arch/x86/hyperv/mmu.c

   1 #define pr_fmt(fmt)  "Hyper-V: " fmt
   2
   3 #include <linux/hyperv.h>
   4 #include <linux/log2.h>
   5 #include <linux/slab.h>
   6 #include <linux/types.h>
   7
   8 #include <asm/fpu/api.h>
   9 #include <asm/mshyperv.h>
  10 #include <asm/msr.h>
  11 #include <asm/tlbflush.h>
  12 #include <asm/tlb.h>
  13
  14 #define CREATE_TRACE_POINTS
  15 #include <asm/trace/hyperv.h>
  16
  17 /* Each gva in gva_list encodes up to 4096 pages to flush */
  18 #define HV_TLB_FLUSH_UNIT (4096 * PAGE_SIZE)
  19
  20 static u64 hyperv_flush_tlb_others_ex(const struct cpumask *cpus,
  21                                       const struct flush_tlb_info *info);
  22
  23 /*
  24  * Fills in gva_list starting from offset. Returns the number of items added.
  25  */
  26 static inline int fill_gva_list(u64 gva_list[], int offset,
  27                                 unsigned long start, unsigned long end)
  28 {
  29         int gva_n = offset;
  30         unsigned long cur = start, diff;
  31
  32         do {
  33                 diff = end > cur ? end - cur : 0;
  34
  35                 gva_list[gva_n] = cur & PAGE_MASK;
  36                 /*
  37                  * Lower 12 bits encode the number of additional
  38                  * pages to flush (in addition to the 'cur' page).
  39                  */
  40                 if (diff >= HV_TLB_FLUSH_UNIT) {
  41                         gva_list[gva_n] |= ~PAGE_MASK;
  42                         cur += HV_TLB_FLUSH_UNIT;
  43                 }  else if (diff) {
  44                         gva_list[gva_n] |= (diff - 1) >> PAGE_SHIFT;
  45                         cur = end;
  46                 }
  47
  48                 gva_n++;
  49
  50         } while (cur < end);
  51
  52         return gva_n - offset;
  53 }
  54
  55 static bool cpu_is_lazy(int cpu)
  56 {
  57         return per_cpu(cpu_tlbstate_shared.is_lazy, cpu);
  58 }
  59
  60 static void hyperv_flush_tlb_multi(const struct cpumask *cpus,
  61                                    const struct flush_tlb_info *info)
  62 {
  63         int cpu, vcpu, gva_n, max_gvas;
  64         struct hv_tlb_flush *flush;
  65         u64 status;
  66         unsigned long flags;
  67         bool do_lazy = !info->freed_tables;
  68
  69         trace_hyperv_mmu_flush_tlb_multi(cpus, info);
  70
  71         if (!hv_hypercall_pg)
  72                 goto do_native;
  73
  74         local_irq_save(flags);
  75
  76         flush = *this_cpu_ptr(hyperv_pcpu_input_arg);
  77
  78         if (unlikely(!flush)) {
  79                 local_irq_restore(flags);
  80                 goto do_native;
  81         }
  82
  83         if (info->mm) {
  84                 /*
  85                  * AddressSpace argument must match the CR3 with PCID bits
  86                  * stripped out.
  87                  */
  88                 flush->address_space = virt_to_phys(info->mm->pgd);
  89                 flush->address_space &= CR3_ADDR_MASK;
  90                 flush->flags = 0;
  91         } else {
  92                 flush->address_space = 0;
  93                 flush->flags = HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES;
  94         }
  95
  96         flush->processor_mask = 0;
  97         if (cpumask_equal(cpus, cpu_present_mask)) {
  98                 flush->flags |= HV_FLUSH_ALL_PROCESSORS;
  99         } else {
 100                 /*
 101                  * From the supplied CPU set we need to figure out if we can get
 102                  * away with cheaper HVCALL_FLUSH_VIRTUAL_ADDRESS_{LIST,SPACE}
 103                  * hypercalls. This is possible when the highest VP number in
 104                  * the set is < 64. As VP numbers are usually in ascending order
 105                  * and match Linux CPU ids, here is an optimization: we check
 106                  * the VP number for the highest bit in the supplied set first
 107                  * so we can quickly find out if using *_EX hypercalls is a
 108                  * must. We will also check all VP numbers when walking the
 109                  * supplied CPU set to remain correct in all cases.
 110                  */
 111                 cpu = cpumask_last(cpus);
 112
 113                 if (cpu < nr_cpumask_bits && hv_cpu_number_to_vp_number(cpu) >= 64)
 114                         goto do_ex_hypercall;
 115
 116                 for_each_cpu(cpu, cpus) {
 117                         if (do_lazy && cpu_is_lazy(cpu))
 118                                 continue;
 119                         vcpu = hv_cpu_number_to_vp_number(cpu);
 120                         if (vcpu == VP_INVAL) {
 121                                 local_irq_restore(flags);
 122                                 goto do_native;
 123                         }
 124
 125                         if (vcpu >= 64)
 126                                 goto do_ex_hypercall;
 127
 128                         __set_bit(vcpu, (unsigned long *)
 129                                   &flush->processor_mask);
 130                 }
 131
 132                 /* nothing to flush if 'processor_mask' ends up being empty */
 133                 if (!flush->processor_mask) {
 134                         local_irq_restore(flags);
 135                         return;
 136                 }
 137         }
 138
 139         /*
 140          * We can flush not more than max_gvas with one hypercall. Flush the
 141          * whole address space if we were asked to do more.
 142          */
 143         max_gvas = (PAGE_SIZE - sizeof(*flush)) / sizeof(flush->gva_list[0]);
 144
 145         if (info->end == TLB_FLUSH_ALL) {
 146                 flush->flags |= HV_FLUSH_NON_GLOBAL_MAPPINGS_ONLY;
 147                 status = hv_do_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE,
 148                                          flush, NULL);
 149         } else if (info->end &&
 150                    ((info->end - info->start)/HV_TLB_FLUSH_UNIT) > max_gvas) {
 151                 status = hv_do_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE,
 152                                          flush, NULL);
 153         } else {
 154                 gva_n = fill_gva_list(flush->gva_list, 0,
 155                                       info->start, info->end);
 156                 status = hv_do_rep_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST,
 157                                              gva_n, 0, flush, NULL);
 158         }
 159         goto check_status;
 160
 161 do_ex_hypercall:
 162         status = hyperv_flush_tlb_others_ex(cpus, info);
 163
 164 check_status:
 165         local_irq_restore(flags);
 166
 167         if (hv_result_success(status))
 168                 return;
 169 do_native:
 170         native_flush_tlb_multi(cpus, info);
 171 }
 172
 173 static u64 hyperv_flush_tlb_others_ex(const struct cpumask *cpus,
 174                                       const struct flush_tlb_info *info)
 175 {
 176         int nr_bank = 0, max_gvas, gva_n;
 177         struct hv_tlb_flush_ex *flush;
 178         u64 status;
 179
 180         if (!(ms_hyperv.hints & HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED))
 181                 return HV_STATUS_INVALID_PARAMETER;
 182
 183         flush = *this_cpu_ptr(hyperv_pcpu_input_arg);
 184
 185         if (info->mm) {
 186                 /*
 187                  * AddressSpace argument must match the CR3 with PCID bits
 188                  * stripped out.
 189                  */
 190                 flush->address_space = virt_to_phys(info->mm->pgd);
 191                 flush->address_space &= CR3_ADDR_MASK;
 192                 flush->flags = 0;
 193         } else {
 194                 flush->address_space = 0;
 195                 flush->flags = HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES;
 196         }
 197
 198         flush->hv_vp_set.valid_bank_mask = 0;
 199
 200         flush->hv_vp_set.format = HV_GENERIC_SET_SPARSE_4K;
 201         nr_bank = cpumask_to_vpset_skip(&flush->hv_vp_set, cpus,
 202                         info->freed_tables ? NULL : cpu_is_lazy);
 203         if (nr_bank < 0)
 204                 return HV_STATUS_INVALID_PARAMETER;
 205
 206         /*
 207          * We can flush not more than max_gvas with one hypercall. Flush the
 208          * whole address space if we were asked to do more.
 209          */
 210         max_gvas =
 211                 (PAGE_SIZE - sizeof(*flush) - nr_bank *
 212                  sizeof(flush->hv_vp_set.bank_contents[0])) /
 213                 sizeof(flush->gva_list[0]);
 214
 215         if (info->end == TLB_FLUSH_ALL) {
 216                 flush->flags |= HV_FLUSH_NON_GLOBAL_MAPPINGS_ONLY;
 217                 status = hv_do_rep_hypercall(
 218                         HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX,
 219                         0, nr_bank, flush, NULL);
 220         } else if (info->end &&
 221                    ((info->end - info->start)/HV_TLB_FLUSH_UNIT) > max_gvas) {
 222                 status = hv_do_rep_hypercall(
 223                         HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX,
 224                         0, nr_bank, flush, NULL);
 225         } else {
 226                 gva_n = fill_gva_list(flush->gva_list, nr_bank,
 227                                       info->start, info->end);
 228                 status = hv_do_rep_hypercall(
 229                         HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX,
 230                         gva_n, nr_bank, flush, NULL);
 231         }
 232
 233         return status;
 234 }
 235
 236 void hyperv_setup_mmu_ops(void)
 237 {
 238         if (!(ms_hyperv.hints & HV_X64_REMOTE_TLB_FLUSH_RECOMMENDED))
 239                 return;
 240
 241         pr_info("Using hypercall for remote TLB flush\n");
 242         pv_ops.mmu.flush_tlb_multi = hyperv_flush_tlb_multi;
 243         pv_ops.mmu.tlb_remove_table = tlb_remove_table;
 244 }