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/book3s/64/mmu-hash.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
  43 #define TCES_PER_PAGE   (PAGE_SIZE / sizeof(u64))
  44
  45 /*
  46  * Finds a TCE table descriptor by LIOBN.
  47  *
  48  * WARNING: This will be called in real or virtual mode on HV KVM and virtual
  49  *          mode on PR KVM
  50  */
  51 struct kvmppc_spapr_tce_table *kvmppc_find_table(struct kvm_vcpu *vcpu,
  52                 unsigned long liobn)
  53 {
  54         struct kvm *kvm = vcpu->kvm;
  55         struct kvmppc_spapr_tce_table *stt;
  56
  57         list_for_each_entry_lockless(stt, &kvm->arch.spapr_tce_tables, list)
  58                 if (stt->liobn == liobn)
  59                         return stt;
  60
  61         return NULL;
  62 }
  63 EXPORT_SYMBOL_GPL(kvmppc_find_table);
  64
  65 /*
  66  * Validates IO address.
  67  *
  68  * WARNING: This will be called in real-mode on HV KVM and virtual
  69  *          mode on PR KVM
  70  */
  71 long kvmppc_ioba_validate(struct kvmppc_spapr_tce_table *stt,
  72                 unsigned long ioba, unsigned long npages)
  73 {
  74         unsigned long mask = (1ULL << stt->page_shift) - 1;
  75         unsigned long idx = ioba >> stt->page_shift;
  76
  77         if ((ioba & mask) || (idx < stt->offset) ||
  78                         (idx - stt->offset + npages > stt->size) ||
  79                         (idx + npages < idx))
  80                 return H_PARAMETER;
  81
  82         return H_SUCCESS;
  83 }
  84 EXPORT_SYMBOL_GPL(kvmppc_ioba_validate);
  85
  86 /*
  87  * Validates TCE address.
  88  * At the moment flags and page mask are validated.
  89  * As the host kernel does not access those addresses (just puts them
  90  * to the table and user space is supposed to process them), we can skip
  91  * checking other things (such as TCE is a guest RAM address or the page
  92  * was actually allocated).
  93  *
  94  * WARNING: This will be called in real-mode on HV KVM and virtual
  95  *          mode on PR KVM
  96  */
  97 long kvmppc_tce_validate(struct kvmppc_spapr_tce_table *stt, unsigned long tce)
  98 {
  99         unsigned long page_mask = ~((1ULL << stt->page_shift) - 1);
 100         unsigned long mask = ~(page_mask | TCE_PCI_WRITE | TCE_PCI_READ);
 101
 102         if (tce & mask)
 103                 return H_PARAMETER;
 104
 105         return H_SUCCESS;
 106 }
 107 EXPORT_SYMBOL_GPL(kvmppc_tce_validate);
 108
 109 /* Note on the use of page_address() in real mode,
 110  *
 111  * It is safe to use page_address() in real mode on ppc64 because
 112  * page_address() is always defined as lowmem_page_address()
 113  * which returns __va(PFN_PHYS(page_to_pfn(page))) which is arithmetic
 114  * operation and does not access page struct.
 115  *
 116  * Theoretically page_address() could be defined different
 117  * but either WANT_PAGE_VIRTUAL or HASHED_PAGE_VIRTUAL
 118  * would have to be enabled.
 119  * WANT_PAGE_VIRTUAL is never enabled on ppc32/ppc64,
 120  * HASHED_PAGE_VIRTUAL could be enabled for ppc32 only and only
 121  * if CONFIG_HIGHMEM is defined. As CONFIG_SPARSEMEM_VMEMMAP
 122  * is not expected to be enabled on ppc32, page_address()
 123  * is safe for ppc32 as well.
 124  *
 125  * WARNING: This will be called in real-mode on HV KVM and virtual
 126  *          mode on PR KVM
 127  */
 128 static u64 *kvmppc_page_address(struct page *page)
 129 {
 130 #if defined(HASHED_PAGE_VIRTUAL) || defined(WANT_PAGE_VIRTUAL)
 131 #error TODO: fix to avoid page_address() here
 132 #endif
 133         return (u64 *) page_address(page);
 134 }
 135
 136 /*
 137  * Handles TCE requests for emulated devices.
 138  * Puts guest TCE values to the table and expects user space to convert them.
 139  * Called in both real and virtual modes.
 140  * Cannot fail so kvmppc_tce_validate must be called before it.
 141  *
 142  * WARNING: This will be called in real-mode on HV KVM and virtual
 143  *          mode on PR KVM
 144  */
 145 void kvmppc_tce_put(struct kvmppc_spapr_tce_table *stt,
 146                 unsigned long idx, unsigned long tce)
 147 {
 148         struct page *page;
 149         u64 *tbl;
 150
 151         idx -= stt->offset;
 152         page = stt->pages[idx / TCES_PER_PAGE];
 153         tbl = kvmppc_page_address(page);
 154
 155         tbl[idx % TCES_PER_PAGE] = tce;
 156 }
 157 EXPORT_SYMBOL_GPL(kvmppc_tce_put);
 158
 159 long kvmppc_gpa_to_ua(struct kvm *kvm, unsigned long gpa,
 160                 unsigned long *ua, unsigned long **prmap)
 161 {
 162         unsigned long gfn = gpa >> PAGE_SHIFT;
 163         struct kvm_memory_slot *memslot;
 164
 165         memslot = search_memslots(kvm_memslots(kvm), gfn);
 166         if (!memslot)
 167                 return -EINVAL;
 168
 169         *ua = __gfn_to_hva_memslot(memslot, gfn) |
 170                 (gpa & ~(PAGE_MASK | TCE_PCI_READ | TCE_PCI_WRITE));
 171
 172 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
 173         if (prmap)
 174                 *prmap = &memslot->arch.rmap[gfn - memslot->base_gfn];
 175 #endif
 176
 177         return 0;
 178 }
 179 EXPORT_SYMBOL_GPL(kvmppc_gpa_to_ua);
 180
 181 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
 182 long kvmppc_rm_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn,
 183                 unsigned long ioba, unsigned long tce)
 184 {
 185         struct kvmppc_spapr_tce_table *stt = kvmppc_find_table(vcpu, liobn);
 186         long ret;
 187
 188         /* udbg_printf("H_PUT_TCE(): liobn=0x%lx ioba=0x%lx, tce=0x%lx\n", */
 189         /*          liobn, ioba, tce); */
 190
 191         if (!stt)
 192                 return H_TOO_HARD;
 193
 194         ret = kvmppc_ioba_validate(stt, ioba, 1);
 195         if (ret != H_SUCCESS)
 196                 return ret;
 197
 198         ret = kvmppc_tce_validate(stt, tce);
 199         if (ret != H_SUCCESS)
 200                 return ret;
 201
 202         kvmppc_tce_put(stt, ioba >> stt->page_shift, tce);
 203
 204         return H_SUCCESS;
 205 }
 206
 207 static long kvmppc_rm_ua_to_hpa(struct kvm_vcpu *vcpu,
 208                 unsigned long ua, unsigned long *phpa)
 209 {
 210         pte_t *ptep, pte;
 211         unsigned shift = 0;
 212
 213         ptep = __find_linux_pte_or_hugepte(vcpu->arch.pgdir, ua, NULL, &shift);
 214         if (!ptep || !pte_present(*ptep))
 215                 return -ENXIO;
 216         pte = *ptep;
 217
 218         if (!shift)
 219                 shift = PAGE_SHIFT;
 220
 221         /* Avoid handling anything potentially complicated in realmode */
 222         if (shift > PAGE_SHIFT)
 223                 return -EAGAIN;
 224
 225         if (!pte_young(pte))
 226                 return -EAGAIN;
 227
 228         *phpa = (pte_pfn(pte) << PAGE_SHIFT) | (ua & ((1ULL << shift) - 1)) |
 229                         (ua & ~PAGE_MASK);
 230
 231         return 0;
 232 }
 233
 234 long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
 235                 unsigned long liobn, unsigned long ioba,
 236                 unsigned long tce_list, unsigned long npages)
 237 {
 238         struct kvmppc_spapr_tce_table *stt;
 239         long i, ret = H_SUCCESS;
 240         unsigned long tces, entry, ua = 0;
 241         unsigned long *rmap = NULL;
 242
 243         stt = kvmppc_find_table(vcpu, liobn);
 244         if (!stt)
 245                 return H_TOO_HARD;
 246
 247         entry = ioba >> stt->page_shift;
 248         /*
 249          * The spec says that the maximum size of the list is 512 TCEs
 250          * so the whole table addressed resides in 4K page
 251          */
 252         if (npages > 512)
 253                 return H_PARAMETER;
 254
 255         if (tce_list & (SZ_4K - 1))
 256                 return H_PARAMETER;
 257
 258         ret = kvmppc_ioba_validate(stt, ioba, npages);
 259         if (ret != H_SUCCESS)
 260                 return ret;
 261
 262         if (kvmppc_gpa_to_ua(vcpu->kvm, tce_list, &ua, &rmap))
 263                 return H_TOO_HARD;
 264
 265         rmap = (void *) vmalloc_to_phys(rmap);
 266
 267         /*
 268          * Synchronize with the MMU notifier callbacks in
 269          * book3s_64_mmu_hv.c (kvm_unmap_hva_hv etc.).
 270          * While we have the rmap lock, code running on other CPUs
 271          * cannot finish unmapping the host real page that backs
 272          * this guest real page, so we are OK to access the host
 273          * real page.
 274          */
 275         lock_rmap(rmap);
 276         if (kvmppc_rm_ua_to_hpa(vcpu, ua, &tces)) {
 277                 ret = H_TOO_HARD;
 278                 goto unlock_exit;
 279         }
 280
 281         for (i = 0; i < npages; ++i) {
 282                 unsigned long tce = be64_to_cpu(((u64 *)tces)[i]);
 283
 284                 ret = kvmppc_tce_validate(stt, tce);
 285                 if (ret != H_SUCCESS)
 286                         goto unlock_exit;
 287
 288                 kvmppc_tce_put(stt, entry + i, tce);
 289         }
 290
 291 unlock_exit:
 292         unlock_rmap(rmap);
 293
 294         return ret;
 295 }
 296
 297 long kvmppc_rm_h_stuff_tce(struct kvm_vcpu *vcpu,
 298                 unsigned long liobn, unsigned long ioba,
 299                 unsigned long tce_value, unsigned long npages)
 300 {
 301         struct kvmppc_spapr_tce_table *stt;
 302         long i, ret;
 303
 304         stt = kvmppc_find_table(vcpu, liobn);
 305         if (!stt)
 306                 return H_TOO_HARD;
 307
 308         ret = kvmppc_ioba_validate(stt, ioba, npages);
 309         if (ret != H_SUCCESS)
 310                 return ret;
 311
 312         /* Check permission bits only to allow userspace poison TCE for debug */
 313         if (tce_value & (TCE_PCI_WRITE | TCE_PCI_READ))
 314                 return H_PARAMETER;
 315
 316         for (i = 0; i < npages; ++i, ioba += (1ULL << stt->page_shift))
 317                 kvmppc_tce_put(stt, ioba >> stt->page_shift, tce_value);
 318
 319         return H_SUCCESS;
 320 }
 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) - stt->offset;
 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 */