arch/mips/kvm/tlb.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * KVM/MIPS TLB handling, this file is part of the Linux host kernel so that
   7  * TLB handlers run from KSEG0
   8  *
   9  * Copyright (C) 2012  MIPS Technologies, Inc.  All rights reserved.
  10  * Authors: Sanjay Lal <sanjayl@kymasys.com>
  11  */
  12
  13 #include <linux/sched.h>
  14 #include <linux/smp.h>
  15 #include <linux/mm.h>
  16 #include <linux/delay.h>
  17 #include <linux/export.h>
  18 #include <linux/kvm_host.h>
  19 #include <linux/srcu.h>
  20
  21 #include <asm/cpu.h>
  22 #include <asm/bootinfo.h>
  23 #include <asm/mmu_context.h>
  24 #include <asm/pgtable.h>
  25 #include <asm/cacheflush.h>
  26 #include <asm/tlb.h>
  27 #include <asm/tlbdebug.h>
  28
  29 #undef CONFIG_MIPS_MT
  30 #include <asm/r4kcache.h>
  31 #define CONFIG_MIPS_MT
  32
  33 #define KVM_GUEST_PC_TLB    0
  34 #define KVM_GUEST_SP_TLB    1
  35
  36 atomic_t kvm_mips_instance;
  37 EXPORT_SYMBOL_GPL(kvm_mips_instance);
  38
  39 static u32 kvm_mips_get_kernel_asid(struct kvm_vcpu *vcpu)
  40 {
  41         int cpu = smp_processor_id();
  42
  43         return vcpu->arch.guest_kernel_asid[cpu] &
  44                         cpu_asid_mask(&cpu_data[cpu]);
  45 }
  46
  47 static u32 kvm_mips_get_user_asid(struct kvm_vcpu *vcpu)
  48 {
  49         int cpu = smp_processor_id();
  50
  51         return vcpu->arch.guest_user_asid[cpu] &
  52                         cpu_asid_mask(&cpu_data[cpu]);
  53 }
  54
  55 inline u32 kvm_mips_get_commpage_asid(struct kvm_vcpu *vcpu)
  56 {
  57         return vcpu->kvm->arch.commpage_tlb;
  58 }
  59
  60 /* Structure defining an tlb entry data set. */
  61
  62 void kvm_mips_dump_host_tlbs(void)
  63 {
  64         unsigned long flags;
  65
  66         local_irq_save(flags);
  67
  68         kvm_info("HOST TLBs:\n");
  69         dump_tlb_regs();
  70         pr_info("\n");
  71         dump_tlb_all();
  72
  73         local_irq_restore(flags);
  74 }
  75 EXPORT_SYMBOL_GPL(kvm_mips_dump_host_tlbs);
  76
  77 void kvm_mips_dump_guest_tlbs(struct kvm_vcpu *vcpu)
  78 {
  79         struct mips_coproc *cop0 = vcpu->arch.cop0;
  80         struct kvm_mips_tlb tlb;
  81         int i;
  82
  83         kvm_info("Guest TLBs:\n");
  84         kvm_info("Guest EntryHi: %#lx\n", kvm_read_c0_guest_entryhi(cop0));
  85
  86         for (i = 0; i < KVM_MIPS_GUEST_TLB_SIZE; i++) {
  87                 tlb = vcpu->arch.guest_tlb[i];
  88                 kvm_info("TLB%c%3d Hi 0x%08lx ",
  89                          (tlb.tlb_lo[0] | tlb.tlb_lo[1]) & ENTRYLO_V
  90                                                         ? ' ' : '*',
  91                          i, tlb.tlb_hi);
  92                 kvm_info("Lo0=0x%09llx %c%c attr %lx ",
  93                          (u64) mips3_tlbpfn_to_paddr(tlb.tlb_lo[0]),
  94                          (tlb.tlb_lo[0] & ENTRYLO_D) ? 'D' : ' ',
  95                          (tlb.tlb_lo[0] & ENTRYLO_G) ? 'G' : ' ',
  96                          (tlb.tlb_lo[0] & ENTRYLO_C) >> ENTRYLO_C_SHIFT);
  97                 kvm_info("Lo1=0x%09llx %c%c attr %lx sz=%lx\n",
  98                          (u64) mips3_tlbpfn_to_paddr(tlb.tlb_lo[1]),
  99                          (tlb.tlb_lo[1] & ENTRYLO_D) ? 'D' : ' ',
 100                          (tlb.tlb_lo[1] & ENTRYLO_G) ? 'G' : ' ',
 101                          (tlb.tlb_lo[1] & ENTRYLO_C) >> ENTRYLO_C_SHIFT,
 102                          tlb.tlb_mask);
 103         }
 104 }
 105 EXPORT_SYMBOL_GPL(kvm_mips_dump_guest_tlbs);
 106
 107 /* XXXKYMA: Must be called with interrupts disabled */
 108 /* set flush_dcache_mask == 0 if no dcache flush required */
 109 int kvm_mips_host_tlb_write(struct kvm_vcpu *vcpu, unsigned long entryhi,
 110                             unsigned long entrylo0, unsigned long entrylo1,
 111                             int flush_dcache_mask)
 112 {
 113         unsigned long flags;
 114         unsigned long old_entryhi;
 115         int idx;
 116
 117         local_irq_save(flags);
 118
 119         old_entryhi = read_c0_entryhi();
 120         write_c0_entryhi(entryhi);
 121         mtc0_tlbw_hazard();
 122
 123         tlb_probe();
 124         tlb_probe_hazard();
 125         idx = read_c0_index();
 126
 127         if (idx > current_cpu_data.tlbsize) {
 128                 kvm_err("%s: Invalid Index: %d\n", __func__, idx);
 129                 kvm_mips_dump_host_tlbs();
 130                 local_irq_restore(flags);
 131                 return -1;
 132         }
 133
 134         write_c0_entrylo0(entrylo0);
 135         write_c0_entrylo1(entrylo1);
 136         mtc0_tlbw_hazard();
 137
 138         if (idx < 0)
 139                 tlb_write_random();
 140         else
 141                 tlb_write_indexed();
 142         tlbw_use_hazard();
 143
 144         kvm_debug("@ %#lx idx: %2d [entryhi(R): %#lx] entrylo0(R): 0x%08lx, entrylo1(R): 0x%08lx\n",
 145                   vcpu->arch.pc, idx, read_c0_entryhi(),
 146                   read_c0_entrylo0(), read_c0_entrylo1());
 147
 148         /* Flush D-cache */
 149         if (flush_dcache_mask) {
 150                 if (entrylo0 & ENTRYLO_V) {
 151                         ++vcpu->stat.flush_dcache_exits;
 152                         flush_data_cache_page((entryhi & VPN2_MASK) &
 153                                               ~flush_dcache_mask);
 154                 }
 155                 if (entrylo1 & ENTRYLO_V) {
 156                         ++vcpu->stat.flush_dcache_exits;
 157                         flush_data_cache_page(((entryhi & VPN2_MASK) &
 158                                                ~flush_dcache_mask) |
 159                                               (0x1 << PAGE_SHIFT));
 160                 }
 161         }
 162
 163         /* Restore old ASID */
 164         write_c0_entryhi(old_entryhi);
 165         mtc0_tlbw_hazard();
 166         local_irq_restore(flags);
 167         return 0;
 168 }
 169 EXPORT_SYMBOL_GPL(kvm_mips_host_tlb_write);
 170
 171 int kvm_mips_handle_commpage_tlb_fault(unsigned long badvaddr,
 172         struct kvm_vcpu *vcpu)
 173 {
 174         kvm_pfn_t pfn;
 175         unsigned long flags, old_entryhi = 0, vaddr = 0;
 176         unsigned long entrylo[2] = { 0, 0 };
 177         unsigned int pair_idx;
 178
 179         pfn = PFN_DOWN(virt_to_phys(vcpu->arch.kseg0_commpage));
 180         pair_idx = (badvaddr >> PAGE_SHIFT) & 1;
 181         entrylo[pair_idx] = mips3_paddr_to_tlbpfn(pfn << PAGE_SHIFT) |
 182                 ((_page_cachable_default >> _CACHE_SHIFT) << ENTRYLO_C_SHIFT) |
 183                 ENTRYLO_D | ENTRYLO_V;
 184
 185         local_irq_save(flags);
 186
 187         old_entryhi = read_c0_entryhi();
 188         vaddr = badvaddr & (PAGE_MASK << 1);
 189         write_c0_entryhi(vaddr | kvm_mips_get_kernel_asid(vcpu));
 190         write_c0_entrylo0(entrylo[0]);
 191         write_c0_entrylo1(entrylo[1]);
 192         write_c0_index(kvm_mips_get_commpage_asid(vcpu));
 193         mtc0_tlbw_hazard();
 194         tlb_write_indexed();
 195         tlbw_use_hazard();
 196
 197         kvm_debug("@ %#lx idx: %2d [entryhi(R): %#lx] entrylo0 (R): 0x%08lx, entrylo1(R): 0x%08lx\n",
 198                   vcpu->arch.pc, read_c0_index(), read_c0_entryhi(),
 199                   read_c0_entrylo0(), read_c0_entrylo1());
 200
 201         /* Restore old ASID */
 202         write_c0_entryhi(old_entryhi);
 203         mtc0_tlbw_hazard();
 204         local_irq_restore(flags);
 205
 206         return 0;
 207 }
 208 EXPORT_SYMBOL_GPL(kvm_mips_handle_commpage_tlb_fault);
 209
 210 int kvm_mips_guest_tlb_lookup(struct kvm_vcpu *vcpu, unsigned long entryhi)
 211 {
 212         int i;
 213         int index = -1;
 214         struct kvm_mips_tlb *tlb = vcpu->arch.guest_tlb;
 215
 216         for (i = 0; i < KVM_MIPS_GUEST_TLB_SIZE; i++) {
 217                 if (TLB_HI_VPN2_HIT(tlb[i], entryhi) &&
 218                     TLB_HI_ASID_HIT(tlb[i], entryhi)) {
 219                         index = i;
 220                         break;
 221                 }
 222         }
 223
 224         kvm_debug("%s: entryhi: %#lx, index: %d lo0: %#lx, lo1: %#lx\n",
 225                   __func__, entryhi, index, tlb[i].tlb_lo[0], tlb[i].tlb_lo[1]);
 226
 227         return index;
 228 }
 229 EXPORT_SYMBOL_GPL(kvm_mips_guest_tlb_lookup);
 230
 231 int kvm_mips_host_tlb_lookup(struct kvm_vcpu *vcpu, unsigned long vaddr)
 232 {
 233         unsigned long old_entryhi, flags;
 234         int idx;
 235
 236         local_irq_save(flags);
 237
 238         old_entryhi = read_c0_entryhi();
 239
 240         if (KVM_GUEST_KERNEL_MODE(vcpu))
 241                 write_c0_entryhi((vaddr & VPN2_MASK) |
 242                                  kvm_mips_get_kernel_asid(vcpu));
 243         else {
 244                 write_c0_entryhi((vaddr & VPN2_MASK) |
 245                                  kvm_mips_get_user_asid(vcpu));
 246         }
 247
 248         mtc0_tlbw_hazard();
 249
 250         tlb_probe();
 251         tlb_probe_hazard();
 252         idx = read_c0_index();
 253
 254         /* Restore old ASID */
 255         write_c0_entryhi(old_entryhi);
 256         mtc0_tlbw_hazard();
 257
 258         local_irq_restore(flags);
 259
 260         kvm_debug("Host TLB lookup, %#lx, idx: %2d\n", vaddr, idx);
 261
 262         return idx;
 263 }
 264 EXPORT_SYMBOL_GPL(kvm_mips_host_tlb_lookup);
 265
 266 int kvm_mips_host_tlb_inv(struct kvm_vcpu *vcpu, unsigned long va)
 267 {
 268         int idx;
 269         unsigned long flags, old_entryhi;
 270
 271         local_irq_save(flags);
 272
 273         old_entryhi = read_c0_entryhi();
 274
 275         write_c0_entryhi((va & VPN2_MASK) | kvm_mips_get_user_asid(vcpu));
 276         mtc0_tlbw_hazard();
 277
 278         tlb_probe();
 279         tlb_probe_hazard();
 280         idx = read_c0_index();
 281
 282         if (idx >= current_cpu_data.tlbsize)
 283                 BUG();
 284
 285         if (idx > 0) {
 286                 write_c0_entryhi(UNIQUE_ENTRYHI(idx));
 287                 write_c0_entrylo0(0);
 288                 write_c0_entrylo1(0);
 289                 mtc0_tlbw_hazard();
 290
 291                 tlb_write_indexed();
 292                 tlbw_use_hazard();
 293         }
 294
 295         write_c0_entryhi(old_entryhi);
 296         mtc0_tlbw_hazard();
 297
 298         local_irq_restore(flags);
 299
 300         if (idx > 0)
 301                 kvm_debug("%s: Invalidated entryhi %#lx @ idx %d\n", __func__,
 302                           (va & VPN2_MASK) | kvm_mips_get_user_asid(vcpu), idx);
 303
 304         return 0;
 305 }
 306 EXPORT_SYMBOL_GPL(kvm_mips_host_tlb_inv);
 307
 308 void kvm_mips_flush_host_tlb(int skip_kseg0)
 309 {
 310         unsigned long flags;
 311         unsigned long old_entryhi, entryhi;
 312         unsigned long old_pagemask;
 313         int entry = 0;
 314         int maxentry = current_cpu_data.tlbsize;
 315
 316         local_irq_save(flags);
 317
 318         old_entryhi = read_c0_entryhi();
 319         old_pagemask = read_c0_pagemask();
 320
 321         /* Blast 'em all away. */
 322         for (entry = 0; entry < maxentry; entry++) {
 323                 write_c0_index(entry);
 324
 325                 if (skip_kseg0) {
 326                         mtc0_tlbr_hazard();
 327                         tlb_read();
 328                         tlb_read_hazard();
 329
 330                         entryhi = read_c0_entryhi();
 331
 332                         /* Don't blow away guest kernel entries */
 333                         if (KVM_GUEST_KSEGX(entryhi) == KVM_GUEST_KSEG0)
 334                                 continue;
 335
 336                         write_c0_pagemask(old_pagemask);
 337                 }
 338
 339                 /* Make sure all entries differ. */
 340                 write_c0_entryhi(UNIQUE_ENTRYHI(entry));
 341                 write_c0_entrylo0(0);
 342                 write_c0_entrylo1(0);
 343                 mtc0_tlbw_hazard();
 344
 345                 tlb_write_indexed();
 346                 tlbw_use_hazard();
 347         }
 348
 349         write_c0_entryhi(old_entryhi);
 350         write_c0_pagemask(old_pagemask);
 351         mtc0_tlbw_hazard();
 352
 353         local_irq_restore(flags);
 354 }
 355 EXPORT_SYMBOL_GPL(kvm_mips_flush_host_tlb);
 356
 357 void kvm_local_flush_tlb_all(void)
 358 {
 359         unsigned long flags;
 360         unsigned long old_ctx;
 361         int entry = 0;
 362
 363         local_irq_save(flags);
 364         /* Save old context and create impossible VPN2 value */
 365         old_ctx = read_c0_entryhi();
 366         write_c0_entrylo0(0);
 367         write_c0_entrylo1(0);
 368
 369         /* Blast 'em all away. */
 370         while (entry < current_cpu_data.tlbsize) {
 371                 /* Make sure all entries differ. */
 372                 write_c0_entryhi(UNIQUE_ENTRYHI(entry));
 373                 write_c0_index(entry);
 374                 mtc0_tlbw_hazard();
 375                 tlb_write_indexed();
 376                 tlbw_use_hazard();
 377                 entry++;
 378         }
 379         write_c0_entryhi(old_ctx);
 380         mtc0_tlbw_hazard();
 381
 382         local_irq_restore(flags);
 383 }
 384 EXPORT_SYMBOL_GPL(kvm_local_flush_tlb_all);