arch/powerpc/kvm/book3s_64_vio_hv.c

   1 /*
   2  * This program is free software; you can redistribute it and/or modify
   3  * it under the terms of the GNU General Public License, version 2, as
   4  * published by the Free Software Foundation.
   5  *
   6  * This program is distributed in the hope that it will be useful,
   7  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   8  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   9  * GNU General Public License for more details.
  10  *
  11  * You should have received a copy of the GNU General Public License
  12  * along with this program; if not, write to the Free Software
  13  * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  14  *
  15  * Copyright 2010 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
  16  * Copyright 2011 David Gibson, IBM Corporation <dwg@au1.ibm.com>
  17  * Copyright 2016 Alexey Kardashevskiy, IBM Corporation <aik@au1.ibm.com>
  18  */
  19
  20 #include <linux/types.h>
  21 #include <linux/string.h>
  22 #include <linux/kvm.h>
  23 #include <linux/kvm_host.h>
  24 #include <linux/highmem.h>
  25 #include <linux/gfp.h>
  26 #include <linux/slab.h>
  27 #include <linux/hugetlb.h>
  28 #include <linux/list.h>
  29
  30 #include <asm/tlbflush.h>
  31 #include <asm/kvm_ppc.h>
  32 #include <asm/kvm_book3s.h>
  33 #include <asm/mmu-hash64.h>
  34 #include <asm/mmu_context.h>
  35 #include <asm/hvcall.h>
  36 #include <asm/synch.h>
  37 #include <asm/ppc-opcode.h>
  38 #include <asm/kvm_host.h>
  39 #include <asm/udbg.h>
  40 #include <asm/iommu.h>
  41 #include <asm/tce.h>
  42 #include <asm/iommu.h>
  43
  44 #define TCES_PER_PAGE   (PAGE_SIZE / sizeof(u64))
  45
  46 /*
  47  * Finds a TCE table descriptor by LIOBN.
  48  *
  49  * WARNING: This will be called in real or virtual mode on HV KVM and virtual
  50  *          mode on PR KVM
  51  */
  52 struct kvmppc_spapr_tce_table *kvmppc_find_table(struct kvm_vcpu *vcpu,
  53                 unsigned long liobn)
  54 {
  55         struct kvm *kvm = vcpu->kvm;
  56         struct kvmppc_spapr_tce_table *stt;
  57
  58         list_for_each_entry_lockless(stt, &kvm->arch.spapr_tce_tables, list)
  59                 if (stt->liobn == liobn)
  60                         return stt;
  61
  62         return NULL;
  63 }
  64 EXPORT_SYMBOL_GPL(kvmppc_find_table);
  65
  66 /*
  67  * Validates IO address.
  68  *
  69  * WARNING: This will be called in real-mode on HV KVM and virtual
  70  *          mode on PR KVM
  71  */
  72 long kvmppc_ioba_validate(struct kvmppc_spapr_tce_table *stt,
  73                 unsigned long ioba, unsigned long npages)
  74 {
  75         unsigned long mask = (1ULL << stt->page_shift) - 1;
  76         unsigned long idx = ioba >> stt->page_shift;
  77
  78         if ((ioba & mask) || (idx + npages > stt->size) || (idx + npages < idx))
  79                 return H_PARAMETER;
  80
  81         return H_SUCCESS;
  82 }
  83 EXPORT_SYMBOL_GPL(kvmppc_ioba_validate);
  84
  85 /*
  86  * Validates TCE address.
  87  * At the moment flags and page mask are validated.
  88  * As the host kernel does not access those addresses (just puts them
  89  * to the table and user space is supposed to process them), we can skip
  90  * checking other things (such as TCE is a guest RAM address or the page
  91  * was actually allocated).
  92  *
  93  * WARNING: This will be called in real-mode on HV KVM and virtual
  94  *          mode on PR KVM
  95  */
  96 long kvmppc_tce_validate(struct kvmppc_spapr_tce_table *stt, unsigned long tce)
  97 {
  98         unsigned long page_mask = ~((1ULL << stt->page_shift) - 1);
  99         unsigned long mask = ~(page_mask | TCE_PCI_WRITE | TCE_PCI_READ);
 100
 101         if (tce & mask)
 102                 return H_PARAMETER;
 103
 104         return H_SUCCESS;
 105 }
 106 EXPORT_SYMBOL_GPL(kvmppc_tce_validate);
 107
 108 /* Note on the use of page_address() in real mode,
 109  *
 110  * It is safe to use page_address() in real mode on ppc64 because
 111  * page_address() is always defined as lowmem_page_address()
 112  * which returns __va(PFN_PHYS(page_to_pfn(page))) which is arithmetic
 113  * operation and does not access page struct.
 114  *
 115  * Theoretically page_address() could be defined different
 116  * but either WANT_PAGE_VIRTUAL or HASHED_PAGE_VIRTUAL
 117  * would have to be enabled.
 118  * WANT_PAGE_VIRTUAL is never enabled on ppc32/ppc64,
 119  * HASHED_PAGE_VIRTUAL could be enabled for ppc32 only and only
 120  * if CONFIG_HIGHMEM is defined. As CONFIG_SPARSEMEM_VMEMMAP
 121  * is not expected to be enabled on ppc32, page_address()
 122  * is safe for ppc32 as well.
 123  *
 124  * WARNING: This will be called in real-mode on HV KVM and virtual
 125  *          mode on PR KVM
 126  */
 127 static u64 *kvmppc_page_address(struct page *page)
 128 {
 129 #if defined(HASHED_PAGE_VIRTUAL) || defined(WANT_PAGE_VIRTUAL)
 130 #error TODO: fix to avoid page_address() here
 131 #endif
 132         return (u64 *) page_address(page);
 133 }
 134
 135 /*
 136  * Handles TCE requests for emulated devices.
 137  * Puts guest TCE values to the table and expects user space to convert them.
 138  * Called in both real and virtual modes.
 139  * Cannot fail so kvmppc_tce_validate must be called before it.
 140  *
 141  * WARNING: This will be called in real-mode on HV KVM and virtual
 142  *          mode on PR KVM
 143  */
 144 void kvmppc_tce_put(struct kvmppc_spapr_tce_table *stt,
 145                 unsigned long idx, unsigned long tce)
 146 {
 147         struct page *page;
 148         u64 *tbl;
 149
 150         page = stt->pages[idx / TCES_PER_PAGE];
 151         tbl = kvmppc_page_address(page);
 152
 153         tbl[idx % TCES_PER_PAGE] = tce;
 154 }
 155 EXPORT_SYMBOL_GPL(kvmppc_tce_put);
 156
 157 long kvmppc_gpa_to_ua(struct kvm *kvm, unsigned long gpa,
 158                 unsigned long *ua, unsigned long **prmap)
 159 {
 160         unsigned long gfn = gpa >> PAGE_SHIFT;
 161         struct kvm_memory_slot *memslot;
 162
 163         memslot = search_memslots(kvm_memslots(kvm), gfn);
 164         if (!memslot)
 165                 return -EINVAL;
 166
 167         *ua = __gfn_to_hva_memslot(memslot, gfn) |
 168                 (gpa & ~(PAGE_MASK | TCE_PCI_READ | TCE_PCI_WRITE));
 169
 170 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
 171         if (prmap)
 172                 *prmap = &memslot->arch.rmap[gfn - memslot->base_gfn];
 173 #endif
 174
 175         return 0;
 176 }
 177 EXPORT_SYMBOL_GPL(kvmppc_gpa_to_ua);
 178
 179 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
 180 long kvmppc_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn,
 181                       unsigned long ioba, unsigned long tce)
 182 {
 183         struct kvmppc_spapr_tce_table *stt = kvmppc_find_table(vcpu, liobn);
 184         long ret;
 185
 186         /* udbg_printf("H_PUT_TCE(): liobn=0x%lx ioba=0x%lx, tce=0x%lx\n", */
 187         /*          liobn, ioba, tce); */
 188
 189         if (!stt)
 190                 return H_TOO_HARD;
 191
 192         ret = kvmppc_ioba_validate(stt, ioba, 1);
 193         if (ret != H_SUCCESS)
 194                 return ret;
 195
 196         ret = kvmppc_tce_validate(stt, tce);
 197         if (ret != H_SUCCESS)
 198                 return ret;
 199
 200         kvmppc_tce_put(stt, ioba >> stt->page_shift, tce);
 201
 202         return H_SUCCESS;
 203 }
 204 EXPORT_SYMBOL_GPL(kvmppc_h_put_tce);
 205
 206 static long kvmppc_rm_ua_to_hpa(struct kvm_vcpu *vcpu,
 207                 unsigned long ua, unsigned long *phpa)
 208 {
 209         pte_t *ptep, pte;
 210         unsigned shift = 0;
 211
 212         ptep = __find_linux_pte_or_hugepte(vcpu->arch.pgdir, ua, NULL, &shift);
 213         if (!ptep || !pte_present(*ptep))
 214                 return -ENXIO;
 215         pte = *ptep;
 216
 217         if (!shift)
 218                 shift = PAGE_SHIFT;
 219
 220         /* Avoid handling anything potentially complicated in realmode */
 221         if (shift > PAGE_SHIFT)
 222                 return -EAGAIN;
 223
 224         if (!pte_young(pte))
 225                 return -EAGAIN;
 226
 227         *phpa = (pte_pfn(pte) << PAGE_SHIFT) | (ua & ((1ULL << shift) - 1)) |
 228                         (ua & ~PAGE_MASK);
 229
 230         return 0;
 231 }
 232
 233 long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
 234                 unsigned long liobn, unsigned long ioba,
 235                 unsigned long tce_list, unsigned long npages)
 236 {
 237         struct kvmppc_spapr_tce_table *stt;
 238         long i, ret = H_SUCCESS;
 239         unsigned long tces, entry, ua = 0;
 240         unsigned long *rmap = NULL;
 241
 242         stt = kvmppc_find_table(vcpu, liobn);
 243         if (!stt)
 244                 return H_TOO_HARD;
 245
 246         entry = ioba >> stt->page_shift;
 247         /*
 248          * The spec says that the maximum size of the list is 512 TCEs
 249          * so the whole table addressed resides in 4K page
 250          */
 251         if (npages > 512)
 252                 return H_PARAMETER;
 253
 254         if (tce_list & (SZ_4K - 1))
 255                 return H_PARAMETER;
 256
 257         ret = kvmppc_ioba_validate(stt, ioba, npages);
 258         if (ret != H_SUCCESS)
 259                 return ret;
 260
 261         if (kvmppc_gpa_to_ua(vcpu->kvm, tce_list, &ua, &rmap))
 262                 return H_TOO_HARD;
 263
 264         rmap = (void *) vmalloc_to_phys(rmap);
 265
 266         /*
 267          * Synchronize with the MMU notifier callbacks in
 268          * book3s_64_mmu_hv.c (kvm_unmap_hva_hv etc.).
 269          * While we have the rmap lock, code running on other CPUs
 270          * cannot finish unmapping the host real page that backs
 271          * this guest real page, so we are OK to access the host
 272          * real page.
 273          */
 274         lock_rmap(rmap);
 275         if (kvmppc_rm_ua_to_hpa(vcpu, ua, &tces)) {
 276                 ret = H_TOO_HARD;
 277                 goto unlock_exit;
 278         }
 279
 280         for (i = 0; i < npages; ++i) {
 281                 unsigned long tce = be64_to_cpu(((u64 *)tces)[i]);
 282
 283                 ret = kvmppc_tce_validate(stt, tce);
 284                 if (ret != H_SUCCESS)
 285                         goto unlock_exit;
 286
 287                 kvmppc_tce_put(stt, entry + i, tce);
 288         }
 289
 290 unlock_exit:
 291         unlock_rmap(rmap);
 292
 293         return ret;
 294 }
 295
 296 long kvmppc_h_stuff_tce(struct kvm_vcpu *vcpu,
 297                 unsigned long liobn, unsigned long ioba,
 298                 unsigned long tce_value, unsigned long npages)
 299 {
 300         struct kvmppc_spapr_tce_table *stt;
 301         long i, ret;
 302
 303         stt = kvmppc_find_table(vcpu, liobn);
 304         if (!stt)
 305                 return H_TOO_HARD;
 306
 307         ret = kvmppc_ioba_validate(stt, ioba, npages);
 308         if (ret != H_SUCCESS)
 309                 return ret;
 310
 311         /* Check permission bits only to allow userspace poison TCE for debug */
 312         if (tce_value & (TCE_PCI_WRITE | TCE_PCI_READ))
 313                 return H_PARAMETER;
 314
 315         for (i = 0; i < npages; ++i, ioba += (1ULL << stt->page_shift))
 316                 kvmppc_tce_put(stt, ioba >> stt->page_shift, tce_value);
 317
 318         return H_SUCCESS;
 319 }
 320 EXPORT_SYMBOL_GPL(kvmppc_h_stuff_tce);
 321
 322 long kvmppc_h_get_tce(struct kvm_vcpu *vcpu, unsigned long liobn,
 323                       unsigned long ioba)
 324 {
 325         struct kvmppc_spapr_tce_table *stt = kvmppc_find_table(vcpu, liobn);
 326         long ret;
 327         unsigned long idx;
 328         struct page *page;
 329         u64 *tbl;
 330
 331         if (!stt)
 332                 return H_TOO_HARD;
 333
 334         ret = kvmppc_ioba_validate(stt, ioba, 1);
 335         if (ret != H_SUCCESS)
 336                 return ret;
 337
 338         idx = ioba >> stt->page_shift;
 339         page = stt->pages[idx / TCES_PER_PAGE];
 340         tbl = (u64 *)page_address(page);
 341
 342         vcpu->arch.gpr[4] = tbl[idx % TCES_PER_PAGE];
 343
 344         return H_SUCCESS;
 345 }
 346 EXPORT_SYMBOL_GPL(kvmppc_h_get_tce);
 347
 348 #endif /* KVM_BOOK3S_HV_POSSIBLE */