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/highmem.h>
  13 #include <linux/kvm_host.h>
  14 #include <asm/mmu_context.h>
  15
  16 static u32 kvm_mips_get_kernel_asid(struct kvm_vcpu *vcpu)
  17 {
  18         int cpu = smp_processor_id();
  19
  20         return vcpu->arch.guest_kernel_asid[cpu] &
  21                         cpu_asid_mask(&cpu_data[cpu]);
  22 }
  23
  24 static u32 kvm_mips_get_user_asid(struct kvm_vcpu *vcpu)
  25 {
  26         int cpu = smp_processor_id();
  27
  28         return vcpu->arch.guest_user_asid[cpu] &
  29                         cpu_asid_mask(&cpu_data[cpu]);
  30 }
  31
  32 static int kvm_mips_map_page(struct kvm *kvm, gfn_t gfn)
  33 {
  34         int srcu_idx, err = 0;
  35         kvm_pfn_t pfn;
  36
  37         if (kvm->arch.guest_pmap[gfn] != KVM_INVALID_PAGE)
  38                 return 0;
  39
  40         srcu_idx = srcu_read_lock(&kvm->srcu);
  41         pfn = gfn_to_pfn(kvm, gfn);
  42
  43         if (is_error_noslot_pfn(pfn)) {
  44                 kvm_err("Couldn't get pfn for gfn %#llx!\n", gfn);
  45                 err = -EFAULT;
  46                 goto out;
  47         }
  48
  49         kvm->arch.guest_pmap[gfn] = pfn;
  50 out:
  51         srcu_read_unlock(&kvm->srcu, srcu_idx);
  52         return err;
  53 }
  54
  55 /* Translate guest KSEG0 addresses to Host PA */
  56 unsigned long kvm_mips_translate_guest_kseg0_to_hpa(struct kvm_vcpu *vcpu,
  57                                                     unsigned long gva)
  58 {
  59         gfn_t gfn;
  60         unsigned long offset = gva & ~PAGE_MASK;
  61         struct kvm *kvm = vcpu->kvm;
  62
  63         if (KVM_GUEST_KSEGX(gva) != KVM_GUEST_KSEG0) {
  64                 kvm_err("%s/%p: Invalid gva: %#lx\n", __func__,
  65                         __builtin_return_address(0), gva);
  66                 return KVM_INVALID_PAGE;
  67         }
  68
  69         gfn = (KVM_GUEST_CPHYSADDR(gva) >> PAGE_SHIFT);
  70
  71         if (gfn >= kvm->arch.guest_pmap_npages) {
  72                 kvm_err("%s: Invalid gfn: %#llx, GVA: %#lx\n", __func__, gfn,
  73                         gva);
  74                 return KVM_INVALID_PAGE;
  75         }
  76
  77         if (kvm_mips_map_page(vcpu->kvm, gfn) < 0)
  78                 return KVM_INVALID_ADDR;
  79
  80         return (kvm->arch.guest_pmap[gfn] << PAGE_SHIFT) + offset;
  81 }
  82
  83 /* XXXKYMA: Must be called with interrupts disabled */
  84 int kvm_mips_handle_kseg0_tlb_fault(unsigned long badvaddr,
  85                                     struct kvm_vcpu *vcpu)
  86 {
  87         gfn_t gfn;
  88         kvm_pfn_t pfn0, pfn1;
  89         unsigned long vaddr = 0;
  90         unsigned long entryhi = 0, entrylo0 = 0, entrylo1 = 0;
  91         struct kvm *kvm = vcpu->kvm;
  92         const int flush_dcache_mask = 0;
  93         int ret;
  94
  95         if (KVM_GUEST_KSEGX(badvaddr) != KVM_GUEST_KSEG0) {
  96                 kvm_err("%s: Invalid BadVaddr: %#lx\n", __func__, badvaddr);
  97                 kvm_mips_dump_host_tlbs();
  98                 return -1;
  99         }
 100
 101         gfn = (KVM_GUEST_CPHYSADDR(badvaddr) >> PAGE_SHIFT);
 102         if ((gfn | 1) >= kvm->arch.guest_pmap_npages) {
 103                 kvm_err("%s: Invalid gfn: %#llx, BadVaddr: %#lx\n", __func__,
 104                         gfn, badvaddr);
 105                 kvm_mips_dump_host_tlbs();
 106                 return -1;
 107         }
 108         vaddr = badvaddr & (PAGE_MASK << 1);
 109
 110         if (kvm_mips_map_page(vcpu->kvm, gfn) < 0)
 111                 return -1;
 112
 113         if (kvm_mips_map_page(vcpu->kvm, gfn ^ 0x1) < 0)
 114                 return -1;
 115
 116         pfn0 = kvm->arch.guest_pmap[gfn & ~0x1];
 117         pfn1 = kvm->arch.guest_pmap[gfn | 0x1];
 118
 119         entrylo0 = mips3_paddr_to_tlbpfn(pfn0 << PAGE_SHIFT) |
 120                 ((_page_cachable_default >> _CACHE_SHIFT) << ENTRYLO_C_SHIFT) |
 121                 ENTRYLO_D | ENTRYLO_V;
 122         entrylo1 = mips3_paddr_to_tlbpfn(pfn1 << PAGE_SHIFT) |
 123                 ((_page_cachable_default >> _CACHE_SHIFT) << ENTRYLO_C_SHIFT) |
 124                 ENTRYLO_D | ENTRYLO_V;
 125
 126         preempt_disable();
 127         entryhi = (vaddr | kvm_mips_get_kernel_asid(vcpu));
 128         ret = kvm_mips_host_tlb_write(vcpu, entryhi, entrylo0, entrylo1,
 129                                       flush_dcache_mask);
 130         preempt_enable();
 131
 132         return ret;
 133 }
 134
 135 int kvm_mips_handle_mapped_seg_tlb_fault(struct kvm_vcpu *vcpu,
 136                                          struct kvm_mips_tlb *tlb)
 137 {
 138         unsigned long entryhi = 0, entrylo0 = 0, entrylo1 = 0;
 139         struct kvm *kvm = vcpu->kvm;
 140         kvm_pfn_t pfn0, pfn1;
 141         gfn_t gfn0, gfn1;
 142         long tlb_lo[2];
 143         int ret;
 144
 145         tlb_lo[0] = tlb->tlb_lo[0];
 146         tlb_lo[1] = tlb->tlb_lo[1];
 147
 148         /*
 149          * The commpage address must not be mapped to anything else if the guest
 150          * TLB contains entries nearby, or commpage accesses will break.
 151          */
 152         if (!((tlb->tlb_hi ^ KVM_GUEST_COMMPAGE_ADDR) &
 153                         VPN2_MASK & (PAGE_MASK << 1)))
 154                 tlb_lo[(KVM_GUEST_COMMPAGE_ADDR >> PAGE_SHIFT) & 1] = 0;
 155
 156         gfn0 = mips3_tlbpfn_to_paddr(tlb_lo[0]) >> PAGE_SHIFT;
 157         gfn1 = mips3_tlbpfn_to_paddr(tlb_lo[1]) >> PAGE_SHIFT;
 158         if (gfn0 >= kvm->arch.guest_pmap_npages ||
 159             gfn1 >= kvm->arch.guest_pmap_npages) {
 160                 kvm_err("%s: Invalid gfn: [%#llx, %#llx], EHi: %#lx\n",
 161                         __func__, gfn0, gfn1, tlb->tlb_hi);
 162                 kvm_mips_dump_guest_tlbs(vcpu);
 163                 return -1;
 164         }
 165
 166         if (kvm_mips_map_page(kvm, gfn0) < 0)
 167                 return -1;
 168
 169         if (kvm_mips_map_page(kvm, gfn1) < 0)
 170                 return -1;
 171
 172         pfn0 = kvm->arch.guest_pmap[gfn0];
 173         pfn1 = kvm->arch.guest_pmap[gfn1];
 174
 175         /* Get attributes from the Guest TLB */
 176         entrylo0 = mips3_paddr_to_tlbpfn(pfn0 << PAGE_SHIFT) |
 177                 ((_page_cachable_default >> _CACHE_SHIFT) << ENTRYLO_C_SHIFT) |
 178                 (tlb_lo[0] & ENTRYLO_D) |
 179                 (tlb_lo[0] & ENTRYLO_V);
 180         entrylo1 = mips3_paddr_to_tlbpfn(pfn1 << PAGE_SHIFT) |
 181                 ((_page_cachable_default >> _CACHE_SHIFT) << ENTRYLO_C_SHIFT) |
 182                 (tlb_lo[1] & ENTRYLO_D) |
 183                 (tlb_lo[1] & ENTRYLO_V);
 184
 185         kvm_debug("@ %#lx tlb_lo0: 0x%08lx tlb_lo1: 0x%08lx\n", vcpu->arch.pc,
 186                   tlb->tlb_lo[0], tlb->tlb_lo[1]);
 187
 188         preempt_disable();
 189         entryhi = (tlb->tlb_hi & VPN2_MASK) | (KVM_GUEST_KERNEL_MODE(vcpu) ?
 190                                                kvm_mips_get_kernel_asid(vcpu) :
 191                                                kvm_mips_get_user_asid(vcpu));
 192         ret = kvm_mips_host_tlb_write(vcpu, entryhi, entrylo0, entrylo1,
 193                                       tlb->tlb_mask);
 194         preempt_enable();
 195
 196         return ret;
 197 }
 198
 199 void kvm_get_new_mmu_context(struct mm_struct *mm, unsigned long cpu,
 200                              struct kvm_vcpu *vcpu)
 201 {
 202         unsigned long asid = asid_cache(cpu);
 203
 204         asid += cpu_asid_inc();
 205         if (!(asid & cpu_asid_mask(&cpu_data[cpu]))) {
 206                 if (cpu_has_vtag_icache)
 207                         flush_icache_all();
 208
 209                 kvm_local_flush_tlb_all();      /* start new asid cycle */
 210
 211                 if (!asid)      /* fix version if needed */
 212                         asid = asid_first_version(cpu);
 213         }
 214
 215         cpu_context(cpu, mm) = asid_cache(cpu) = asid;
 216 }
 217
 218 /**
 219  * kvm_mips_migrate_count() - Migrate timer.
 220  * @vcpu:       Virtual CPU.
 221  *
 222  * Migrate CP0_Count hrtimer to the current CPU by cancelling and restarting it
 223  * if it was running prior to being cancelled.
 224  *
 225  * Must be called when the VCPU is migrated to a different CPU to ensure that
 226  * timer expiry during guest execution interrupts the guest and causes the
 227  * interrupt to be delivered in a timely manner.
 228  */
 229 static void kvm_mips_migrate_count(struct kvm_vcpu *vcpu)
 230 {
 231         if (hrtimer_cancel(&vcpu->arch.comparecount_timer))
 232                 hrtimer_restart(&vcpu->arch.comparecount_timer);
 233 }
 234
 235 /* Restore ASID once we are scheduled back after preemption */
 236 void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 237 {
 238         unsigned long asid_mask = cpu_asid_mask(&cpu_data[cpu]);
 239         unsigned long flags;
 240         int newasid = 0;
 241
 242         kvm_debug("%s: vcpu %p, cpu: %d\n", __func__, vcpu, cpu);
 243
 244         /* Allocate new kernel and user ASIDs if needed */
 245
 246         local_irq_save(flags);
 247
 248         if ((vcpu->arch.guest_kernel_asid[cpu] ^ asid_cache(cpu)) &
 249                                                 asid_version_mask(cpu)) {
 250                 kvm_get_new_mmu_context(&vcpu->arch.guest_kernel_mm, cpu, vcpu);
 251                 vcpu->arch.guest_kernel_asid[cpu] =
 252                     vcpu->arch.guest_kernel_mm.context.asid[cpu];
 253                 kvm_get_new_mmu_context(&vcpu->arch.guest_user_mm, cpu, vcpu);
 254                 vcpu->arch.guest_user_asid[cpu] =
 255                     vcpu->arch.guest_user_mm.context.asid[cpu];
 256                 newasid++;
 257
 258                 kvm_debug("[%d]: cpu_context: %#lx\n", cpu,
 259                           cpu_context(cpu, current->mm));
 260                 kvm_debug("[%d]: Allocated new ASID for Guest Kernel: %#x\n",
 261                           cpu, vcpu->arch.guest_kernel_asid[cpu]);
 262                 kvm_debug("[%d]: Allocated new ASID for Guest User: %#x\n", cpu,
 263                           vcpu->arch.guest_user_asid[cpu]);
 264         }
 265
 266         if (vcpu->arch.last_sched_cpu != cpu) {
 267                 kvm_debug("[%d->%d]KVM VCPU[%d] switch\n",
 268                           vcpu->arch.last_sched_cpu, cpu, vcpu->vcpu_id);
 269                 /*
 270                  * Migrate the timer interrupt to the current CPU so that it
 271                  * always interrupts the guest and synchronously triggers a
 272                  * guest timer interrupt.
 273                  */
 274                 kvm_mips_migrate_count(vcpu);
 275         }
 276
 277         if (!newasid) {
 278                 /*
 279                  * If we preempted while the guest was executing, then reload
 280                  * the pre-empted ASID
 281                  */
 282                 if (current->flags & PF_VCPU) {
 283                         write_c0_entryhi(vcpu->arch.
 284                                          preempt_entryhi & asid_mask);
 285                         ehb();
 286                 }
 287         } else {
 288                 /* New ASIDs were allocated for the VM */
 289
 290                 /*
 291                  * Were we in guest context? If so then the pre-empted ASID is
 292                  * no longer valid, we need to set it to what it should be based
 293                  * on the mode of the Guest (Kernel/User)
 294                  */
 295                 if (current->flags & PF_VCPU) {
 296                         if (KVM_GUEST_KERNEL_MODE(vcpu))
 297                                 write_c0_entryhi(vcpu->arch.
 298                                                  guest_kernel_asid[cpu] &
 299                                                  asid_mask);
 300                         else
 301                                 write_c0_entryhi(vcpu->arch.
 302                                                  guest_user_asid[cpu] &
 303                                                  asid_mask);
 304                         ehb();
 305                 }
 306         }
 307
 308         /* restore guest state to registers */
 309         kvm_mips_callbacks->vcpu_set_regs(vcpu);
 310
 311         local_irq_restore(flags);
 312
 313 }
 314
 315 /* ASID can change if another task is scheduled during preemption */
 316 void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 317 {
 318         unsigned long flags;
 319         int cpu;
 320
 321         local_irq_save(flags);
 322
 323         cpu = smp_processor_id();
 324
 325         vcpu->arch.preempt_entryhi = read_c0_entryhi();
 326         vcpu->arch.last_sched_cpu = cpu;
 327
 328         /* save guest state in registers */
 329         kvm_mips_callbacks->vcpu_get_regs(vcpu);
 330
 331         if (((cpu_context(cpu, current->mm) ^ asid_cache(cpu)) &
 332              asid_version_mask(cpu))) {
 333                 kvm_debug("%s: Dropping MMU Context:  %#lx\n", __func__,
 334                           cpu_context(cpu, current->mm));
 335                 drop_mmu_context(current->mm, cpu);
 336         }
 337         write_c0_entryhi(cpu_asid(cpu, current->mm));
 338         ehb();
 339
 340         local_irq_restore(flags);
 341 }
 342
 343 u32 kvm_get_inst(u32 *opc, struct kvm_vcpu *vcpu)
 344 {
 345         struct mips_coproc *cop0 = vcpu->arch.cop0;
 346         unsigned long paddr, flags, vpn2, asid;
 347         unsigned long va = (unsigned long)opc;
 348         void *vaddr;
 349         u32 inst;
 350         int index;
 351
 352         if (KVM_GUEST_KSEGX(va) < KVM_GUEST_KSEG0 ||
 353             KVM_GUEST_KSEGX(va) == KVM_GUEST_KSEG23) {
 354                 local_irq_save(flags);
 355                 index = kvm_mips_host_tlb_lookup(vcpu, va);
 356                 if (index >= 0) {
 357                         inst = *(opc);
 358                 } else {
 359                         vpn2 = va & VPN2_MASK;
 360                         asid = kvm_read_c0_guest_entryhi(cop0) &
 361                                                 KVM_ENTRYHI_ASID;
 362                         index = kvm_mips_guest_tlb_lookup(vcpu, vpn2 | asid);
 363                         if (index < 0) {
 364                                 kvm_err("%s: get_user_failed for %p, vcpu: %p, ASID: %#lx\n",
 365                                         __func__, opc, vcpu, read_c0_entryhi());
 366                                 kvm_mips_dump_host_tlbs();
 367                                 kvm_mips_dump_guest_tlbs(vcpu);
 368                                 local_irq_restore(flags);
 369                                 return KVM_INVALID_INST;
 370                         }
 371                         if (kvm_mips_handle_mapped_seg_tlb_fault(vcpu,
 372                                                 &vcpu->arch.guest_tlb[index])) {
 373                                 kvm_err("%s: handling mapped seg tlb fault failed for %p, index: %u, vcpu: %p, ASID: %#lx\n",
 374                                         __func__, opc, index, vcpu,
 375                                         read_c0_entryhi());
 376                                 kvm_mips_dump_guest_tlbs(vcpu);
 377                                 local_irq_restore(flags);
 378                                 return KVM_INVALID_INST;
 379                         }
 380                         inst = *(opc);
 381                 }
 382                 local_irq_restore(flags);
 383         } else if (KVM_GUEST_KSEGX(va) == KVM_GUEST_KSEG0) {
 384                 paddr = kvm_mips_translate_guest_kseg0_to_hpa(vcpu, va);
 385                 vaddr = kmap_atomic(pfn_to_page(PHYS_PFN(paddr)));
 386                 vaddr += paddr & ~PAGE_MASK;
 387                 inst = *(u32 *)vaddr;
 388                 kunmap_atomic(vaddr);
 389         } else {
 390                 kvm_err("%s: illegal address: %p\n", __func__, opc);
 391                 return KVM_INVALID_INST;
 392         }
 393
 394         return inst;
 395 }