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 = kvm_mips_gfn_to_pfn(kvm, gfn);
  41
  42         if (kvm_mips_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         int even;
  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 >= 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         even = !(gfn & 0x1);
 109         vaddr = badvaddr & (PAGE_MASK << 1);
 110
 111         if (kvm_mips_map_page(vcpu->kvm, gfn) < 0)
 112                 return -1;
 113
 114         if (kvm_mips_map_page(vcpu->kvm, gfn ^ 0x1) < 0)
 115                 return -1;
 116
 117         if (even) {
 118                 pfn0 = kvm->arch.guest_pmap[gfn];
 119                 pfn1 = kvm->arch.guest_pmap[gfn ^ 0x1];
 120         } else {
 121                 pfn0 = kvm->arch.guest_pmap[gfn ^ 0x1];
 122                 pfn1 = kvm->arch.guest_pmap[gfn];
 123         }
 124
 125         entrylo0 = mips3_paddr_to_tlbpfn(pfn0 << PAGE_SHIFT) | (0x3 << 3) |
 126                    (1 << 2) | (0x1 << 1);
 127         entrylo1 = mips3_paddr_to_tlbpfn(pfn1 << PAGE_SHIFT) | (0x3 << 3) |
 128                    (1 << 2) | (0x1 << 1);
 129
 130         preempt_disable();
 131         entryhi = (vaddr | kvm_mips_get_kernel_asid(vcpu));
 132         ret = kvm_mips_host_tlb_write(vcpu, entryhi, entrylo0, entrylo1,
 133                                       flush_dcache_mask);
 134         preempt_enable();
 135
 136         return ret;
 137 }
 138
 139 int kvm_mips_handle_mapped_seg_tlb_fault(struct kvm_vcpu *vcpu,
 140                                          struct kvm_mips_tlb *tlb,
 141                                          unsigned long *hpa0,
 142                                          unsigned long *hpa1)
 143 {
 144         unsigned long entryhi = 0, entrylo0 = 0, entrylo1 = 0;
 145         struct kvm *kvm = vcpu->kvm;
 146         kvm_pfn_t pfn0, pfn1;
 147         int ret;
 148
 149         if ((tlb->tlb_hi & VPN2_MASK) == 0) {
 150                 pfn0 = 0;
 151                 pfn1 = 0;
 152         } else {
 153                 if (kvm_mips_map_page(kvm, mips3_tlbpfn_to_paddr(tlb->tlb_lo0)
 154                                            >> PAGE_SHIFT) < 0)
 155                         return -1;
 156
 157                 if (kvm_mips_map_page(kvm, mips3_tlbpfn_to_paddr(tlb->tlb_lo1)
 158                                            >> PAGE_SHIFT) < 0)
 159                         return -1;
 160
 161                 pfn0 = kvm->arch.guest_pmap[mips3_tlbpfn_to_paddr(tlb->tlb_lo0)
 162                                             >> PAGE_SHIFT];
 163                 pfn1 = kvm->arch.guest_pmap[mips3_tlbpfn_to_paddr(tlb->tlb_lo1)
 164                                             >> PAGE_SHIFT];
 165         }
 166
 167         if (hpa0)
 168                 *hpa0 = pfn0 << PAGE_SHIFT;
 169
 170         if (hpa1)
 171                 *hpa1 = pfn1 << PAGE_SHIFT;
 172
 173         /* Get attributes from the Guest TLB */
 174         entrylo0 = mips3_paddr_to_tlbpfn(pfn0 << PAGE_SHIFT) | (0x3 << 3) |
 175                    (tlb->tlb_lo0 & MIPS3_PG_D) | (tlb->tlb_lo0 & MIPS3_PG_V);
 176         entrylo1 = mips3_paddr_to_tlbpfn(pfn1 << PAGE_SHIFT) | (0x3 << 3) |
 177                    (tlb->tlb_lo1 & MIPS3_PG_D) | (tlb->tlb_lo1 & MIPS3_PG_V);
 178
 179         kvm_debug("@ %#lx tlb_lo0: 0x%08lx tlb_lo1: 0x%08lx\n", vcpu->arch.pc,
 180                   tlb->tlb_lo0, tlb->tlb_lo1);
 181
 182         preempt_disable();
 183         entryhi = (tlb->tlb_hi & VPN2_MASK) | (KVM_GUEST_KERNEL_MODE(vcpu) ?
 184                                                kvm_mips_get_kernel_asid(vcpu) :
 185                                                kvm_mips_get_user_asid(vcpu));
 186         ret = kvm_mips_host_tlb_write(vcpu, entryhi, entrylo0, entrylo1,
 187                                       tlb->tlb_mask);
 188         preempt_enable();
 189
 190         return ret;
 191 }
 192
 193 void kvm_get_new_mmu_context(struct mm_struct *mm, unsigned long cpu,
 194                              struct kvm_vcpu *vcpu)
 195 {
 196         unsigned long asid = asid_cache(cpu);
 197
 198         asid += cpu_asid_inc();
 199         if (!(asid & cpu_asid_mask(&cpu_data[cpu]))) {
 200                 if (cpu_has_vtag_icache)
 201                         flush_icache_all();
 202
 203                 kvm_local_flush_tlb_all();      /* start new asid cycle */
 204
 205                 if (!asid)      /* fix version if needed */
 206                         asid = asid_first_version(cpu);
 207         }
 208
 209         cpu_context(cpu, mm) = asid_cache(cpu) = asid;
 210 }
 211
 212 /**
 213  * kvm_mips_migrate_count() - Migrate timer.
 214  * @vcpu:       Virtual CPU.
 215  *
 216  * Migrate CP0_Count hrtimer to the current CPU by cancelling and restarting it
 217  * if it was running prior to being cancelled.
 218  *
 219  * Must be called when the VCPU is migrated to a different CPU to ensure that
 220  * timer expiry during guest execution interrupts the guest and causes the
 221  * interrupt to be delivered in a timely manner.
 222  */
 223 static void kvm_mips_migrate_count(struct kvm_vcpu *vcpu)
 224 {
 225         if (hrtimer_cancel(&vcpu->arch.comparecount_timer))
 226                 hrtimer_restart(&vcpu->arch.comparecount_timer);
 227 }
 228
 229 /* Restore ASID once we are scheduled back after preemption */
 230 void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 231 {
 232         unsigned long asid_mask = cpu_asid_mask(&cpu_data[cpu]);
 233         unsigned long flags;
 234         int newasid = 0;
 235
 236         kvm_debug("%s: vcpu %p, cpu: %d\n", __func__, vcpu, cpu);
 237
 238         /* Allocate new kernel and user ASIDs if needed */
 239
 240         local_irq_save(flags);
 241
 242         if ((vcpu->arch.guest_kernel_asid[cpu] ^ asid_cache(cpu)) &
 243                                                 asid_version_mask(cpu)) {
 244                 kvm_get_new_mmu_context(&vcpu->arch.guest_kernel_mm, cpu, vcpu);
 245                 vcpu->arch.guest_kernel_asid[cpu] =
 246                     vcpu->arch.guest_kernel_mm.context.asid[cpu];
 247                 kvm_get_new_mmu_context(&vcpu->arch.guest_user_mm, cpu, vcpu);
 248                 vcpu->arch.guest_user_asid[cpu] =
 249                     vcpu->arch.guest_user_mm.context.asid[cpu];
 250                 newasid++;
 251
 252                 kvm_debug("[%d]: cpu_context: %#lx\n", cpu,
 253                           cpu_context(cpu, current->mm));
 254                 kvm_debug("[%d]: Allocated new ASID for Guest Kernel: %#x\n",
 255                           cpu, vcpu->arch.guest_kernel_asid[cpu]);
 256                 kvm_debug("[%d]: Allocated new ASID for Guest User: %#x\n", cpu,
 257                           vcpu->arch.guest_user_asid[cpu]);
 258         }
 259
 260         if (vcpu->arch.last_sched_cpu != cpu) {
 261                 kvm_debug("[%d->%d]KVM VCPU[%d] switch\n",
 262                           vcpu->arch.last_sched_cpu, cpu, vcpu->vcpu_id);
 263                 /*
 264                  * Migrate the timer interrupt to the current CPU so that it
 265                  * always interrupts the guest and synchronously triggers a
 266                  * guest timer interrupt.
 267                  */
 268                 kvm_mips_migrate_count(vcpu);
 269         }
 270
 271         if (!newasid) {
 272                 /*
 273                  * If we preempted while the guest was executing, then reload
 274                  * the pre-empted ASID
 275                  */
 276                 if (current->flags & PF_VCPU) {
 277                         write_c0_entryhi(vcpu->arch.
 278                                          preempt_entryhi & asid_mask);
 279                         ehb();
 280                 }
 281         } else {
 282                 /* New ASIDs were allocated for the VM */
 283
 284                 /*
 285                  * Were we in guest context? If so then the pre-empted ASID is
 286                  * no longer valid, we need to set it to what it should be based
 287                  * on the mode of the Guest (Kernel/User)
 288                  */
 289                 if (current->flags & PF_VCPU) {
 290                         if (KVM_GUEST_KERNEL_MODE(vcpu))
 291                                 write_c0_entryhi(vcpu->arch.
 292                                                  guest_kernel_asid[cpu] &
 293                                                  asid_mask);
 294                         else
 295                                 write_c0_entryhi(vcpu->arch.
 296                                                  guest_user_asid[cpu] &
 297                                                  asid_mask);
 298                         ehb();
 299                 }
 300         }
 301
 302         /* restore guest state to registers */
 303         kvm_mips_callbacks->vcpu_set_regs(vcpu);
 304
 305         local_irq_restore(flags);
 306
 307 }
 308
 309 /* ASID can change if another task is scheduled during preemption */
 310 void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 311 {
 312         unsigned long flags;
 313         int cpu;
 314
 315         local_irq_save(flags);
 316
 317         cpu = smp_processor_id();
 318
 319         vcpu->arch.preempt_entryhi = read_c0_entryhi();
 320         vcpu->arch.last_sched_cpu = cpu;
 321
 322         /* save guest state in registers */
 323         kvm_mips_callbacks->vcpu_get_regs(vcpu);
 324
 325         if (((cpu_context(cpu, current->mm) ^ asid_cache(cpu)) &
 326              asid_version_mask(cpu))) {
 327                 kvm_debug("%s: Dropping MMU Context:  %#lx\n", __func__,
 328                           cpu_context(cpu, current->mm));
 329                 drop_mmu_context(current->mm, cpu);
 330         }
 331         write_c0_entryhi(cpu_asid(cpu, current->mm));
 332         ehb();
 333
 334         local_irq_restore(flags);
 335 }
 336
 337 u32 kvm_get_inst(u32 *opc, struct kvm_vcpu *vcpu)
 338 {
 339         struct mips_coproc *cop0 = vcpu->arch.cop0;
 340         unsigned long paddr, flags, vpn2, asid;
 341         u32 inst;
 342         int index;
 343
 344         if (KVM_GUEST_KSEGX((unsigned long) opc) < KVM_GUEST_KSEG0 ||
 345             KVM_GUEST_KSEGX((unsigned long) opc) == KVM_GUEST_KSEG23) {
 346                 local_irq_save(flags);
 347                 index = kvm_mips_host_tlb_lookup(vcpu, (unsigned long) opc);
 348                 if (index >= 0) {
 349                         inst = *(opc);
 350                 } else {
 351                         vpn2 = (unsigned long) opc & VPN2_MASK;
 352                         asid = kvm_read_c0_guest_entryhi(cop0) &
 353                                                 KVM_ENTRYHI_ASID;
 354                         index = kvm_mips_guest_tlb_lookup(vcpu, vpn2 | asid);
 355                         if (index < 0) {
 356                                 kvm_err("%s: get_user_failed for %p, vcpu: %p, ASID: %#lx\n",
 357                                         __func__, opc, vcpu, read_c0_entryhi());
 358                                 kvm_mips_dump_host_tlbs();
 359                                 local_irq_restore(flags);
 360                                 return KVM_INVALID_INST;
 361                         }
 362                         kvm_mips_handle_mapped_seg_tlb_fault(vcpu,
 363                                                              &vcpu->arch.
 364                                                              guest_tlb[index],
 365                                                              NULL, NULL);
 366                         inst = *(opc);
 367                 }
 368                 local_irq_restore(flags);
 369         } else if (KVM_GUEST_KSEGX(opc) == KVM_GUEST_KSEG0) {
 370                 paddr =
 371                     kvm_mips_translate_guest_kseg0_to_hpa(vcpu,
 372                                                           (unsigned long) opc);
 373                 inst = *(u32 *) CKSEG0ADDR(paddr);
 374         } else {
 375                 kvm_err("%s: illegal address: %p\n", __func__, opc);
 376                 return KVM_INVALID_INST;
 377         }
 378
 379         return inst;
 380 }