arch/mips/kvm/mmu.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 MMU handling in the KVM module.
   7  *
   8  * Copyright (C) 2012  MIPS Technologies, Inc.  All rights reserved.
   9  * Authors: Sanjay Lal <sanjayl@kymasys.com>
  10  */
  11
  12 #include <linux/kvm_host.h>
  13 #include <asm/mmu_context.h>
  14
  15 static u32 kvm_mips_get_kernel_asid(struct kvm_vcpu *vcpu)
  16 {
  17         int cpu = smp_processor_id();
  18
  19         return vcpu->arch.guest_kernel_asid[cpu] &
  20                         cpu_asid_mask(&cpu_data[cpu]);
  21 }
  22
  23 static u32 kvm_mips_get_user_asid(struct kvm_vcpu *vcpu)
  24 {
  25         int cpu = smp_processor_id();
  26
  27         return vcpu->arch.guest_user_asid[cpu] &
  28                         cpu_asid_mask(&cpu_data[cpu]);
  29 }
  30
  31 static int kvm_mips_map_page(struct kvm *kvm, gfn_t gfn)
  32 {
  33         int srcu_idx, err = 0;
  34         kvm_pfn_t pfn;
  35
  36         if (kvm->arch.guest_pmap[gfn] != KVM_INVALID_PAGE)
  37                 return 0;
  38
  39         srcu_idx = srcu_read_lock(&kvm->srcu);
  40         pfn = gfn_to_pfn(kvm, gfn);
  41
  42         if (is_error_pfn(pfn)) {
  43                 kvm_err("Couldn't get pfn for gfn %#llx!\n", gfn);
  44                 err = -EFAULT;
  45                 goto out;
  46         }
  47
  48         kvm->arch.guest_pmap[gfn] = pfn;
  49 out:
  50         srcu_read_unlock(&kvm->srcu, srcu_idx);
  51         return err;
  52 }
  53
  54 /* Translate guest KSEG0 addresses to Host PA */
  55 unsigned long kvm_mips_translate_guest_kseg0_to_hpa(struct kvm_vcpu *vcpu,
  56                                                     unsigned long gva)
  57 {
  58         gfn_t gfn;
  59         unsigned long offset = gva & ~PAGE_MASK;
  60         struct kvm *kvm = vcpu->kvm;
  61
  62         if (KVM_GUEST_KSEGX(gva) != KVM_GUEST_KSEG0) {
  63                 kvm_err("%s/%p: Invalid gva: %#lx\n", __func__,
  64                         __builtin_return_address(0), gva);
  65                 return KVM_INVALID_PAGE;
  66         }
  67
  68         gfn = (KVM_GUEST_CPHYSADDR(gva) >> PAGE_SHIFT);
  69
  70         if (gfn >= kvm->arch.guest_pmap_npages) {
  71                 kvm_err("%s: Invalid gfn: %#llx, GVA: %#lx\n", __func__, gfn,
  72                         gva);
  73                 return KVM_INVALID_PAGE;
  74         }
  75
  76         if (kvm_mips_map_page(vcpu->kvm, gfn) < 0)
  77                 return KVM_INVALID_ADDR;
  78
  79         return (kvm->arch.guest_pmap[gfn] << PAGE_SHIFT) + offset;
  80 }
  81
  82 /* XXXKYMA: Must be called with interrupts disabled */
  83 int kvm_mips_handle_kseg0_tlb_fault(unsigned long badvaddr,
  84                                     struct kvm_vcpu *vcpu)
  85 {
  86         gfn_t gfn;
  87         kvm_pfn_t pfn0, pfn1;
  88         unsigned long vaddr = 0;
  89         unsigned long entryhi = 0, entrylo0 = 0, entrylo1 = 0;
  90         struct kvm *kvm = vcpu->kvm;
  91         const int flush_dcache_mask = 0;
  92         int ret;
  93
  94         if (KVM_GUEST_KSEGX(badvaddr) != KVM_GUEST_KSEG0) {
  95                 kvm_err("%s: Invalid BadVaddr: %#lx\n", __func__, badvaddr);
  96                 kvm_mips_dump_host_tlbs();
  97                 return -1;
  98         }
  99
 100         gfn = (KVM_GUEST_CPHYSADDR(badvaddr) >> PAGE_SHIFT);
 101         if (gfn >= kvm->arch.guest_pmap_npages) {
 102                 kvm_err("%s: Invalid gfn: %#llx, BadVaddr: %#lx\n", __func__,
 103                         gfn, badvaddr);
 104                 kvm_mips_dump_host_tlbs();
 105                 return -1;
 106         }
 107         vaddr = badvaddr & (PAGE_MASK << 1);
 108
 109         if (kvm_mips_map_page(vcpu->kvm, gfn) < 0)
 110                 return -1;
 111
 112         if (kvm_mips_map_page(vcpu->kvm, gfn ^ 0x1) < 0)
 113                 return -1;
 114
 115         pfn0 = kvm->arch.guest_pmap[gfn & ~0x1];
 116         pfn1 = kvm->arch.guest_pmap[gfn | 0x1];
 117
 118         entrylo0 = mips3_paddr_to_tlbpfn(pfn0 << PAGE_SHIFT) |
 119                 ((_page_cachable_default >> _CACHE_SHIFT) << ENTRYLO_C_SHIFT) |
 120                 ENTRYLO_D | ENTRYLO_V;
 121         entrylo1 = mips3_paddr_to_tlbpfn(pfn1 << PAGE_SHIFT) |
 122                 ((_page_cachable_default >> _CACHE_SHIFT) << ENTRYLO_C_SHIFT) |
 123                 ENTRYLO_D | ENTRYLO_V;
 124
 125         preempt_disable();
 126         entryhi = (vaddr | kvm_mips_get_kernel_asid(vcpu));
 127         ret = kvm_mips_host_tlb_write(vcpu, entryhi, entrylo0, entrylo1,
 128                                       flush_dcache_mask);
 129         preempt_enable();
 130
 131         return ret;
 132 }
 133
 134 int kvm_mips_handle_mapped_seg_tlb_fault(struct kvm_vcpu *vcpu,
 135                                          struct kvm_mips_tlb *tlb)
 136 {
 137         unsigned long entryhi = 0, entrylo0 = 0, entrylo1 = 0;
 138         struct kvm *kvm = vcpu->kvm;
 139         kvm_pfn_t pfn0, pfn1;
 140         int ret;
 141
 142         if ((tlb->tlb_hi & VPN2_MASK) == 0) {
 143                 pfn0 = 0;
 144                 pfn1 = 0;
 145         } else {
 146                 if (kvm_mips_map_page(kvm, mips3_tlbpfn_to_paddr(tlb->tlb_lo[0])
 147                                            >> PAGE_SHIFT) < 0)
 148                         return -1;
 149
 150                 if (kvm_mips_map_page(kvm, mips3_tlbpfn_to_paddr(tlb->tlb_lo[1])
 151                                            >> PAGE_SHIFT) < 0)
 152                         return -1;
 153
 154                 pfn0 = kvm->arch.guest_pmap[
 155                         mips3_tlbpfn_to_paddr(tlb->tlb_lo[0]) >> PAGE_SHIFT];
 156                 pfn1 = kvm->arch.guest_pmap[
 157                         mips3_tlbpfn_to_paddr(tlb->tlb_lo[1]) >> PAGE_SHIFT];
 158         }
 159
 160         /* Get attributes from the Guest TLB */
 161         entrylo0 = mips3_paddr_to_tlbpfn(pfn0 << PAGE_SHIFT) |
 162                 ((_page_cachable_default >> _CACHE_SHIFT) << ENTRYLO_C_SHIFT) |
 163                 (tlb->tlb_lo[0] & ENTRYLO_D) |
 164                 (tlb->tlb_lo[0] & ENTRYLO_V);
 165         entrylo1 = mips3_paddr_to_tlbpfn(pfn1 << PAGE_SHIFT) |
 166                 ((_page_cachable_default >> _CACHE_SHIFT) << ENTRYLO_C_SHIFT) |
 167                 (tlb->tlb_lo[1] & ENTRYLO_D) |
 168                 (tlb->tlb_lo[1] & ENTRYLO_V);
 169
 170         kvm_debug("@ %#lx tlb_lo0: 0x%08lx tlb_lo1: 0x%08lx\n", vcpu->arch.pc,
 171                   tlb->tlb_lo[0], tlb->tlb_lo[1]);
 172
 173         preempt_disable();
 174         entryhi = (tlb->tlb_hi & VPN2_MASK) | (KVM_GUEST_KERNEL_MODE(vcpu) ?
 175                                                kvm_mips_get_kernel_asid(vcpu) :
 176                                                kvm_mips_get_user_asid(vcpu));
 177         ret = kvm_mips_host_tlb_write(vcpu, entryhi, entrylo0, entrylo1,
 178                                       tlb->tlb_mask);
 179         preempt_enable();
 180
 181         return ret;
 182 }
 183
 184 void kvm_get_new_mmu_context(struct mm_struct *mm, unsigned long cpu,
 185                              struct kvm_vcpu *vcpu)
 186 {
 187         unsigned long asid = asid_cache(cpu);
 188
 189         asid += cpu_asid_inc();
 190         if (!(asid & cpu_asid_mask(&cpu_data[cpu]))) {
 191                 if (cpu_has_vtag_icache)
 192                         flush_icache_all();
 193
 194                 kvm_local_flush_tlb_all();      /* start new asid cycle */
 195
 196                 if (!asid)      /* fix version if needed */
 197                         asid = asid_first_version(cpu);
 198         }
 199
 200         cpu_context(cpu, mm) = asid_cache(cpu) = asid;
 201 }
 202
 203 /**
 204  * kvm_mips_migrate_count() - Migrate timer.
 205  * @vcpu:       Virtual CPU.
 206  *
 207  * Migrate CP0_Count hrtimer to the current CPU by cancelling and restarting it
 208  * if it was running prior to being cancelled.
 209  *
 210  * Must be called when the VCPU is migrated to a different CPU to ensure that
 211  * timer expiry during guest execution interrupts the guest and causes the
 212  * interrupt to be delivered in a timely manner.
 213  */
 214 static void kvm_mips_migrate_count(struct kvm_vcpu *vcpu)
 215 {
 216         if (hrtimer_cancel(&vcpu->arch.comparecount_timer))
 217                 hrtimer_restart(&vcpu->arch.comparecount_timer);
 218 }
 219
 220 /* Restore ASID once we are scheduled back after preemption */
 221 void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 222 {
 223         unsigned long asid_mask = cpu_asid_mask(&cpu_data[cpu]);
 224         unsigned long flags;
 225         int newasid = 0;
 226
 227         kvm_debug("%s: vcpu %p, cpu: %d\n", __func__, vcpu, cpu);
 228
 229         /* Allocate new kernel and user ASIDs if needed */
 230
 231         local_irq_save(flags);
 232
 233         if ((vcpu->arch.guest_kernel_asid[cpu] ^ asid_cache(cpu)) &
 234                                                 asid_version_mask(cpu)) {
 235                 kvm_get_new_mmu_context(&vcpu->arch.guest_kernel_mm, cpu, vcpu);
 236                 vcpu->arch.guest_kernel_asid[cpu] =
 237                     vcpu->arch.guest_kernel_mm.context.asid[cpu];
 238                 kvm_get_new_mmu_context(&vcpu->arch.guest_user_mm, cpu, vcpu);
 239                 vcpu->arch.guest_user_asid[cpu] =
 240                     vcpu->arch.guest_user_mm.context.asid[cpu];
 241                 newasid++;
 242
 243                 kvm_debug("[%d]: cpu_context: %#lx\n", cpu,
 244                           cpu_context(cpu, current->mm));
 245                 kvm_debug("[%d]: Allocated new ASID for Guest Kernel: %#x\n",
 246                           cpu, vcpu->arch.guest_kernel_asid[cpu]);
 247                 kvm_debug("[%d]: Allocated new ASID for Guest User: %#x\n", cpu,
 248                           vcpu->arch.guest_user_asid[cpu]);
 249         }
 250
 251         if (vcpu->arch.last_sched_cpu != cpu) {
 252                 kvm_debug("[%d->%d]KVM VCPU[%d] switch\n",
 253                           vcpu->arch.last_sched_cpu, cpu, vcpu->vcpu_id);
 254                 /*
 255                  * Migrate the timer interrupt to the current CPU so that it
 256                  * always interrupts the guest and synchronously triggers a
 257                  * guest timer interrupt.
 258                  */
 259                 kvm_mips_migrate_count(vcpu);
 260         }
 261
 262         if (!newasid) {
 263                 /*
 264                  * If we preempted while the guest was executing, then reload
 265                  * the pre-empted ASID
 266                  */
 267                 if (current->flags & PF_VCPU) {
 268                         write_c0_entryhi(vcpu->arch.
 269                                          preempt_entryhi & asid_mask);
 270                         ehb();
 271                 }
 272         } else {
 273                 /* New ASIDs were allocated for the VM */
 274
 275                 /*
 276                  * Were we in guest context? If so then the pre-empted ASID is
 277                  * no longer valid, we need to set it to what it should be based
 278                  * on the mode of the Guest (Kernel/User)
 279                  */
 280                 if (current->flags & PF_VCPU) {
 281                         if (KVM_GUEST_KERNEL_MODE(vcpu))
 282                                 write_c0_entryhi(vcpu->arch.
 283                                                  guest_kernel_asid[cpu] &
 284                                                  asid_mask);
 285                         else
 286                                 write_c0_entryhi(vcpu->arch.
 287                                                  guest_user_asid[cpu] &
 288                                                  asid_mask);
 289                         ehb();
 290                 }
 291         }
 292
 293         /* restore guest state to registers */
 294         kvm_mips_callbacks->vcpu_set_regs(vcpu);
 295
 296         local_irq_restore(flags);
 297
 298 }
 299
 300 /* ASID can change if another task is scheduled during preemption */
 301 void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 302 {
 303         unsigned long flags;
 304         int cpu;
 305
 306         local_irq_save(flags);
 307
 308         cpu = smp_processor_id();
 309
 310         vcpu->arch.preempt_entryhi = read_c0_entryhi();
 311         vcpu->arch.last_sched_cpu = cpu;
 312
 313         /* save guest state in registers */
 314         kvm_mips_callbacks->vcpu_get_regs(vcpu);
 315
 316         if (((cpu_context(cpu, current->mm) ^ asid_cache(cpu)) &
 317              asid_version_mask(cpu))) {
 318                 kvm_debug("%s: Dropping MMU Context:  %#lx\n", __func__,
 319                           cpu_context(cpu, current->mm));
 320                 drop_mmu_context(current->mm, cpu);
 321         }
 322         write_c0_entryhi(cpu_asid(cpu, current->mm));
 323         ehb();
 324
 325         local_irq_restore(flags);
 326 }
 327
 328 u32 kvm_get_inst(u32 *opc, struct kvm_vcpu *vcpu)
 329 {
 330         struct mips_coproc *cop0 = vcpu->arch.cop0;
 331         unsigned long paddr, flags, vpn2, asid;
 332         unsigned long va = (unsigned long)opc;
 333         u32 inst;
 334         int index;
 335
 336         if (KVM_GUEST_KSEGX(va) < KVM_GUEST_KSEG0 ||
 337             KVM_GUEST_KSEGX(va) == KVM_GUEST_KSEG23) {
 338                 local_irq_save(flags);
 339                 index = kvm_mips_host_tlb_lookup(vcpu, va);
 340                 if (index >= 0) {
 341                         inst = *(opc);
 342                 } else {
 343                         vpn2 = va & VPN2_MASK;
 344                         asid = kvm_read_c0_guest_entryhi(cop0) &
 345                                                 KVM_ENTRYHI_ASID;
 346                         index = kvm_mips_guest_tlb_lookup(vcpu, vpn2 | asid);
 347                         if (index < 0) {
 348                                 kvm_err("%s: get_user_failed for %p, vcpu: %p, ASID: %#lx\n",
 349                                         __func__, opc, vcpu, read_c0_entryhi());
 350                                 kvm_mips_dump_host_tlbs();
 351                                 kvm_mips_dump_guest_tlbs(vcpu);
 352                                 local_irq_restore(flags);
 353                                 return KVM_INVALID_INST;
 354                         }
 355                         kvm_mips_handle_mapped_seg_tlb_fault(vcpu,
 356                                                              &vcpu->arch.
 357                                                              guest_tlb[index]);
 358                         inst = *(opc);
 359                 }
 360                 local_irq_restore(flags);
 361         } else if (KVM_GUEST_KSEGX(va) == KVM_GUEST_KSEG0) {
 362                 paddr = kvm_mips_translate_guest_kseg0_to_hpa(vcpu, va);
 363                 inst = *(u32 *) CKSEG0ADDR(paddr);
 364         } else {
 365                 kvm_err("%s: illegal address: %p\n", __func__, opc);
 366                 return KVM_INVALID_INST;
 367         }
 368
 369         return inst;
 370 }