arch/x86/hyperv/hv_apic.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 /*
   4  * Hyper-V specific APIC code.
   5  *
   6  * Copyright (C) 2018, Microsoft, Inc.
   7  *
   8  * Author : K. Y. Srinivasan <kys@microsoft.com>
   9  *
  10  * This program is free software; you can redistribute it and/or modify it
  11  * under the terms of the GNU General Public License version 2 as published
  12  * by the Free Software Foundation.
  13  *
  14  * This program is distributed in the hope that it will be useful, but
  15  * WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
  17  * NON INFRINGEMENT.  See the GNU General Public License for more
  18  * details.
  19  *
  20  */
  21
  22 #include <linux/types.h>
  23 #include <linux/vmalloc.h>
  24 #include <linux/mm.h>
  25 #include <linux/clockchips.h>
  26 #include <linux/hyperv.h>
  27 #include <linux/slab.h>
  28 #include <linux/cpuhotplug.h>
  29 #include <asm/hypervisor.h>
  30 #include <asm/mshyperv.h>
  31 #include <asm/apic.h>
  32
  33 #include <asm/trace/hyperv.h>
  34
  35 static struct apic orig_apic;
  36
  37 static u64 hv_apic_icr_read(void)
  38 {
  39         u64 reg_val;
  40
  41         rdmsrl(HV_X64_MSR_ICR, reg_val);
  42         return reg_val;
  43 }
  44
  45 static void hv_apic_icr_write(u32 low, u32 id)
  46 {
  47         u64 reg_val;
  48
  49         reg_val = SET_APIC_DEST_FIELD(id);
  50         reg_val = reg_val << 32;
  51         reg_val |= low;
  52
  53         wrmsrl(HV_X64_MSR_ICR, reg_val);
  54 }
  55
  56 static u32 hv_apic_read(u32 reg)
  57 {
  58         u32 reg_val, hi;
  59
  60         switch (reg) {
  61         case APIC_EOI:
  62                 rdmsr(HV_X64_MSR_EOI, reg_val, hi);
  63                 return reg_val;
  64         case APIC_TASKPRI:
  65                 rdmsr(HV_X64_MSR_TPR, reg_val, hi);
  66                 return reg_val;
  67
  68         default:
  69                 return native_apic_mem_read(reg);
  70         }
  71 }
  72
  73 static void hv_apic_write(u32 reg, u32 val)
  74 {
  75         switch (reg) {
  76         case APIC_EOI:
  77                 wrmsr(HV_X64_MSR_EOI, val, 0);
  78                 break;
  79         case APIC_TASKPRI:
  80                 wrmsr(HV_X64_MSR_TPR, val, 0);
  81                 break;
  82         default:
  83                 native_apic_mem_write(reg, val);
  84         }
  85 }
  86
  87 static void hv_apic_eoi_write(u32 reg, u32 val)
  88 {
  89         wrmsr(HV_X64_MSR_EOI, val, 0);
  90 }
  91
  92 /*
  93  * IPI implementation on Hyper-V.
  94  */
  95 static bool __send_ipi_mask_ex(const struct cpumask *mask, int vector)
  96 {
  97         struct hv_send_ipi_ex **arg;
  98         struct hv_send_ipi_ex *ipi_arg;
  99         unsigned long flags;
 100         int nr_bank = 0;
 101         int ret = 1;
 102
 103         if (!(ms_hyperv.hints & HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED))
 104                 return false;
 105
 106         local_irq_save(flags);
 107         arg = (struct hv_send_ipi_ex **)this_cpu_ptr(hyperv_pcpu_input_arg);
 108
 109         ipi_arg = *arg;
 110         if (unlikely(!ipi_arg))
 111                 goto ipi_mask_ex_done;
 112
 113         ipi_arg->vector = vector;
 114         ipi_arg->reserved = 0;
 115         ipi_arg->vp_set.valid_bank_mask = 0;
 116
 117         if (!cpumask_equal(mask, cpu_present_mask)) {
 118                 ipi_arg->vp_set.format = HV_GENERIC_SET_SPARSE_4K;
 119                 nr_bank = cpumask_to_vpset(&(ipi_arg->vp_set), mask);
 120         }
 121         if (nr_bank < 0)
 122                 goto ipi_mask_ex_done;
 123         if (!nr_bank)
 124                 ipi_arg->vp_set.format = HV_GENERIC_SET_ALL;
 125
 126         ret = hv_do_rep_hypercall(HVCALL_SEND_IPI_EX, 0, nr_bank,
 127                               ipi_arg, NULL);
 128
 129 ipi_mask_ex_done:
 130         local_irq_restore(flags);
 131         return ((ret == 0) ? true : false);
 132 }
 133
 134 static bool __send_ipi_mask(const struct cpumask *mask, int vector)
 135 {
 136         int cur_cpu, vcpu;
 137         struct hv_send_ipi ipi_arg;
 138         int ret = 1;
 139
 140         trace_hyperv_send_ipi_mask(mask, vector);
 141
 142         if (cpumask_empty(mask))
 143                 return true;
 144
 145         if (!hv_hypercall_pg)
 146                 return false;
 147
 148         if ((vector < HV_IPI_LOW_VECTOR) || (vector > HV_IPI_HIGH_VECTOR))
 149                 return false;
 150
 151         /*
 152          * From the supplied CPU set we need to figure out if we can get away
 153          * with cheaper HVCALL_SEND_IPI hypercall. This is possible when the
 154          * highest VP number in the set is < 64. As VP numbers are usually in
 155          * ascending order and match Linux CPU ids, here is an optimization:
 156          * we check the VP number for the highest bit in the supplied set first
 157          * so we can quickly find out if using HVCALL_SEND_IPI_EX hypercall is
 158          * a must. We will also check all VP numbers when walking the supplied
 159          * CPU set to remain correct in all cases.
 160          */
 161         if (hv_cpu_number_to_vp_number(cpumask_last(mask)) >= 64)
 162                 goto do_ex_hypercall;
 163
 164         ipi_arg.vector = vector;
 165         ipi_arg.cpu_mask = 0;
 166
 167         for_each_cpu(cur_cpu, mask) {
 168                 vcpu = hv_cpu_number_to_vp_number(cur_cpu);
 169                 if (vcpu == VP_INVAL)
 170                         return false;
 171
 172                 /*
 173                  * This particular version of the IPI hypercall can
 174                  * only target upto 64 CPUs.
 175                  */
 176                 if (vcpu >= 64)
 177                         goto do_ex_hypercall;
 178
 179                 __set_bit(vcpu, (unsigned long *)&ipi_arg.cpu_mask);
 180         }
 181
 182         ret = hv_do_fast_hypercall16(HVCALL_SEND_IPI, ipi_arg.vector,
 183                                      ipi_arg.cpu_mask);
 184         return ((ret == 0) ? true : false);
 185
 186 do_ex_hypercall:
 187         return __send_ipi_mask_ex(mask, vector);
 188 }
 189
 190 static bool __send_ipi_one(int cpu, int vector)
 191 {
 192         struct cpumask mask = CPU_MASK_NONE;
 193
 194         cpumask_set_cpu(cpu, &mask);
 195         return __send_ipi_mask(&mask, vector);
 196 }
 197
 198 static void hv_send_ipi(int cpu, int vector)
 199 {
 200         if (!__send_ipi_one(cpu, vector))
 201                 orig_apic.send_IPI(cpu, vector);
 202 }
 203
 204 static void hv_send_ipi_mask(const struct cpumask *mask, int vector)
 205 {
 206         if (!__send_ipi_mask(mask, vector))
 207                 orig_apic.send_IPI_mask(mask, vector);
 208 }
 209
 210 static void hv_send_ipi_mask_allbutself(const struct cpumask *mask, int vector)
 211 {
 212         unsigned int this_cpu = smp_processor_id();
 213         struct cpumask new_mask;
 214         const struct cpumask *local_mask;
 215
 216         cpumask_copy(&new_mask, mask);
 217         cpumask_clear_cpu(this_cpu, &new_mask);
 218         local_mask = &new_mask;
 219         if (!__send_ipi_mask(local_mask, vector))
 220                 orig_apic.send_IPI_mask_allbutself(mask, vector);
 221 }
 222
 223 static void hv_send_ipi_allbutself(int vector)
 224 {
 225         hv_send_ipi_mask_allbutself(cpu_online_mask, vector);
 226 }
 227
 228 static void hv_send_ipi_all(int vector)
 229 {
 230         if (!__send_ipi_mask(cpu_online_mask, vector))
 231                 orig_apic.send_IPI_all(vector);
 232 }
 233
 234 static void hv_send_ipi_self(int vector)
 235 {
 236         if (!__send_ipi_one(smp_processor_id(), vector))
 237                 orig_apic.send_IPI_self(vector);
 238 }
 239
 240 void __init hv_apic_init(void)
 241 {
 242         if (ms_hyperv.hints & HV_X64_CLUSTER_IPI_RECOMMENDED) {
 243                 pr_info("Hyper-V: Using IPI hypercalls\n");
 244                 /*
 245                  * Set the IPI entry points.
 246                  */
 247                 orig_apic = *apic;
 248
 249                 apic->send_IPI = hv_send_ipi;
 250                 apic->send_IPI_mask = hv_send_ipi_mask;
 251                 apic->send_IPI_mask_allbutself = hv_send_ipi_mask_allbutself;
 252                 apic->send_IPI_allbutself = hv_send_ipi_allbutself;
 253                 apic->send_IPI_all = hv_send_ipi_all;
 254                 apic->send_IPI_self = hv_send_ipi_self;
 255         }
 256
 257         if (ms_hyperv.hints & HV_X64_APIC_ACCESS_RECOMMENDED) {
 258                 pr_info("Hyper-V: Using MSR based APIC access\n");
 259                 apic_set_eoi_write(hv_apic_eoi_write);
 260                 apic->read      = hv_apic_read;
 261                 apic->write     = hv_apic_write;
 262                 apic->icr_write = hv_apic_icr_write;
 263                 apic->icr_read  = hv_apic_icr_read;
 264         }
 265 }