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_multi(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;
  62         unsigned long flags;
  63
  64         trace_hyperv_mmu_flush_tlb_multi(cpus, info);
  65
  66         if (!hv_hypercall_pg)
  67                 goto do_native;
  68
  69         local_irq_save(flags);
  70
  71         flush_pcpu = (struct hv_tlb_flush **)
  72                      this_cpu_ptr(hyperv_pcpu_input_arg);
  73
  74         flush = *flush_pcpu;
  75
  76         if (unlikely(!flush)) {
  77                 local_irq_restore(flags);
  78                 goto do_native;
  79         }
  80
  81         if (info->mm) {
  82                 /*
  83                  * AddressSpace argument must match the CR3 with PCID bits
  84                  * stripped out.
  85                  */
  86                 flush->address_space = virt_to_phys(info->mm->pgd);
  87                 flush->address_space &= CR3_ADDR_MASK;
  88                 flush->flags = 0;
  89         } else {
  90                 flush->address_space = 0;
  91                 flush->flags = HV_FLUSH_ALL_VIRTUAL_ADDRESS_SPACES;
  92         }
  93
  94         flush->processor_mask = 0;
  95         if (cpumask_equal(cpus, cpu_present_mask)) {
  96                 flush->flags |= HV_FLUSH_ALL_PROCESSORS;
  97         } else {
  98                 /*
  99                  * From the supplied CPU set we need to figure out if we can get
 100                  * away with cheaper HVCALL_FLUSH_VIRTUAL_ADDRESS_{LIST,SPACE}
 101                  * hypercalls. This is possible when the highest VP number in
 102                  * the set is < 64. As VP numbers are usually in ascending order
 103                  * and match Linux CPU ids, here is an optimization: we check
 104                  * the VP number for the highest bit in the supplied set first
 105                  * so we can quickly find out if using *_EX hypercalls is a
 106                  * must. We will also check all VP numbers when walking the
 107                  * supplied CPU set to remain correct in all cases.
 108                  */
 109                 cpu = cpumask_last(cpus);
 110
 111                 if (cpu < nr_cpumask_bits && hv_cpu_number_to_vp_number(cpu) >= 64)
 112                         goto do_ex_hypercall;
 113
 114                 for_each_cpu(cpu, cpus) {
 115                         vcpu = hv_cpu_number_to_vp_number(cpu);
 116                         if (vcpu == VP_INVAL) {
 117                                 local_irq_restore(flags);
 118                                 goto do_native;
 119                         }
 120
 121                         if (vcpu >= 64)
 122                                 goto do_ex_hypercall;
 123
 124                         __set_bit(vcpu, (unsigned long *)
 125                                   &flush->processor_mask);
 126                 }
 127
 128                 /* nothing to flush if 'processor_mask' ends up being empty */
 129                 if (!flush->processor_mask) {
 130                         local_irq_restore(flags);
 131                         return;
 132                 }
 133         }
 134
 135         /*
 136          * We can flush not more than max_gvas with one hypercall. Flush the
 137          * whole address space if we were asked to do more.
 138          */
 139         max_gvas = (PAGE_SIZE - sizeof(*flush)) / sizeof(flush->gva_list[0]);
 140
 141         if (info->end == TLB_FLUSH_ALL) {
 142                 flush->flags |= HV_FLUSH_NON_GLOBAL_MAPPINGS_ONLY;
 143                 status = hv_do_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE,
 144                                          flush, NULL);
 145         } else if (info->end &&
 146                    ((info->end - info->start)/HV_TLB_FLUSH_UNIT) > max_gvas) {
 147                 status = hv_do_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE,
 148                                          flush, NULL);
 149         } else {
 150                 gva_n = fill_gva_list(flush->gva_list, 0,
 151                                       info->start, info->end);
 152                 status = hv_do_rep_hypercall(HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST,
 153                                              gva_n, 0, flush, NULL);
 154         }
 155         goto check_status;
 156
 157 do_ex_hypercall:
 158         status = hyperv_flush_tlb_others_ex(cpus, info);
 159
 160 check_status:
 161         local_irq_restore(flags);
 162
 163         if (hv_result_success(status))
 164                 return;
 165 do_native:
 166         native_flush_tlb_multi(cpus, info);
 167 }
 168
 169 static u64 hyperv_flush_tlb_others_ex(const struct cpumask *cpus,
 170                                       const struct flush_tlb_info *info)
 171 {
 172         int nr_bank = 0, max_gvas, gva_n;
 173         struct hv_tlb_flush_ex **flush_pcpu;
 174         struct hv_tlb_flush_ex *flush;
 175         u64 status;
 176
 177         if (!(ms_hyperv.hints & HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED))
 178                 return HV_STATUS_INVALID_PARAMETER;
 179
 180         flush_pcpu = (struct hv_tlb_flush_ex **)
 181                      this_cpu_ptr(hyperv_pcpu_input_arg);
 182
 183         flush = *flush_pcpu;
 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(&(flush->hv_vp_set), cpus);
 202         if (nr_bank < 0)
 203                 return HV_STATUS_INVALID_PARAMETER;
 204
 205         /*
 206          * We can flush not more than max_gvas with one hypercall. Flush the
 207          * whole address space if we were asked to do more.
 208          */
 209         max_gvas =
 210                 (PAGE_SIZE - sizeof(*flush) - nr_bank *
 211                  sizeof(flush->hv_vp_set.bank_contents[0])) /
 212                 sizeof(flush->gva_list[0]);
 213
 214         if (info->end == TLB_FLUSH_ALL) {
 215                 flush->flags |= HV_FLUSH_NON_GLOBAL_MAPPINGS_ONLY;
 216                 status = hv_do_rep_hypercall(
 217                         HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX,
 218                         0, nr_bank, flush, NULL);
 219         } else if (info->end &&
 220                    ((info->end - info->start)/HV_TLB_FLUSH_UNIT) > max_gvas) {
 221                 status = hv_do_rep_hypercall(
 222                         HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX,
 223                         0, nr_bank, flush, NULL);
 224         } else {
 225                 gva_n = fill_gva_list(flush->gva_list, nr_bank,
 226                                       info->start, info->end);
 227                 status = hv_do_rep_hypercall(
 228                         HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX,
 229                         gva_n, nr_bank, flush, NULL);
 230         }
 231
 232         return status;
 233 }
 234
 235 void hyperv_setup_mmu_ops(void)
 236 {
 237         if (!(ms_hyperv.hints & HV_X64_REMOTE_TLB_FLUSH_RECOMMENDED))
 238                 return;
 239
 240         pr_info("Using hypercall for remote TLB flush\n");
 241         pv_ops.mmu.flush_tlb_multi = hyperv_flush_tlb_multi;
 242         pv_ops.mmu.tlb_remove_table = tlb_remove_table;
 243 }