1 /*- 2 * Copyright (c) 2015,2016 Microsoft Corp. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 #include <sys/param.h> 31 #include <sys/bus.h> 32 #include <sys/kernel.h> 33 #include <sys/module.h> 34 #include <sys/proc.h> 35 #include <sys/smp.h> 36 #include <sys/systm.h> 37 #include <sys/timeet.h> 38 39 #include <dev/hyperv/vmbus/hyperv_reg.h> 40 #include <dev/hyperv/vmbus/hyperv_var.h> 41 #include <dev/hyperv/vmbus/vmbus_var.h> 42 43 #define VMBUS_ET_NAME "hvet" 44 45 #define MSR_HV_STIMER0_CFG_SINT \ 46 ((((uint64_t)VMBUS_SINT_TIMER) << MSR_HV_STIMER_CFG_SINT_SHIFT) & \ 47 MSR_HV_STIMER_CFG_SINT_MASK) 48 49 /* 50 * Two additionally required features: 51 * - SynIC is needed for interrupt generation. 52 * - Time reference counter is needed to set ABS reference count to 53 * STIMER0_COUNT. 54 */ 55 #define CPUID_HV_ET_MASK (CPUID_HV_MSR_TIME_REFCNT | \ 56 CPUID_HV_MSR_SYNIC | \ 57 CPUID_HV_MSR_SYNTIMER) 58 59 static void vmbus_et_identify(driver_t *, device_t); 60 static int vmbus_et_probe(device_t); 61 static int vmbus_et_attach(device_t); 62 static int vmbus_et_detach(device_t); 63 static int vmbus_et_start(struct eventtimer *, sbintime_t, 64 sbintime_t); 65 66 static struct eventtimer vmbus_et; 67 68 static device_method_t vmbus_et_methods[] = { 69 DEVMETHOD(device_identify, vmbus_et_identify), 70 DEVMETHOD(device_probe, vmbus_et_probe), 71 DEVMETHOD(device_attach, vmbus_et_attach), 72 DEVMETHOD(device_detach, vmbus_et_detach), 73 74 DEVMETHOD_END 75 }; 76 77 static driver_t vmbus_et_driver = { 78 VMBUS_ET_NAME, 79 vmbus_et_methods, 80 0 81 }; 82 83 static devclass_t vmbus_et_devclass; 84 85 DRIVER_MODULE(hv_et, vmbus, vmbus_et_driver, vmbus_et_devclass, NULL, NULL); 86 MODULE_VERSION(hv_et, 1); 87 88 static __inline uint64_t 89 hyperv_sbintime2count(sbintime_t time) 90 { 91 struct timespec val; 92 93 val = sbttots(time); 94 return (val.tv_sec * HYPERV_TIMER_FREQ) + 95 (val.tv_nsec / HYPERV_TIMER_NS_FACTOR); 96 } 97 98 static int 99 vmbus_et_start(struct eventtimer *et __unused, sbintime_t first, 100 sbintime_t period __unused) 101 { 102 uint64_t current; 103 104 current = rdmsr(MSR_HV_TIME_REF_COUNT); 105 current += hyperv_sbintime2count(first); 106 wrmsr(MSR_HV_STIMER0_COUNT, current); 107 108 return (0); 109 } 110 111 void 112 vmbus_et_intr(struct trapframe *frame) 113 { 114 struct trapframe *oldframe; 115 struct thread *td; 116 117 if (vmbus_et.et_active) { 118 td = curthread; 119 td->td_intr_nesting_level++; 120 oldframe = td->td_intr_frame; 121 td->td_intr_frame = frame; 122 vmbus_et.et_event_cb(&vmbus_et, vmbus_et.et_arg); 123 td->td_intr_frame = oldframe; 124 td->td_intr_nesting_level--; 125 } 126 } 127 128 static void 129 vmbus_et_identify(driver_t *driver, device_t parent) 130 { 131 if (device_get_unit(parent) != 0 || 132 device_find_child(parent, VMBUS_ET_NAME, -1) != NULL || 133 (hyperv_features & CPUID_HV_ET_MASK) != CPUID_HV_ET_MASK) 134 return; 135 136 device_add_child(parent, VMBUS_ET_NAME, -1); 137 } 138 139 static int 140 vmbus_et_probe(device_t dev) 141 { 142 if (resource_disabled(VMBUS_ET_NAME, 0)) 143 return (ENXIO); 144 145 device_set_desc(dev, "Hyper-V event timer"); 146 147 return (BUS_PROBE_NOWILDCARD); 148 } 149 150 static void 151 vmbus_et_config(void *arg __unused) 152 { 153 /* 154 * Make sure that STIMER0 is really disabled before writing 155 * to STIMER0_CONFIG. 156 * 157 * "Writing to the configuration register of a timer that 158 * is already enabled may result in undefined behaviour." 159 */ 160 for (;;) { 161 uint64_t val; 162 163 /* Stop counting, and this also implies disabling STIMER0 */ 164 wrmsr(MSR_HV_STIMER0_COUNT, 0); 165 166 val = rdmsr(MSR_HV_STIMER0_CONFIG); 167 if ((val & MSR_HV_STIMER_CFG_ENABLE) == 0) 168 break; 169 cpu_spinwait(); 170 } 171 wrmsr(MSR_HV_STIMER0_CONFIG, 172 MSR_HV_STIMER_CFG_AUTOEN | MSR_HV_STIMER0_CFG_SINT); 173 } 174 175 static int 176 vmbus_et_attach(device_t dev) 177 { 178 /* TODO: use independent IDT vector */ 179 180 vmbus_et.et_name = "Hyper-V"; 181 vmbus_et.et_flags = ET_FLAGS_ONESHOT | ET_FLAGS_PERCPU; 182 vmbus_et.et_quality = 1000; 183 vmbus_et.et_frequency = HYPERV_TIMER_FREQ; 184 vmbus_et.et_min_period = (0x00000001ULL << 32) / HYPERV_TIMER_FREQ; 185 vmbus_et.et_max_period = (0xfffffffeULL << 32) / HYPERV_TIMER_FREQ; 186 vmbus_et.et_start = vmbus_et_start; 187 188 /* 189 * Delay a bit to make sure that MSR_HV_TIME_REF_COUNT will 190 * not return 0, since writing 0 to STIMER0_COUNT will disable 191 * STIMER0. 192 */ 193 DELAY(100); 194 smp_rendezvous(NULL, vmbus_et_config, NULL, NULL); 195 196 return (et_register(&vmbus_et)); 197 } 198 199 static int 200 vmbus_et_detach(device_t dev) 201 { 202 return (et_deregister(&vmbus_et)); 203 } 204