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_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 >= 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         long tlb_lo[2];
 142         int ret;
 143
 144         tlb_lo[0] = tlb->tlb_lo[0];
 145         tlb_lo[1] = tlb->tlb_lo[1];
 146
 147         /*
 148          * The commpage address must not be mapped to anything else if the guest
 149          * TLB contains entries nearby, or commpage accesses will break.
 150          */
 151         if (!((tlb->tlb_hi ^ KVM_GUEST_COMMPAGE_ADDR) &
 152                         VPN2_MASK & (PAGE_MASK << 1)))
 153                 tlb_lo[(KVM_GUEST_COMMPAGE_ADDR >> PAGE_SHIFT) & 1] = 0;
 154
 155         if (kvm_mips_map_page(kvm, mips3_tlbpfn_to_paddr(tlb_lo[0])
 156                                    >> PAGE_SHIFT) < 0)
 157                 return -1;
 158
 159         if (kvm_mips_map_page(kvm, mips3_tlbpfn_to_paddr(tlb_lo[1])
 160                                    >> PAGE_SHIFT) < 0)
 161                 return -1;
 162
 163         pfn0 = kvm->arch.guest_pmap[
 164                 mips3_tlbpfn_to_paddr(tlb_lo[0]) >> PAGE_SHIFT];
 165         pfn1 = kvm->arch.guest_pmap[
 166                 mips3_tlbpfn_to_paddr(tlb_lo[1]) >> PAGE_SHIFT];
 167
 168         /* Get attributes from the Guest TLB */
 169         entrylo0 = mips3_paddr_to_tlbpfn(pfn0 << PAGE_SHIFT) |
 170                 ((_page_cachable_default >> _CACHE_SHIFT) << ENTRYLO_C_SHIFT) |
 171                 (tlb_lo[0] & ENTRYLO_D) |
 172                 (tlb_lo[0] & ENTRYLO_V);
 173         entrylo1 = mips3_paddr_to_tlbpfn(pfn1 << PAGE_SHIFT) |
 174                 ((_page_cachable_default >> _CACHE_SHIFT) << ENTRYLO_C_SHIFT) |
 175                 (tlb_lo[1] & ENTRYLO_D) |
 176                 (tlb_lo[1] & ENTRYLO_V);
 177
 178         kvm_debug("@ %#lx tlb_lo0: 0x%08lx tlb_lo1: 0x%08lx\n", vcpu->arch.pc,
 179                   tlb->tlb_lo[0], tlb->tlb_lo[1]);
 180
 181         preempt_disable();
 182         entryhi = (tlb->tlb_hi & VPN2_MASK) | (KVM_GUEST_KERNEL_MODE(vcpu) ?
 183                                                kvm_mips_get_kernel_asid(vcpu) :
 184                                                kvm_mips_get_user_asid(vcpu));
 185         ret = kvm_mips_host_tlb_write(vcpu, entryhi, entrylo0, entrylo1,
 186                                       tlb->tlb_mask);
 187         preempt_enable();
 188
 189         return ret;
 190 }
 191
 192 void kvm_get_new_mmu_context(struct mm_struct *mm, unsigned long cpu,
 193                              struct kvm_vcpu *vcpu)
 194 {
 195         unsigned long asid = asid_cache(cpu);
 196
 197         asid += cpu_asid_inc();
 198         if (!(asid & cpu_asid_mask(&cpu_data[cpu]))) {
 199                 if (cpu_has_vtag_icache)
 200                         flush_icache_all();
 201
 202                 kvm_local_flush_tlb_all();      /* start new asid cycle */
 203
 204                 if (!asid)      /* fix version if needed */
 205                         asid = asid_first_version(cpu);
 206         }
 207
 208         cpu_context(cpu, mm) = asid_cache(cpu) = asid;
 209 }
 210
 211 /**
 212  * kvm_mips_migrate_count() - Migrate timer.
 213  * @vcpu:       Virtual CPU.
 214  *
 215  * Migrate CP0_Count hrtimer to the current CPU by cancelling and restarting it
 216  * if it was running prior to being cancelled.
 217  *
 218  * Must be called when the VCPU is migrated to a different CPU to ensure that
 219  * timer expiry during guest execution interrupts the guest and causes the
 220  * interrupt to be delivered in a timely manner.
 221  */
 222 static void kvm_mips_migrate_count(struct kvm_vcpu *vcpu)
 223 {
 224         if (hrtimer_cancel(&vcpu->arch.comparecount_timer))
 225                 hrtimer_restart(&vcpu->arch.comparecount_timer);
 226 }
 227
 228 /* Restore ASID once we are scheduled back after preemption */
 229 void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 230 {
 231         unsigned long asid_mask = cpu_asid_mask(&cpu_data[cpu]);
 232         unsigned long flags;
 233         int newasid = 0;
 234
 235         kvm_debug("%s: vcpu %p, cpu: %d\n", __func__, vcpu, cpu);
 236
 237         /* Allocate new kernel and user ASIDs if needed */
 238
 239         local_irq_save(flags);
 240
 241         if ((vcpu->arch.guest_kernel_asid[cpu] ^ asid_cache(cpu)) &
 242                                                 asid_version_mask(cpu)) {
 243                 kvm_get_new_mmu_context(&vcpu->arch.guest_kernel_mm, cpu, vcpu);
 244                 vcpu->arch.guest_kernel_asid[cpu] =
 245                     vcpu->arch.guest_kernel_mm.context.asid[cpu];
 246                 kvm_get_new_mmu_context(&vcpu->arch.guest_user_mm, cpu, vcpu);
 247                 vcpu->arch.guest_user_asid[cpu] =
 248                     vcpu->arch.guest_user_mm.context.asid[cpu];
 249                 newasid++;
 250
 251                 kvm_debug("[%d]: cpu_context: %#lx\n", cpu,
 252                           cpu_context(cpu, current->mm));
 253                 kvm_debug("[%d]: Allocated new ASID for Guest Kernel: %#x\n",
 254                           cpu, vcpu->arch.guest_kernel_asid[cpu]);
 255                 kvm_debug("[%d]: Allocated new ASID for Guest User: %#x\n", cpu,
 256                           vcpu->arch.guest_user_asid[cpu]);
 257         }
 258
 259         if (vcpu->arch.last_sched_cpu != cpu) {
 260                 kvm_debug("[%d->%d]KVM VCPU[%d] switch\n",
 261                           vcpu->arch.last_sched_cpu, cpu, vcpu->vcpu_id);
 262                 /*
 263                  * Migrate the timer interrupt to the current CPU so that it
 264                  * always interrupts the guest and synchronously triggers a
 265                  * guest timer interrupt.
 266                  */
 267                 kvm_mips_migrate_count(vcpu);
 268         }
 269
 270         if (!newasid) {
 271                 /*
 272                  * If we preempted while the guest was executing, then reload
 273                  * the pre-empted ASID
 274                  */
 275                 if (current->flags & PF_VCPU) {
 276                         write_c0_entryhi(vcpu->arch.
 277                                          preempt_entryhi & asid_mask);
 278                         ehb();
 279                 }
 280         } else {
 281                 /* New ASIDs were allocated for the VM */
 282
 283                 /*
 284                  * Were we in guest context? If so then the pre-empted ASID is
 285                  * no longer valid, we need to set it to what it should be based
 286                  * on the mode of the Guest (Kernel/User)
 287                  */
 288                 if (current->flags & PF_VCPU) {
 289                         if (KVM_GUEST_KERNEL_MODE(vcpu))
 290                                 write_c0_entryhi(vcpu->arch.
 291                                                  guest_kernel_asid[cpu] &
 292                                                  asid_mask);
 293                         else
 294                                 write_c0_entryhi(vcpu->arch.
 295                                                  guest_user_asid[cpu] &
 296                                                  asid_mask);
 297                         ehb();
 298                 }
 299         }
 300
 301         /* restore guest state to registers */
 302         kvm_mips_callbacks->vcpu_set_regs(vcpu);
 303
 304         local_irq_restore(flags);
 305
 306 }
 307
 308 /* ASID can change if another task is scheduled during preemption */
 309 void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 310 {
 311         unsigned long flags;
 312         int cpu;
 313
 314         local_irq_save(flags);
 315
 316         cpu = smp_processor_id();
 317
 318         vcpu->arch.preempt_entryhi = read_c0_entryhi();
 319         vcpu->arch.last_sched_cpu = cpu;
 320
 321         /* save guest state in registers */
 322         kvm_mips_callbacks->vcpu_get_regs(vcpu);
 323
 324         if (((cpu_context(cpu, current->mm) ^ asid_cache(cpu)) &
 325              asid_version_mask(cpu))) {
 326                 kvm_debug("%s: Dropping MMU Context:  %#lx\n", __func__,
 327                           cpu_context(cpu, current->mm));
 328                 drop_mmu_context(current->mm, cpu);
 329         }
 330         write_c0_entryhi(cpu_asid(cpu, current->mm));
 331         ehb();
 332
 333         local_irq_restore(flags);
 334 }
 335
 336 u32 kvm_get_inst(u32 *opc, struct kvm_vcpu *vcpu)
 337 {
 338         struct mips_coproc *cop0 = vcpu->arch.cop0;
 339         unsigned long paddr, flags, vpn2, asid;
 340         unsigned long va = (unsigned long)opc;
 341         void *vaddr;
 342         u32 inst;
 343         int index;
 344
 345         if (KVM_GUEST_KSEGX(va) < KVM_GUEST_KSEG0 ||
 346             KVM_GUEST_KSEGX(va) == KVM_GUEST_KSEG23) {
 347                 local_irq_save(flags);
 348                 index = kvm_mips_host_tlb_lookup(vcpu, va);
 349                 if (index >= 0) {
 350                         inst = *(opc);
 351                 } else {
 352                         vpn2 = va & VPN2_MASK;
 353                         asid = kvm_read_c0_guest_entryhi(cop0) &
 354                                                 KVM_ENTRYHI_ASID;
 355                         index = kvm_mips_guest_tlb_lookup(vcpu, vpn2 | asid);
 356                         if (index < 0) {
 357                                 kvm_err("%s: get_user_failed for %p, vcpu: %p, ASID: %#lx\n",
 358                                         __func__, opc, vcpu, read_c0_entryhi());
 359                                 kvm_mips_dump_host_tlbs();
 360                                 kvm_mips_dump_guest_tlbs(vcpu);
 361                                 local_irq_restore(flags);
 362                                 return KVM_INVALID_INST;
 363                         }
 364                         kvm_mips_handle_mapped_seg_tlb_fault(vcpu,
 365                                                              &vcpu->arch.
 366                                                              guest_tlb[index]);
 367                         inst = *(opc);
 368                 }
 369                 local_irq_restore(flags);
 370         } else if (KVM_GUEST_KSEGX(va) == KVM_GUEST_KSEG0) {
 371                 paddr = kvm_mips_translate_guest_kseg0_to_hpa(vcpu, va);
 372                 vaddr = kmap_atomic(pfn_to_page(PHYS_PFN(paddr)));
 373                 vaddr += paddr & ~PAGE_MASK;
 374                 inst = *(u32 *)vaddr;
 375                 kunmap_atomic(vaddr);
 376         } else {
 377                 kvm_err("%s: illegal address: %p\n", __func__, opc);
 378                 return KVM_INVALID_INST;
 379         }
 380
 381         return inst;
 382 }