linux/arch/mips/kvm/tlb.c
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   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
  36atomic_t kvm_mips_instance;
  37EXPORT_SYMBOL_GPL(kvm_mips_instance);
  38
  39static 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
  47static 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
  55inline 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
  62void 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}
  75EXPORT_SYMBOL_GPL(kvm_mips_dump_host_tlbs);
  76
  77void 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}
 105EXPORT_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 */
 109int 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}
 169EXPORT_SYMBOL_GPL(kvm_mips_host_tlb_write);
 170
 171int 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}
 208EXPORT_SYMBOL_GPL(kvm_mips_handle_commpage_tlb_fault);
 209
 210int 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}
 229EXPORT_SYMBOL_GPL(kvm_mips_guest_tlb_lookup);
 230
 231int 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}
 264EXPORT_SYMBOL_GPL(kvm_mips_host_tlb_lookup);
 265
 266int 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}
 306EXPORT_SYMBOL_GPL(kvm_mips_host_tlb_inv);
 307
 308void 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}
 355EXPORT_SYMBOL_GPL(kvm_mips_flush_host_tlb);
 356
 357void 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}
 384EXPORT_SYMBOL_GPL(kvm_local_flush_tlb_all);
 385