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 #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 < stt->offset) ||
  79                         (idx - stt->offset + npages > stt->size) ||
  80                         (idx + npages < idx))
  81                 return H_PARAMETER;
  82
  83         return H_SUCCESS;
  84 }
  85 EXPORT_SYMBOL_GPL(kvmppc_ioba_validate);
  86
  87 /*
  88  * Validates TCE address.
  89  * At the moment flags and page mask are validated.
  90  * As the host kernel does not access those addresses (just puts them
  91  * to the table and user space is supposed to process them), we can skip
  92  * checking other things (such as TCE is a guest RAM address or the page
  93  * was actually allocated).
  94  *
  95  * WARNING: This will be called in real-mode on HV KVM and virtual
  96  *          mode on PR KVM
  97  */
  98 long kvmppc_tce_validate(struct kvmppc_spapr_tce_table *stt, unsigned long tce)
  99 {
 100         unsigned long page_mask = ~((1ULL << stt->page_shift) - 1);
 101         unsigned long mask = ~(page_mask | TCE_PCI_WRITE | TCE_PCI_READ);
 102
 103         if (tce & mask)
 104                 return H_PARAMETER;
 105
 106         return H_SUCCESS;
 107 }
 108 EXPORT_SYMBOL_GPL(kvmppc_tce_validate);
 109
 110 /* Note on the use of page_address() in real mode,
 111  *
 112  * It is safe to use page_address() in real mode on ppc64 because
 113  * page_address() is always defined as lowmem_page_address()
 114  * which returns __va(PFN_PHYS(page_to_pfn(page))) which is arithmetic
 115  * operation and does not access page struct.
 116  *
 117  * Theoretically page_address() could be defined different
 118  * but either WANT_PAGE_VIRTUAL or HASHED_PAGE_VIRTUAL
 119  * would have to be enabled.
 120  * WANT_PAGE_VIRTUAL is never enabled on ppc32/ppc64,
 121  * HASHED_PAGE_VIRTUAL could be enabled for ppc32 only and only
 122  * if CONFIG_HIGHMEM is defined. As CONFIG_SPARSEMEM_VMEMMAP
 123  * is not expected to be enabled on ppc32, page_address()
 124  * is safe for ppc32 as well.
 125  *
 126  * WARNING: This will be called in real-mode on HV KVM and virtual
 127  *          mode on PR KVM
 128  */
 129 static u64 *kvmppc_page_address(struct page *page)
 130 {
 131 #if defined(HASHED_PAGE_VIRTUAL) || defined(WANT_PAGE_VIRTUAL)
 132 #error TODO: fix to avoid page_address() here
 133 #endif
 134         return (u64 *) page_address(page);
 135 }
 136
 137 /*
 138  * Handles TCE requests for emulated devices.
 139  * Puts guest TCE values to the table and expects user space to convert them.
 140  * Called in both real and virtual modes.
 141  * Cannot fail so kvmppc_tce_validate must be called before it.
 142  *
 143  * WARNING: This will be called in real-mode on HV KVM and virtual
 144  *          mode on PR KVM
 145  */
 146 void kvmppc_tce_put(struct kvmppc_spapr_tce_table *stt,
 147                 unsigned long idx, unsigned long tce)
 148 {
 149         struct page *page;
 150         u64 *tbl;
 151
 152         idx -= stt->offset;
 153         page = stt->pages[idx / TCES_PER_PAGE];
 154         tbl = kvmppc_page_address(page);
 155
 156         tbl[idx % TCES_PER_PAGE] = tce;
 157 }
 158 EXPORT_SYMBOL_GPL(kvmppc_tce_put);
 159
 160 long kvmppc_gpa_to_ua(struct kvm *kvm, unsigned long gpa,
 161                 unsigned long *ua, unsigned long **prmap)
 162 {
 163         unsigned long gfn = gpa >> PAGE_SHIFT;
 164         struct kvm_memory_slot *memslot;
 165
 166         memslot = search_memslots(kvm_memslots(kvm), gfn);
 167         if (!memslot)
 168                 return -EINVAL;
 169
 170         *ua = __gfn_to_hva_memslot(memslot, gfn) |
 171                 (gpa & ~(PAGE_MASK | TCE_PCI_READ | TCE_PCI_WRITE));
 172
 173 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
 174         if (prmap)
 175                 *prmap = &memslot->arch.rmap[gfn - memslot->base_gfn];
 176 #endif
 177
 178         return 0;
 179 }
 180 EXPORT_SYMBOL_GPL(kvmppc_gpa_to_ua);
 181
 182 #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
 183 long kvmppc_rm_h_put_tce(struct kvm_vcpu *vcpu, unsigned long liobn,
 184                 unsigned long ioba, unsigned long tce)
 185 {
 186         struct kvmppc_spapr_tce_table *stt = kvmppc_find_table(vcpu, liobn);
 187         long ret;
 188
 189         /* udbg_printf("H_PUT_TCE(): liobn=0x%lx ioba=0x%lx, tce=0x%lx\n", */
 190         /*          liobn, ioba, tce); */
 191
 192         if (!stt)
 193                 return H_TOO_HARD;
 194
 195         ret = kvmppc_ioba_validate(stt, ioba, 1);
 196         if (ret != H_SUCCESS)
 197                 return ret;
 198
 199         ret = kvmppc_tce_validate(stt, tce);
 200         if (ret != H_SUCCESS)
 201                 return ret;
 202
 203         kvmppc_tce_put(stt, ioba >> stt->page_shift, tce);
 204
 205         return H_SUCCESS;
 206 }
 207
 208 static long kvmppc_rm_ua_to_hpa(struct kvm_vcpu *vcpu,
 209                 unsigned long ua, unsigned long *phpa)
 210 {
 211         pte_t *ptep, pte;
 212         unsigned shift = 0;
 213
 214         ptep = __find_linux_pte_or_hugepte(vcpu->arch.pgdir, ua, NULL, &shift);
 215         if (!ptep || !pte_present(*ptep))
 216                 return -ENXIO;
 217         pte = *ptep;
 218
 219         if (!shift)
 220                 shift = PAGE_SHIFT;
 221
 222         /* Avoid handling anything potentially complicated in realmode */
 223         if (shift > PAGE_SHIFT)
 224                 return -EAGAIN;
 225
 226         if (!pte_young(pte))
 227                 return -EAGAIN;
 228
 229         *phpa = (pte_pfn(pte) << PAGE_SHIFT) | (ua & ((1ULL << shift) - 1)) |
 230                         (ua & ~PAGE_MASK);
 231
 232         return 0;
 233 }
 234
 235 long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
 236                 unsigned long liobn, unsigned long ioba,
 237                 unsigned long tce_list, unsigned long npages)
 238 {
 239         struct kvmppc_spapr_tce_table *stt;
 240         long i, ret = H_SUCCESS;
 241         unsigned long tces, entry, ua = 0;
 242         unsigned long *rmap = NULL;
 243
 244         stt = kvmppc_find_table(vcpu, liobn);
 245         if (!stt)
 246                 return H_TOO_HARD;
 247
 248         entry = ioba >> stt->page_shift;
 249         /*
 250          * The spec says that the maximum size of the list is 512 TCEs
 251          * so the whole table addressed resides in 4K page
 252          */
 253         if (npages > 512)
 254                 return H_PARAMETER;
 255
 256         if (tce_list & (SZ_4K - 1))
 257                 return H_PARAMETER;
 258
 259         ret = kvmppc_ioba_validate(stt, ioba, npages);
 260         if (ret != H_SUCCESS)
 261                 return ret;
 262
 263         if (kvmppc_gpa_to_ua(vcpu->kvm, tce_list, &ua, &rmap))
 264                 return H_TOO_HARD;
 265
 266         rmap = (void *) vmalloc_to_phys(rmap);
 267
 268         /*
 269          * Synchronize with the MMU notifier callbacks in
 270          * book3s_64_mmu_hv.c (kvm_unmap_hva_hv etc.).
 271          * While we have the rmap lock, code running on other CPUs
 272          * cannot finish unmapping the host real page that backs
 273          * this guest real page, so we are OK to access the host
 274          * real page.
 275          */
 276         lock_rmap(rmap);
 277         if (kvmppc_rm_ua_to_hpa(vcpu, ua, &tces)) {
 278                 ret = H_TOO_HARD;
 279                 goto unlock_exit;
 280         }
 281
 282         for (i = 0; i < npages; ++i) {
 283                 unsigned long tce = be64_to_cpu(((u64 *)tces)[i]);
 284
 285                 ret = kvmppc_tce_validate(stt, tce);
 286                 if (ret != H_SUCCESS)
 287                         goto unlock_exit;
 288
 289                 kvmppc_tce_put(stt, entry + i, tce);
 290         }
 291
 292 unlock_exit:
 293         unlock_rmap(rmap);
 294
 295         return ret;
 296 }
 297
 298 long kvmppc_rm_h_stuff_tce(struct kvm_vcpu *vcpu,
 299                 unsigned long liobn, unsigned long ioba,
 300                 unsigned long tce_value, unsigned long npages)
 301 {
 302         struct kvmppc_spapr_tce_table *stt;
 303         long i, ret;
 304
 305         stt = kvmppc_find_table(vcpu, liobn);
 306         if (!stt)
 307                 return H_TOO_HARD;
 308
 309         ret = kvmppc_ioba_validate(stt, ioba, npages);
 310         if (ret != H_SUCCESS)
 311                 return ret;
 312
 313         /* Check permission bits only to allow userspace poison TCE for debug */
 314         if (tce_value & (TCE_PCI_WRITE | TCE_PCI_READ))
 315                 return H_PARAMETER;
 316
 317         for (i = 0; i < npages; ++i, ioba += (1ULL << stt->page_shift))
 318                 kvmppc_tce_put(stt, ioba >> stt->page_shift, tce_value);
 319
 320         return H_SUCCESS;
 321 }
 322
 323 long kvmppc_h_get_tce(struct kvm_vcpu *vcpu, unsigned long liobn,
 324                       unsigned long ioba)
 325 {
 326         struct kvmppc_spapr_tce_table *stt = kvmppc_find_table(vcpu, liobn);
 327         long ret;
 328         unsigned long idx;
 329         struct page *page;
 330         u64 *tbl;
 331
 332         if (!stt)
 333                 return H_TOO_HARD;
 334
 335         ret = kvmppc_ioba_validate(stt, ioba, 1);
 336         if (ret != H_SUCCESS)
 337                 return ret;
 338
 339         idx = (ioba >> stt->page_shift) - stt->offset;
 340         page = stt->pages[idx / TCES_PER_PAGE];
 341         tbl = (u64 *)page_address(page);
 342
 343         vcpu->arch.gpr[4] = tbl[idx % TCES_PER_PAGE];
 344
 345         return H_SUCCESS;
 346 }
 347 EXPORT_SYMBOL_GPL(kvmppc_h_get_tce);
 348
 349 #endif /* KVM_BOOK3S_HV_POSSIBLE */