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 void hyperv_flush_tlb_others(const struct cpumask *cpus,
  56                                     const struct flush_tlb_info *info)
  57 {
  58         int cpu, vcpu, gva_n, max_gvas;
  59         struct hv_tlb_flush **flush_pcpu;
  60         struct hv_tlb_flush *flush;
  61         u64 status = U64_MAX;
  62         unsigned long flags;
  63
  64         trace_hyperv_mmu_flush_tlb_others(cpus, info);
  65
  66         if (!hv_hypercall_pg)
  67                 goto do_native;
  68
  69         if (cpumask_empty(cpus))
  70                 return;
  71
  72         local_irq_save(flags);
  73
  74         flush_pcpu = (struct hv_tlb_flush **)
  75                      this_cpu_ptr(hyperv_pcpu_input_arg);
  76
  77         flush = *flush_pcpu;
  78
  79         if (unlikely(!flush)) {
  80                 local_irq_restore(flags);
  81                 goto do_native;
  82         }
  83
  84         if (info->mm) {
  85                 /*
  86                  * AddressSpace argument must match the CR3 with PCID bits
  87                  * stripped out.
  88                  */
  89                 flush->address_space = virt_to_phys(info->mm->pgd);
  90                 flush->address_space &= CR3_ADDR_MASK;
  91                 flush->flags = 0;
  92         } else {
  93                 flush->address_space = 0;
  94                 flush->flags = HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES;
  95         }
  96
  97         flush->processor_mask = 0;
  98         if (cpumask_equal(cpus, cpu_present_mask)) {
  99                 flush->flags |= HV_FLUSH_ALL_PROCESSORS;
 100         } else {
 101                 /*
 102                  * From the supplied CPU set we need to figure out if we can get
 103                  * away with cheaper HVCALL_FLUSH_VIRTUAL_ADDRESS_{LIST,SPACE}
 104                  * hypercalls. This is possible when the highest VP number in
 105                  * the set is < 64. As VP numbers are usually in ascending order
 106                  * and match Linux CPU ids, here is an optimization: we check
 107                  * the VP number for the highest bit in the supplied set first
 108                  * so we can quickly find out if using *_EX hypercalls is a
 109                  * must. We will also check all VP numbers when walking the
 110                  * supplied CPU set to remain correct in all cases.
 111                  */
 112                 if (hv_cpu_number_to_vp_number(cpumask_last(cpus)) >= 64)
 113                         goto do_ex_hypercall;
 114
 115                 for_each_cpu(cpu, cpus) {
 116                         vcpu = hv_cpu_number_to_vp_number(cpu);
 117                         if (vcpu == VP_INVAL) {
 118                                 local_irq_restore(flags);
 119                                 goto do_native;
 120                         }
 121
 122                         if (vcpu >= 64)
 123                                 goto do_ex_hypercall;
 124
 125                         __set_bit(vcpu, (unsigned long *)
 126                                   &flush->processor_mask);
 127                 }
 128         }
 129
 130         /*
 131          * We can flush not more than max_gvas with one hypercall. Flush the
 132          * whole address space if we were asked to do more.
 133          */
 134         max_gvas = (PAGE_SIZE - sizeof(*flush)) / sizeof(flush->gva_list[0]);
 135
 136         if (info->end == TLB_FLUSH_ALL) {
 137                 flush->flags |= HV_FLUSH_NON_GLOBAL_MAPPINGS_ONLY;
 138                 status = hv_do_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE,
 139                                          flush, NULL);
 140         } else if (info->end &&
 141                    ((info->end - info->start)/HV_TLB_FLUSH_UNIT) > max_gvas) {
 142                 status = hv_do_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE,
 143                                          flush, NULL);
 144         } else {
 145                 gva_n = fill_gva_list(flush->gva_list, 0,
 146                                       info->start, info->end);
 147                 status = hv_do_rep_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST,
 148                                              gva_n, 0, flush, NULL);
 149         }
 150         goto check_status;
 151
 152 do_ex_hypercall:
 153         status = hyperv_flush_tlb_others_ex(cpus, info);
 154
 155 check_status:
 156         local_irq_restore(flags);
 157
 158         if (!(status & HV_HYPERCALL_RESULT_MASK))
 159                 return;
 160 do_native:
 161         native_flush_tlb_others(cpus, info);
 162 }
 163
 164 static u64 hyperv_flush_tlb_others_ex(const struct cpumask *cpus,
 165                                       const struct flush_tlb_info *info)
 166 {
 167         int nr_bank = 0, max_gvas, gva_n;
 168         struct hv_tlb_flush_ex **flush_pcpu;
 169         struct hv_tlb_flush_ex *flush;
 170         u64 status;
 171
 172         if (!(ms_hyperv.hints & HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED))
 173                 return U64_MAX;
 174
 175         flush_pcpu = (struct hv_tlb_flush_ex **)
 176                      this_cpu_ptr(hyperv_pcpu_input_arg);
 177
 178         flush = *flush_pcpu;
 179
 180         if (info->mm) {
 181                 /*
 182                  * AddressSpace argument must match the CR3 with PCID bits
 183                  * stripped out.
 184                  */
 185                 flush->address_space = virt_to_phys(info->mm->pgd);
 186                 flush->address_space &= CR3_ADDR_MASK;
 187                 flush->flags = 0;
 188         } else {
 189                 flush->address_space = 0;
 190                 flush->flags = HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES;
 191         }
 192
 193         flush->hv_vp_set.valid_bank_mask = 0;
 194
 195         flush->hv_vp_set.format = HV_GENERIC_SET_SPARSE_4K;
 196         nr_bank = cpumask_to_vpset(&(flush->hv_vp_set), cpus);
 197         if (nr_bank < 0)
 198                 return U64_MAX;
 199
 200         /*
 201          * We can flush not more than max_gvas with one hypercall. Flush the
 202          * whole address space if we were asked to do more.
 203          */
 204         max_gvas =
 205                 (PAGE_SIZE - sizeof(*flush) - nr_bank *
 206                  sizeof(flush->hv_vp_set.bank_contents[0])) /
 207                 sizeof(flush->gva_list[0]);
 208
 209         if (info->end == TLB_FLUSH_ALL) {
 210                 flush->flags |= HV_FLUSH_NON_GLOBAL_MAPPINGS_ONLY;
 211                 status = hv_do_rep_hypercall(
 212                         HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX,
 213                         0, nr_bank, flush, NULL);
 214         } else if (info->end &&
 215                    ((info->end - info->start)/HV_TLB_FLUSH_UNIT) > max_gvas) {
 216                 status = hv_do_rep_hypercall(
 217                         HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX,
 218                         0, nr_bank, flush, NULL);
 219         } else {
 220                 gva_n = fill_gva_list(flush->gva_list, nr_bank,
 221                                       info->start, info->end);
 222                 status = hv_do_rep_hypercall(
 223                         HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX,
 224                         gva_n, nr_bank, flush, NULL);
 225         }
 226
 227         return status;
 228 }
 229
 230 void hyperv_setup_mmu_ops(void)
 231 {
 232         if (!(ms_hyperv.hints & HV_X64_REMOTE_TLB_FLUSH_RECOMMENDED))
 233                 return;
 234
 235         pr_info("Using hypercall for remote TLB flush\n");
 236         pv_ops.mmu.flush_tlb_others = hyperv_flush_tlb_others;
 237         pv_ops.mmu.tlb_remove_table = tlb_remove_table;
 238 }