1 /*- 2 * Copyright (c) 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 unmodified, this list of conditions, and the following 10 * disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 #include <sys/cdefs.h> 28 __FBSDID("$FreeBSD$"); 29 30 #include <sys/param.h> 31 #include <sys/conf.h> 32 #include <sys/fcntl.h> 33 #include <sys/kernel.h> 34 #include <sys/systm.h> 35 #include <sys/timetc.h> 36 #include <sys/vdso.h> 37 38 #include <machine/cpufunc.h> 39 #include <machine/cputypes.h> 40 #include <machine/md_var.h> 41 #include <machine/specialreg.h> 42 43 #include <vm/vm.h> 44 45 #include <dev/hyperv/include/hyperv.h> 46 #include <dev/hyperv/include/hyperv_busdma.h> 47 #include <dev/hyperv/vmbus/hyperv_machdep.h> 48 #include <dev/hyperv/vmbus/hyperv_reg.h> 49 #include <dev/hyperv/vmbus/hyperv_var.h> 50 51 struct hyperv_reftsc_ctx { 52 struct hyperv_reftsc *tsc_ref; 53 struct hyperv_dma tsc_ref_dma; 54 }; 55 56 static uint32_t hyperv_tsc_vdso_timehands( 57 struct vdso_timehands *, 58 struct timecounter *); 59 60 static d_open_t hyperv_tsc_open; 61 static d_mmap_t hyperv_tsc_mmap; 62 63 static struct timecounter hyperv_tsc_timecounter = { 64 .tc_get_timecount = NULL, /* based on CPU vendor. */ 65 .tc_counter_mask = 0xffffffff, 66 .tc_frequency = HYPERV_TIMER_FREQ, 67 .tc_name = "Hyper-V-TSC", 68 .tc_quality = 3000, 69 .tc_fill_vdso_timehands = hyperv_tsc_vdso_timehands, 70 }; 71 72 static struct cdevsw hyperv_tsc_cdevsw = { 73 .d_version = D_VERSION, 74 .d_open = hyperv_tsc_open, 75 .d_mmap = hyperv_tsc_mmap, 76 .d_name = HYPERV_REFTSC_DEVNAME 77 }; 78 79 static struct hyperv_reftsc_ctx hyperv_ref_tsc; 80 81 uint64_t 82 hypercall_md(volatile void *hc_addr, uint64_t in_val, 83 uint64_t in_paddr, uint64_t out_paddr) 84 { 85 uint64_t status; 86 87 __asm__ __volatile__ ("mov %0, %%r8" : : "r" (out_paddr): "r8"); 88 __asm__ __volatile__ ("call *%3" : "=a" (status) : 89 "c" (in_val), "d" (in_paddr), "m" (hc_addr)); 90 return (status); 91 } 92 93 static int 94 hyperv_tsc_open(struct cdev *dev __unused, int oflags, int devtype __unused, 95 struct thread *td __unused) 96 { 97 98 if (oflags & FWRITE) 99 return (EPERM); 100 return (0); 101 } 102 103 static int 104 hyperv_tsc_mmap(struct cdev *dev __unused, vm_ooffset_t offset, 105 vm_paddr_t *paddr, int nprot __unused, vm_memattr_t *memattr __unused) 106 { 107 108 KASSERT(hyperv_ref_tsc.tsc_ref != NULL, ("reftsc has not been setup")); 109 110 /* 111 * NOTE: 112 * 'nprot' does not contain information interested to us; 113 * WR-open is blocked by d_open. 114 */ 115 116 if (offset != 0) 117 return (EOPNOTSUPP); 118 119 *paddr = hyperv_ref_tsc.tsc_ref_dma.hv_paddr; 120 return (0); 121 } 122 123 static uint32_t 124 hyperv_tsc_vdso_timehands(struct vdso_timehands *vdso_th, 125 struct timecounter *tc __unused) 126 { 127 128 vdso_th->th_algo = VDSO_TH_ALGO_X86_HVTSC; 129 vdso_th->th_x86_shift = 0; 130 vdso_th->th_x86_hpet_idx = 0; 131 bzero(vdso_th->th_res, sizeof(vdso_th->th_res)); 132 return (1); 133 } 134 135 #define HYPERV_TSC_TIMECOUNT(fence) \ 136 static uint64_t \ 137 hyperv_tc64_tsc_##fence(void) \ 138 { \ 139 struct hyperv_reftsc *tsc_ref = hyperv_ref_tsc.tsc_ref; \ 140 uint32_t seq; \ 141 \ 142 while ((seq = atomic_load_acq_int(&tsc_ref->tsc_seq)) != 0) { \ 143 uint64_t disc, ret, tsc; \ 144 uint64_t scale = tsc_ref->tsc_scale; \ 145 int64_t ofs = tsc_ref->tsc_ofs; \ 146 \ 147 fence(); \ 148 tsc = rdtsc(); \ 149 \ 150 /* ret = ((tsc * scale) >> 64) + ofs */ \ 151 __asm__ __volatile__ ("mulq %3" : \ 152 "=d" (ret), "=a" (disc) : \ 153 "a" (tsc), "r" (scale)); \ 154 ret += ofs; \ 155 \ 156 atomic_thread_fence_acq(); \ 157 if (tsc_ref->tsc_seq == seq) \ 158 return (ret); \ 159 \ 160 /* Sequence changed; re-sync. */ \ 161 } \ 162 /* Fallback to the generic timecounter, i.e. rdmsr. */ \ 163 return (rdmsr(MSR_HV_TIME_REF_COUNT)); \ 164 } \ 165 \ 166 static u_int \ 167 hyperv_tsc_timecount_##fence(struct timecounter *tc __unused) \ 168 { \ 169 \ 170 return (hyperv_tc64_tsc_##fence()); \ 171 } \ 172 struct __hack 173 174 HYPERV_TSC_TIMECOUNT(lfence); 175 HYPERV_TSC_TIMECOUNT(mfence); 176 177 static void 178 hyperv_tsc_tcinit(void *dummy __unused) 179 { 180 hyperv_tc64_t tc64 = NULL; 181 uint64_t val, orig; 182 183 if ((hyperv_features & 184 (CPUID_HV_MSR_TIME_REFCNT | CPUID_HV_MSR_REFERENCE_TSC)) != 185 (CPUID_HV_MSR_TIME_REFCNT | CPUID_HV_MSR_REFERENCE_TSC) || 186 (cpu_feature & CPUID_SSE2) == 0) /* SSE2 for mfence/lfence */ 187 return; 188 189 switch (cpu_vendor_id) { 190 case CPU_VENDOR_AMD: 191 hyperv_tsc_timecounter.tc_get_timecount = 192 hyperv_tsc_timecount_mfence; 193 tc64 = hyperv_tc64_tsc_mfence; 194 break; 195 196 case CPU_VENDOR_INTEL: 197 hyperv_tsc_timecounter.tc_get_timecount = 198 hyperv_tsc_timecount_lfence; 199 tc64 = hyperv_tc64_tsc_lfence; 200 break; 201 202 default: 203 /* Unsupport CPU vendors. */ 204 return; 205 } 206 207 hyperv_ref_tsc.tsc_ref = hyperv_dmamem_alloc(NULL, PAGE_SIZE, 0, 208 sizeof(struct hyperv_reftsc), &hyperv_ref_tsc.tsc_ref_dma, 209 BUS_DMA_WAITOK | BUS_DMA_ZERO); 210 if (hyperv_ref_tsc.tsc_ref == NULL) { 211 printf("hyperv: reftsc page allocation failed\n"); 212 return; 213 } 214 215 orig = rdmsr(MSR_HV_REFERENCE_TSC); 216 val = MSR_HV_REFTSC_ENABLE | (orig & MSR_HV_REFTSC_RSVD_MASK) | 217 ((hyperv_ref_tsc.tsc_ref_dma.hv_paddr >> PAGE_SHIFT) << 218 MSR_HV_REFTSC_PGSHIFT); 219 wrmsr(MSR_HV_REFERENCE_TSC, val); 220 221 /* Register "enlightened" timecounter. */ 222 tc_init(&hyperv_tsc_timecounter); 223 224 /* Install 64 bits timecounter method for other modules to use. */ 225 KASSERT(tc64 != NULL, ("tc64 is not set")); 226 hyperv_tc64 = tc64; 227 228 /* Add device for mmap(2). */ 229 make_dev(&hyperv_tsc_cdevsw, 0, UID_ROOT, GID_WHEEL, 0444, 230 HYPERV_REFTSC_DEVNAME); 231 } 232 SYSINIT(hyperv_tsc_init, SI_SUB_DRIVERS, SI_ORDER_FIRST, hyperv_tsc_tcinit, 233 NULL); 234