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/mipsregs.h>
  24 #include <asm/mmu_context.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 unsigned long GUESTID_MASK;
  34 EXPORT_SYMBOL_GPL(GUESTID_MASK);
  35 unsigned long GUESTID_FIRST_VERSION;
  36 EXPORT_SYMBOL_GPL(GUESTID_FIRST_VERSION);
  37 unsigned long GUESTID_VERSION_MASK;
  38 EXPORT_SYMBOL_GPL(GUESTID_VERSION_MASK);
  39
  40 static u32 kvm_mips_get_root_asid(struct kvm_vcpu *vcpu)
  41 {
  42         struct mm_struct *gpa_mm = &vcpu->kvm->arch.gpa_mm;
  43
  44         if (cpu_has_guestid)
  45                 return 0;
  46         else
  47                 return cpu_asid(smp_processor_id(), gpa_mm);
  48 }
  49
  50 static int _kvm_mips_host_tlb_inv(unsigned long entryhi)
  51 {
  52         int idx;
  53
  54         write_c0_entryhi(entryhi);
  55         mtc0_tlbw_hazard();
  56
  57         tlb_probe();
  58         tlb_probe_hazard();
  59         idx = read_c0_index();
  60
  61         if (idx >= current_cpu_data.tlbsize)
  62                 BUG();
  63
  64         if (idx >= 0) {
  65                 write_c0_entryhi(UNIQUE_ENTRYHI(idx));
  66                 write_c0_entrylo0(0);
  67                 write_c0_entrylo1(0);
  68                 mtc0_tlbw_hazard();
  69
  70                 tlb_write_indexed();
  71                 tlbw_use_hazard();
  72         }
  73
  74         return idx;
  75 }
  76
  77 /* GuestID management */
  78
  79 /**
  80  * clear_root_gid() - Set GuestCtl1.RID for normal root operation.
  81  */
  82 static inline void clear_root_gid(void)
  83 {
  84         if (cpu_has_guestid) {
  85                 clear_c0_guestctl1(MIPS_GCTL1_RID);
  86                 mtc0_tlbw_hazard();
  87         }
  88 }
  89
  90 /**
  91  * set_root_gid_to_guest_gid() - Set GuestCtl1.RID to match GuestCtl1.ID.
  92  *
  93  * Sets the root GuestID to match the current guest GuestID, for TLB operation
  94  * on the GPA->RPA mappings in the root TLB.
  95  *
  96  * The caller must be sure to disable HTW while the root GID is set, and
  97  * possibly longer if TLB registers are modified.
  98  */
  99 static inline void set_root_gid_to_guest_gid(void)
 100 {
 101         unsigned int guestctl1;
 102
 103         if (cpu_has_guestid) {
 104                 back_to_back_c0_hazard();
 105                 guestctl1 = read_c0_guestctl1();
 106                 guestctl1 = (guestctl1 & ~MIPS_GCTL1_RID) |
 107                         ((guestctl1 & MIPS_GCTL1_ID) >> MIPS_GCTL1_ID_SHIFT)
 108                                                      << MIPS_GCTL1_RID_SHIFT;
 109                 write_c0_guestctl1(guestctl1);
 110                 mtc0_tlbw_hazard();
 111         }
 112 }
 113
 114 int kvm_vz_host_tlb_inv(struct kvm_vcpu *vcpu, unsigned long va)
 115 {
 116         int idx;
 117         unsigned long flags, old_entryhi;
 118
 119         local_irq_save(flags);
 120         htw_stop();
 121
 122         /* Set root GuestID for root probe and write of guest TLB entry */
 123         set_root_gid_to_guest_gid();
 124
 125         old_entryhi = read_c0_entryhi();
 126
 127         idx = _kvm_mips_host_tlb_inv((va & VPN2_MASK) |
 128                                      kvm_mips_get_root_asid(vcpu));
 129
 130         write_c0_entryhi(old_entryhi);
 131         clear_root_gid();
 132         mtc0_tlbw_hazard();
 133
 134         htw_start();
 135         local_irq_restore(flags);
 136
 137         /*
 138          * We don't want to get reserved instruction exceptions for missing tlb
 139          * entries.
 140          */
 141         if (cpu_has_vtag_icache)
 142                 flush_icache_all();
 143
 144         if (idx > 0)
 145                 kvm_debug("%s: Invalidated root entryhi %#lx @ idx %d\n",
 146                           __func__, (va & VPN2_MASK) |
 147                                     kvm_mips_get_root_asid(vcpu), idx);
 148
 149         return 0;
 150 }
 151 EXPORT_SYMBOL_GPL(kvm_vz_host_tlb_inv);
 152
 153 /**
 154  * kvm_vz_guest_tlb_lookup() - Lookup a guest VZ TLB mapping.
 155  * @vcpu:       KVM VCPU pointer.
 156  * @gpa:        Guest virtual address in a TLB mapped guest segment.
 157  * @gpa:        Ponter to output guest physical address it maps to.
 158  *
 159  * Converts a guest virtual address in a guest TLB mapped segment to a guest
 160  * physical address, by probing the guest TLB.
 161  *
 162  * Returns:     0 if guest TLB mapping exists for @gva. *@gpa will have been
 163  *              written.
 164  *              -EFAULT if no guest TLB mapping exists for @gva. *@gpa may not
 165  *              have been written.
 166  */
 167 int kvm_vz_guest_tlb_lookup(struct kvm_vcpu *vcpu, unsigned long gva,
 168                             unsigned long *gpa)
 169 {
 170         unsigned long o_entryhi, o_entrylo[2], o_pagemask;
 171         unsigned int o_index;
 172         unsigned long entrylo[2], pagemask, pagemaskbit, pa;
 173         unsigned long flags;
 174         int index;
 175
 176         /* Probe the guest TLB for a mapping */
 177         local_irq_save(flags);
 178         /* Set root GuestID for root probe of guest TLB entry */
 179         htw_stop();
 180         set_root_gid_to_guest_gid();
 181
 182         o_entryhi = read_gc0_entryhi();
 183         o_index = read_gc0_index();
 184
 185         write_gc0_entryhi((o_entryhi & 0x3ff) | (gva & ~0xfffl));
 186         mtc0_tlbw_hazard();
 187         guest_tlb_probe();
 188         tlb_probe_hazard();
 189
 190         index = read_gc0_index();
 191         if (index < 0) {
 192                 /* No match, fail */
 193                 write_gc0_entryhi(o_entryhi);
 194                 write_gc0_index(o_index);
 195
 196                 clear_root_gid();
 197                 htw_start();
 198                 local_irq_restore(flags);
 199                 return -EFAULT;
 200         }
 201
 202         /* Match! read the TLB entry */
 203         o_entrylo[0] = read_gc0_entrylo0();
 204         o_entrylo[1] = read_gc0_entrylo1();
 205         o_pagemask = read_gc0_pagemask();
 206
 207         mtc0_tlbr_hazard();
 208         guest_tlb_read();
 209         tlb_read_hazard();
 210
 211         entrylo[0] = read_gc0_entrylo0();
 212         entrylo[1] = read_gc0_entrylo1();
 213         pagemask = ~read_gc0_pagemask() & ~0x1fffl;
 214
 215         write_gc0_entryhi(o_entryhi);
 216         write_gc0_index(o_index);
 217         write_gc0_entrylo0(o_entrylo[0]);
 218         write_gc0_entrylo1(o_entrylo[1]);
 219         write_gc0_pagemask(o_pagemask);
 220
 221         clear_root_gid();
 222         htw_start();
 223         local_irq_restore(flags);
 224
 225         /* Select one of the EntryLo values and interpret the GPA */
 226         pagemaskbit = (pagemask ^ (pagemask & (pagemask - 1))) >> 1;
 227         pa = entrylo[!!(gva & pagemaskbit)];
 228
 229         /*
 230          * TLB entry may have become invalid since TLB probe if physical FTLB
 231          * entries are shared between threads (e.g. I6400).
 232          */
 233         if (!(pa & ENTRYLO_V))
 234                 return -EFAULT;
 235
 236         /*
 237          * Note, this doesn't take guest MIPS32 XPA into account, where PFN is
 238          * split with XI/RI in the middle.
 239          */
 240         pa = (pa << 6) & ~0xfffl;
 241         pa |= gva & ~(pagemask | pagemaskbit);
 242
 243         *gpa = pa;
 244         return 0;
 245 }
 246 EXPORT_SYMBOL_GPL(kvm_vz_guest_tlb_lookup);
 247
 248 /**
 249  * kvm_vz_local_flush_roottlb_all_guests() - Flush all root TLB entries for
 250  * guests.
 251  *
 252  * Invalidate all entries in root tlb which are GPA mappings.
 253  */
 254 void kvm_vz_local_flush_roottlb_all_guests(void)
 255 {
 256         unsigned long flags;
 257         unsigned long old_entryhi, old_pagemask, old_guestctl1;
 258         int entry;
 259
 260         if (WARN_ON(!cpu_has_guestid))
 261                 return;
 262
 263         local_irq_save(flags);
 264         htw_stop();
 265
 266         /* TLBR may clobber EntryHi.ASID, PageMask, and GuestCtl1.RID */
 267         old_entryhi = read_c0_entryhi();
 268         old_pagemask = read_c0_pagemask();
 269         old_guestctl1 = read_c0_guestctl1();
 270
 271         /*
 272          * Invalidate guest entries in root TLB while leaving root entries
 273          * intact when possible.
 274          */
 275         for (entry = 0; entry < current_cpu_data.tlbsize; entry++) {
 276                 write_c0_index(entry);
 277                 mtc0_tlbw_hazard();
 278                 tlb_read();
 279                 tlb_read_hazard();
 280
 281                 /* Don't invalidate non-guest (RVA) mappings in the root TLB */
 282                 if (!(read_c0_guestctl1() & MIPS_GCTL1_RID))
 283                         continue;
 284
 285                 /* Make sure all entries differ. */
 286                 write_c0_entryhi(UNIQUE_ENTRYHI(entry));
 287                 write_c0_entrylo0(0);
 288                 write_c0_entrylo1(0);
 289                 write_c0_guestctl1(0);
 290                 mtc0_tlbw_hazard();
 291                 tlb_write_indexed();
 292         }
 293
 294         write_c0_entryhi(old_entryhi);
 295         write_c0_pagemask(old_pagemask);
 296         write_c0_guestctl1(old_guestctl1);
 297         tlbw_use_hazard();
 298
 299         htw_start();
 300         local_irq_restore(flags);
 301 }
 302 EXPORT_SYMBOL_GPL(kvm_vz_local_flush_roottlb_all_guests);
 303
 304 /**
 305  * kvm_vz_local_flush_guesttlb_all() - Flush all guest TLB entries.
 306  *
 307  * Invalidate all entries in guest tlb irrespective of guestid.
 308  */
 309 void kvm_vz_local_flush_guesttlb_all(void)
 310 {
 311         unsigned long flags;
 312         unsigned long old_index;
 313         unsigned long old_entryhi;
 314         unsigned long old_entrylo[2];
 315         unsigned long old_pagemask;
 316         int entry;
 317         u64 cvmmemctl2 = 0;
 318
 319         local_irq_save(flags);
 320
 321         /* Preserve all clobbered guest registers */
 322         old_index = read_gc0_index();
 323         old_entryhi = read_gc0_entryhi();
 324         old_entrylo[0] = read_gc0_entrylo0();
 325         old_entrylo[1] = read_gc0_entrylo1();
 326         old_pagemask = read_gc0_pagemask();
 327
 328         switch (current_cpu_type()) {
 329         case CPU_CAVIUM_OCTEON3:
 330                 /* Inhibit machine check due to multiple matching TLB entries */
 331                 cvmmemctl2 = read_c0_cvmmemctl2();
 332                 cvmmemctl2 |= CVMMEMCTL2_INHIBITTS;
 333                 write_c0_cvmmemctl2(cvmmemctl2);
 334                 break;
 335         }
 336
 337         /* Invalidate guest entries in guest TLB */
 338         write_gc0_entrylo0(0);
 339         write_gc0_entrylo1(0);
 340         write_gc0_pagemask(0);
 341         for (entry = 0; entry < current_cpu_data.guest.tlbsize; entry++) {
 342                 /* Make sure all entries differ. */
 343                 write_gc0_index(entry);
 344                 write_gc0_entryhi(UNIQUE_GUEST_ENTRYHI(entry));
 345                 mtc0_tlbw_hazard();
 346                 guest_tlb_write_indexed();
 347         }
 348
 349         if (cvmmemctl2) {
 350                 cvmmemctl2 &= ~CVMMEMCTL2_INHIBITTS;
 351                 write_c0_cvmmemctl2(cvmmemctl2);
 352         }
 353
 354         write_gc0_index(old_index);
 355         write_gc0_entryhi(old_entryhi);
 356         write_gc0_entrylo0(old_entrylo[0]);
 357         write_gc0_entrylo1(old_entrylo[1]);
 358         write_gc0_pagemask(old_pagemask);
 359         tlbw_use_hazard();
 360
 361         local_irq_restore(flags);
 362 }
 363 EXPORT_SYMBOL_GPL(kvm_vz_local_flush_guesttlb_all);
 364
 365 /**
 366  * kvm_vz_save_guesttlb() - Save a range of guest TLB entries.
 367  * @buf:        Buffer to write TLB entries into.
 368  * @index:      Start index.
 369  * @count:      Number of entries to save.
 370  *
 371  * Save a range of guest TLB entries. The caller must ensure interrupts are
 372  * disabled.
 373  */
 374 void kvm_vz_save_guesttlb(struct kvm_mips_tlb *buf, unsigned int index,
 375                           unsigned int count)
 376 {
 377         unsigned int end = index + count;
 378         unsigned long old_entryhi, old_entrylo0, old_entrylo1, old_pagemask;
 379         unsigned int guestctl1 = 0;
 380         int old_index, i;
 381
 382         /* Save registers we're about to clobber */
 383         old_index = read_gc0_index();
 384         old_entryhi = read_gc0_entryhi();
 385         old_entrylo0 = read_gc0_entrylo0();
 386         old_entrylo1 = read_gc0_entrylo1();
 387         old_pagemask = read_gc0_pagemask();
 388
 389         /* Set root GuestID for root probe */
 390         htw_stop();
 391         set_root_gid_to_guest_gid();
 392         if (cpu_has_guestid)
 393                 guestctl1 = read_c0_guestctl1();
 394
 395         /* Read each entry from guest TLB */
 396         for (i = index; i < end; ++i, ++buf) {
 397                 write_gc0_index(i);
 398
 399                 mtc0_tlbr_hazard();
 400                 guest_tlb_read();
 401                 tlb_read_hazard();
 402
 403                 if (cpu_has_guestid &&
 404                     (read_c0_guestctl1() ^ guestctl1) & MIPS_GCTL1_RID) {
 405                         /* Entry invalid or belongs to another guest */
 406                         buf->tlb_hi = UNIQUE_GUEST_ENTRYHI(i);
 407                         buf->tlb_lo[0] = 0;
 408                         buf->tlb_lo[1] = 0;
 409                         buf->tlb_mask = 0;
 410                 } else {
 411                         /* Entry belongs to the right guest */
 412                         buf->tlb_hi = read_gc0_entryhi();
 413                         buf->tlb_lo[0] = read_gc0_entrylo0();
 414                         buf->tlb_lo[1] = read_gc0_entrylo1();
 415                         buf->tlb_mask = read_gc0_pagemask();
 416                 }
 417         }
 418
 419         /* Clear root GuestID again */
 420         clear_root_gid();
 421         htw_start();
 422
 423         /* Restore clobbered registers */
 424         write_gc0_index(old_index);
 425         write_gc0_entryhi(old_entryhi);
 426         write_gc0_entrylo0(old_entrylo0);
 427         write_gc0_entrylo1(old_entrylo1);
 428         write_gc0_pagemask(old_pagemask);
 429
 430         tlbw_use_hazard();
 431 }
 432 EXPORT_SYMBOL_GPL(kvm_vz_save_guesttlb);
 433
 434 /**
 435  * kvm_vz_load_guesttlb() - Save a range of guest TLB entries.
 436  * @buf:        Buffer to read TLB entries from.
 437  * @index:      Start index.
 438  * @count:      Number of entries to load.
 439  *
 440  * Load a range of guest TLB entries. The caller must ensure interrupts are
 441  * disabled.
 442  */
 443 void kvm_vz_load_guesttlb(const struct kvm_mips_tlb *buf, unsigned int index,
 444                           unsigned int count)
 445 {
 446         unsigned int end = index + count;
 447         unsigned long old_entryhi, old_entrylo0, old_entrylo1, old_pagemask;
 448         int old_index, i;
 449
 450         /* Save registers we're about to clobber */
 451         old_index = read_gc0_index();
 452         old_entryhi = read_gc0_entryhi();
 453         old_entrylo0 = read_gc0_entrylo0();
 454         old_entrylo1 = read_gc0_entrylo1();
 455         old_pagemask = read_gc0_pagemask();
 456
 457         /* Set root GuestID for root probe */
 458         htw_stop();
 459         set_root_gid_to_guest_gid();
 460
 461         /* Write each entry to guest TLB */
 462         for (i = index; i < end; ++i, ++buf) {
 463                 write_gc0_index(i);
 464                 write_gc0_entryhi(buf->tlb_hi);
 465                 write_gc0_entrylo0(buf->tlb_lo[0]);
 466                 write_gc0_entrylo1(buf->tlb_lo[1]);
 467                 write_gc0_pagemask(buf->tlb_mask);
 468
 469                 mtc0_tlbw_hazard();
 470                 guest_tlb_write_indexed();
 471         }
 472
 473         /* Clear root GuestID again */
 474         clear_root_gid();
 475         htw_start();
 476
 477         /* Restore clobbered registers */
 478         write_gc0_index(old_index);
 479         write_gc0_entryhi(old_entryhi);
 480         write_gc0_entrylo0(old_entrylo0);
 481         write_gc0_entrylo1(old_entrylo1);
 482         write_gc0_pagemask(old_pagemask);
 483
 484         tlbw_use_hazard();
 485 }
 486 EXPORT_SYMBOL_GPL(kvm_vz_load_guesttlb);
 487
 488 #ifdef CONFIG_CPU_LOONGSON64
 489 void kvm_loongson_clear_guest_vtlb(void)
 490 {
 491         int idx = read_gc0_index();
 492
 493         /* Set root GuestID for root probe and write of guest TLB entry */
 494         set_root_gid_to_guest_gid();
 495
 496         write_gc0_index(0);
 497         guest_tlbinvf();
 498         write_gc0_index(idx);
 499
 500         clear_root_gid();
 501         set_c0_diag(LOONGSON_DIAG_ITLB | LOONGSON_DIAG_DTLB);
 502 }
 503 EXPORT_SYMBOL_GPL(kvm_loongson_clear_guest_vtlb);
 504
 505 void kvm_loongson_clear_guest_ftlb(void)
 506 {
 507         int i;
 508         int idx = read_gc0_index();
 509
 510         /* Set root GuestID for root probe and write of guest TLB entry */
 511         set_root_gid_to_guest_gid();
 512
 513         for (i = current_cpu_data.tlbsizevtlb;
 514              i < (current_cpu_data.tlbsizevtlb +
 515                      current_cpu_data.tlbsizeftlbsets);
 516              i++) {
 517                 write_gc0_index(i);
 518                 guest_tlbinvf();
 519         }
 520         write_gc0_index(idx);
 521
 522         clear_root_gid();
 523         set_c0_diag(LOONGSON_DIAG_ITLB | LOONGSON_DIAG_DTLB);
 524 }
 525 EXPORT_SYMBOL_GPL(kvm_loongson_clear_guest_ftlb);
 526 #endif