X-Git-Url: http://v3vee.org/palacios/gitweb/gitweb.cgi?a=blobdiff_plain;f=palacios%2Fsrc%2Fpalacios%2Fvmm_time.c;h=51fbba7e9b022f61320875752cf49420b6dc6720;hb=11799589ba31ee388d35ec764cd69e837880ba08;hp=dc49b1b485757a1f32aeaf210e8d5ddf3af4b0c5;hpb=69982930e8a2c0e44aeae5a95497fb896dad3da3;p=palacios.git diff --git a/palacios/src/palacios/vmm_time.c b/palacios/src/palacios/vmm_time.c index dc49b1b..51fbba7 100644 --- a/palacios/src/palacios/vmm_time.c +++ b/palacios/src/palacios/vmm_time.c @@ -41,25 +41,38 @@ * the passage of time: * (1) The host timestamp counter - read directly from HW and never written * (2) A monotonic guest timestamp counter used to measure the progression of - * time in the guest. This is computed as a multipler/offset from (1) above + * time in the guest. This is computed using an offsets from (1) above. * (3) The actual guest timestamp counter (which can be written by * writing to the guest TSC MSR - MSR 0x10) from the monotonic guest TSC. * This is also computed as an offset from (2) above when the TSC and * this offset is updated when the TSC MSR is written. * + * The value used to offset the guest TSC from the host TSC is the *sum* of all + * of these offsets (2 and 3) above + * * Because all other devices are slaved off of the passage of time in the guest, * it is (2) above that drives the firing of other timers in the guest, * including timer devices such as the Programmable Interrupt Timer (PIT). * - * - * + * Future additions: + * (1) Add support for temporarily skewing guest time off of where it should + * be to support slack simulation of guests. The idea is that simulators + * set this skew to be the difference between how much time passed for a + * simulated feature and a real implementation of that feature, making + * pass at a different rate from real time on this core. The VMM will then + * attempt to move this skew back towards 0 subject to resolution/accuracy + * constraints from various system timers. + * + * The main effort in doing this will be to get accuracy/resolution + * information from each local timer and to use this to bound how much skew + * is removed on each exit. */ static int handle_cpufreq_hcall(struct guest_info * info, uint_t hcall_id, void * priv_data) { struct vm_time * time_state = &(info->time_state); - info->vm_regs.rbx = time_state->cpu_freq; + info->vm_regs.rbx = time_state->guest_cpu_freq; PrintDebug("Guest request cpu frequency: return %ld\n", (long)info->vm_regs.rbx); @@ -74,35 +87,48 @@ int v3_start_time(struct guest_info * info) { PrintDebug("Starting initial guest time as %llu\n", t); info->time_state.last_update = t; - info->time_state.pause_time = t; + info->time_state.initial_time = t; info->yield_start_cycle = t; return 0; } -int v3_pause_time(struct guest_info * info) { - V3_ASSERT(info->time_state.pause_time == 0); - info->time_state.pause_time = v3_get_guest_time(&info->time_state); - PrintDebug("Time paused at guest time as %llu\n", - info->time_state.pause_time); - 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) { + struct vm_time * time_state = &(info->time_state); + + 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; + + 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; -int v3_resume_time(struct guest_info * info) { - uint64_t t = v3_get_host_time(&info->time_state); - V3_ASSERT(info->time_state.pause_time != 0); - info->time_state.time_offset = - (sint64_t)info->time_state.pause_time - (sint64_t)t; - info->time_state.pause_time = 0; - PrintDebug("Time resumed paused at guest time as %llu " - "offset %lld from host time.\n", t, info->time_state.time_offset); + /* Yield until that host time is reached */ + 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); + } + + time_state->guest_host_offset = (sint64_t)guest_time - (sint64_t)host_time; + } 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)); +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; @@ -111,11 +137,10 @@ 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--; @@ -124,7 +149,7 @@ 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 v3_timer * tmp_timer; uint64_t old_time = info->time_state.last_update; uint64_t cycles; @@ -132,16 +157,17 @@ void v3_update_timers(struct guest_info * info) { cycles = info->time_state.last_update - old_time; list_for_each_entry(tmp_timer, &(info->time_state.timers), timer_link) { - tmp_timer->ops->update_timer(info, cycles, info->time_state.cpu_freq, tmp_timer->private_data); + tmp_timer->ops->update_timer(info, cycles, info->time_state.guest_cpu_freq, tmp_timer->private_data); } } - /* * Handle full virtualization of the time stamp counter. As noted * above, we don't store the actual value of the TSC, only the guest's - * offset from the host TSC. If the guest write's the to TSC, we handle - * this by changing that offset. + * offset from monotonic guest's time. If the guest writes to the TSC, we + * handle this by changing that offset. + * + * Possible TODO: Proper hooking of TSC read/writes? */ int v3_rdtsc(struct guest_info * info) { @@ -168,14 +194,20 @@ 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, which may hit the normal - * TSC hook if it exists */ + /* Now do the TSC half of the instruction */ ret = v3_rdtsc(info); - if (ret) return ret; - + + if (ret != 0) { + return ret; + } + return 0; } @@ -198,6 +230,7 @@ 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; @@ -209,6 +242,7 @@ 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; @@ -220,6 +254,7 @@ 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; @@ -230,26 +265,77 @@ 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_time_offset = (sint64_t)new_tsc - (sint64_t)guest_time; + time_state->tsc_guest_offset = (sint64_t)new_tsc - (sint64_t)guest_time; return 0; } -void v3_init_time(struct guest_info * info) { +int v3_init_time_vm(struct v3_vm_info * vm) { + int ret; + + PrintDebug("Installing TSC MSR hook.\n"); + 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"); + ret = v3_hook_msr(vm, TSC_AUX_MSR, tsc_aux_msr_read_hook, + tsc_aux_msr_write_hook, NULL); + + if (ret != 0) { + return ret; + } + + PrintDebug("Registering TIME_CPUFREQ hypercall.\n"); + ret = v3_register_hypercall(vm, TIME_CPUFREQ_HCALL, + handle_cpufreq_hcall, NULL); + + return ret; +} + +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; + char * khz = NULL; + + time_state->host_cpu_freq = V3_CPU_KHZ(); + khz = v3_cfg_val(cfg_tree, "khz"); - time_state->cpu_freq = V3_CPU_KHZ(); - - time_state->pause_time = 0; + 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); + } + + if ((khz == NULL) || (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); + + time_state->initial_time = 0; time_state->last_update = 0; - time_state->time_offset = 0; - time_state->time_div = 1; - time_state->time_mult = 1; - time_state->tsc_time_offset = 0; + time_state->guest_host_offset = 0; + time_state->tsc_guest_offset = 0; INIT_LIST_HEAD(&(time_state->timers)); time_state->num_timers = 0; @@ -257,11 +343,23 @@ void v3_init_time(struct guest_info * info) { time_state->tsc_aux.lo = 0; time_state->tsc_aux.hi = 0; - /* does init_time get called once, or once *per core*??? */ - v3_hook_msr(info->vm_info, TSC_MSR, - tsc_msr_read_hook, tsc_msr_write_hook, NULL); - v3_hook_msr(info->vm_info, TSC_AUX_MSR, tsc_aux_msr_read_hook, - tsc_aux_msr_write_hook, NULL); - v3_register_hypercall(info->vm_info, TIME_CPUFREQ_HCALL, handle_cpufreq_hcall, NULL); } + + +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); + } + +} + + + + + +