X-Git-Url: http://v3vee.org/palacios/gitweb/gitweb.cgi?a=blobdiff_plain;f=palacios%2Fsrc%2Fpalacios%2Fvmm_time.c;h=27bb2fc97c00b7feeb1785bfcd58f6b6d75f1e10;hb=0e26b3738daf436ba2d9a088ba620a3583d40de3;hp=2b61391a538a14f14c5ae0bcf70a74e427884db8;hpb=a405b0fca40b6215154e1ccb36a14fb5e7e767d4;p=palacios.git diff --git a/palacios/src/palacios/vmm_time.c b/palacios/src/palacios/vmm_time.c index 2b61391..27bb2fc 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 #include +#include #include -#ifndef CONFIG_DEBUG_TIME +#ifndef V3_CONFIG_DEBUG_TIME #undef PrintDebug #define PrintDebug(fmt, args...) #endif @@ -86,42 +86,162 @@ 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; +} + +#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); + uint64_t guest_elapsed, desired_elapsed; + + guest_elapsed = (guest_time - 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; - 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; + 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; - guest_time = v3_get_guest_time(time_state); + return time_state->initial_time + desired_elapsed; - /* 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 until that host time is reached */ +/* 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; + + /* 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_compute_guest_time(time_state, host_time); + target_host_time = compute_target_host_time(info, old_guest_time); + + 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_compute_guest_time(time_state, host_time); + + /* 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; +} +#endif /* V3_CONFIG_TIME_DILATION */ + +// 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) { + +#ifdef V3_CONFIG_TIME_DILATION + /* 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); +#endif + 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; +#ifdef V3_CONFIG_TIME_DILATION + time_state->guest_host_offset = (sint64_t)guest_time - (sint64_t)host_time; +#else + time_state->guest_host_offset = 0; +#endif + + return 0; +} + + + struct v3_timer * v3_add_timer(struct guest_info * info, struct v3_timer_ops * ops, void * private_data) { @@ -147,15 +267,18 @@ 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 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); } } @@ -170,8 +293,10 @@ 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; } @@ -192,21 +317,29 @@ 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; @@ -221,6 +354,7 @@ 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; @@ -232,6 +366,7 @@ 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; @@ -243,6 +378,7 @@ 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; @@ -253,7 +389,9 @@ 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; @@ -292,7 +430,7 @@ 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); + v3_remove_hypercall(vm, TIME_CPUFREQ_HCALL); } void v3_init_time_core(struct guest_info * info) { @@ -305,16 +443,19 @@ void v3_init_time_core(struct guest_info * info) { 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 == NULL) || (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, + 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); @@ -328,8 +469,6 @@ void v3_init_time_core(struct guest_info * info) { time_state->tsc_aux.lo = 0; time_state->tsc_aux.hi = 0; - - } @@ -343,9 +482,3 @@ void v3_deinit_time_core(struct guest_info * core) { } } - - - - - -