
     return 0;
 }
 
 
 int v3_handle_rdtscp(struct guest_info * info) {
+  PrintDebug("Handling virtual RDTSCP call.\n");
 
     v3_rdtscp(info);
-    
+
     info->vm_regs.rax &= 0x00000000ffffffffLL;
     info->vm_regs.rcx &= 0x00000000ffffffffLL;
     info->vm_regs.rdx &= 0x00000000ffffffffLL;
@@ -220,6 +350,7 @@ static int tsc_aux_msr_read_hook(struct guest_info *info, uint_t msr_num,
     struct vm_time * time_state = &(info->time_state);
 
     V3_ASSERT(msr_num == TSC_AUX_MSR);
+
     msr_val->lo = time_state->tsc_aux.lo;
     msr_val->hi = time_state->tsc_aux.hi;
 
@@ -231,6 +362,7 @@ static int tsc_aux_msr_write_hook(struct guest_info *info, uint_t msr_num,
     struct vm_time * time_state = &(info->time_state);
 
     V3_ASSERT(msr_num == TSC_AUX_MSR);
+
     time_state->tsc_aux.lo = msr_val.lo;
     time_state->tsc_aux.hi = msr_val.hi;
 
@@ -242,6 +374,7 @@ static int tsc_msr_read_hook(struct guest_info *info, uint_t msr_num,
     uint64_t time = v3_get_guest_tsc(&info->time_state);
 
     V3_ASSERT(msr_num == TSC_MSR);
+
     msr_val->hi = time >> 32;
     msr_val->lo = time & 0xffffffffLL;
     
@@ -252,7 +385,9 @@ 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);
     uint64_t guest_time, new_tsc;
+
     V3_ASSERT(msr_num == TSC_MSR);
+
     new_tsc = (((uint64_t)msr_val.hi) << 32) | (uint64_t)msr_val.lo;
     guest_time = v3_get_guest_time(time_state);
     time_state->tsc_guest_offset = (sint64_t)new_tsc - (sint64_t)guest_time; 
@@ -261,43 +396,64 @@ static int tsc_msr_write_hook(struct guest_info *info, uint_t msr_num,
 }
 
 
-static int init_vm_time(struct v3_vm_info *vm_info) {
+int v3_init_time_vm(struct v3_vm_info * vm) {
     int ret;
 
     PrintDebug("Installing TSC MSR hook.\n");
-    ret = v3_hook_msr(vm_info, TSC_MSR, 
+    ret = v3_hook_msr(vm, TSC_MSR, 
 		      tsc_msr_read_hook, tsc_msr_write_hook, NULL);
 
+    if (ret != 0) {
+	return ret;
+    }
+
     PrintDebug("Installing TSC_AUX MSR hook.\n");
-    if (ret) return ret;
-    ret = v3_hook_msr(vm_info, TSC_AUX_MSR, tsc_aux_msr_read_hook, 
+    ret = v3_hook_msr(vm, TSC_AUX_MSR, tsc_aux_msr_read_hook, 
 		      tsc_aux_msr_write_hook, NULL);
-    if (ret) return ret;
+
+    if (ret != 0) {
+	return ret;
+    }
 
     PrintDebug("Registering TIME_CPUFREQ hypercall.\n");
-    ret = v3_register_hypercall(vm_info, TIME_CPUFREQ_HCALL, 
+    ret = v3_register_hypercall(vm, TIME_CPUFREQ_HCALL, 
 				handle_cpufreq_hcall, NULL);
+
     return ret;
 }
 
-void v3_init_time(struct guest_info * info) {
+void v3_deinit_time_vm(struct v3_vm_info * vm) {
+    v3_unhook_msr(vm, TSC_MSR);
+    v3_unhook_msr(vm, TSC_AUX_MSR);
+
+    v3_remove_hypercall(vm, TIME_CPUFREQ_HCALL);
+}
+
+void v3_init_time_core(struct guest_info * info) {
     struct vm_time * time_state = &(info->time_state);
     v3_cfg_tree_t * cfg_tree = info->core_cfg_data;
-    static int one_time = 0;
-    char *khz;
+    char * khz = NULL;
 
     time_state->host_cpu_freq = V3_CPU_KHZ();
     khz = v3_cfg_val(cfg_tree, "khz");
+
     if (khz) {
 	time_state->guest_cpu_freq = atoi(khz);
-	PrintDebug("Core %d CPU frequency requested at %d khz.\n", 
-		   info->cpu_id, time_state->guest_cpu_freq);
-    }
+	PrintDebug("Logical Core %d (vcpu=%d) CPU frequency requested at %d khz.\n", 
+		   info->pcpu_id, info->vcpu_id, time_state->guest_cpu_freq);
+    } 
     
-    if (!khz || time_state->guest_cpu_freq > time_state->host_cpu_freq) {
+    if ( (khz == NULL) || 
+	 (time_state->guest_cpu_freq <= 0)  || 
+	 (time_state->guest_cpu_freq > time_state->host_cpu_freq) ) {
+
 	time_state->guest_cpu_freq = time_state->host_cpu_freq;
     }
-    PrintDebug("Core %d CPU frequency set to %d KHz (host CPU frequency = %d KHz).\n", info->cpu_id, time_state->guest_cpu_freq, time_state->host_cpu_freq);
+
+    PrintDebug("Logical Core %d (vcpu=%d) CPU frequency set to %d KHz (host CPU frequency = %d KHz).\n", 
+	       info->pcpu_id, info->vcpu_id,
+	       time_state->guest_cpu_freq, 
+	       time_state->host_cpu_freq);
 
     time_state->initial_time = 0;
     time_state->last_update = 0;
@@ -309,18 +465,16 @@ void v3_init_time(struct guest_info * info) {
     
     time_state->tsc_aux.lo = 0;
     time_state->tsc_aux.hi = 0;
-
-    if (!one_time) {
-	init_vm_time(info->vm_info);
-	one_time = 1;
-    }
 }
 
 
+void v3_deinit_time_core(struct guest_info * core) {
+    struct vm_time * time_state = &(core->time_state);
+    struct v3_timer * tmr = NULL;
+    struct v3_timer * tmp = NULL;
 
+    list_for_each_entry_safe(tmr, tmp, &(time_state->timers), timer_link) {
+	v3_remove_timer(core, tmr);
+    }
 
-
-
-
-
-
+}