OSCL-LXR linux-6.0.1/​arch/​arm64/​kvm/​hyp/​nvhe/​mem_protect.c	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2020 Google LLC
  * Author: Quentin Perret <qperret@google.com>
  */
 
 #include <linux/kvm_host.h>
 #include <asm/kvm_emulate.h>
 #include <asm/kvm_hyp.h>
 #include <asm/kvm_mmu.h>
 #include <asm/kvm_pgtable.h>
 #include <asm/kvm_pkvm.h>
 #include <asm/stage2_pgtable.h>
 
 #include <hyp/fault.h>
 
 #include <nvhe/gfp.h>
 #include <nvhe/memory.h>
 #include <nvhe/mem_protect.h>
 #include <nvhe/mm.h>
 
 #define KVM_HOST_S2_FLAGS (KVM_PGTABLE_S2_NOFWB | KVM_PGTABLE_S2_IDMAP)
 
 extern unsigned long hyp_nr_cpus;
 struct host_kvm host_kvm;
 
 static struct hyp_pool host_s2_pool;
 
 const u8 pkvm_hyp_id = 1;
 
 static void host_lock_component(void)
 {
     hyp_spin_lock(&host_kvm.lock);
 }
 
 static void host_unlock_component(void)
 {
     hyp_spin_unlock(&host_kvm.lock);
 }
 
 static void hyp_lock_component(void)
 {
     hyp_spin_lock(&pkvm_pgd_lock);
 }
 
 static void hyp_unlock_component(void)
 {
     hyp_spin_unlock(&pkvm_pgd_lock);
 }
 
 static void *host_s2_zalloc_pages_exact(size_t size)
 {
     void *addr = hyp_alloc_pages(&host_s2_pool, get_order(size));
 
     hyp_split_page(hyp_virt_to_page(addr));
 
     /*
      * The size of concatenated PGDs is always a power of two of PAGE_SIZE,
      * so there should be no need to free any of the tail pages to make the
      * allocation exact.
      */
     WARN_ON(size != (PAGE_SIZE << get_order(size)));
 
     return addr;
 }
 
 static void *host_s2_zalloc_page(void *pool)
 {
     return hyp_alloc_pages(pool, 0);
 }
 
 static void host_s2_get_page(void *addr)
 {
     hyp_get_page(&host_s2_pool, addr);
 }
 
 static void host_s2_put_page(void *addr)
 {
     hyp_put_page(&host_s2_pool, addr);
 }
 
 static int prepare_s2_pool(void *pgt_pool_base)
 {
     unsigned long nr_pages, pfn;
     int ret;
 
     pfn = hyp_virt_to_pfn(pgt_pool_base);
     nr_pages = host_s2_pgtable_pages();
     ret = hyp_pool_init(&host_s2_pool, pfn, nr_pages, 0);
     if (ret)
         return ret;
 
     host_kvm.mm_ops = (struct kvm_pgtable_mm_ops) {
         .zalloc_pages_exact = host_s2_zalloc_pages_exact,
         .zalloc_page = host_s2_zalloc_page,
         .phys_to_virt = hyp_phys_to_virt,
         .virt_to_phys = hyp_virt_to_phys,
         .page_count = hyp_page_count,
         .get_page = host_s2_get_page,
         .put_page = host_s2_put_page,
     };
 
     return 0;
 }
 
 static void prepare_host_vtcr(void)
 {
     u32 parange, phys_shift;
 
     /* The host stage 2 is id-mapped, so use parange for T0SZ */
     parange = kvm_get_parange(id_aa64mmfr0_el1_sys_val);
     phys_shift = id_aa64mmfr0_parange_to_phys_shift(parange);
 
     host_kvm.arch.vtcr = kvm_get_vtcr(id_aa64mmfr0_el1_sys_val,
                       id_aa64mmfr1_el1_sys_val, phys_shift);
 }
 
 static bool host_stage2_force_pte_cb(u64 addr, u64 end, enum kvm_pgtable_prot prot);
 
 int kvm_host_prepare_stage2(void *pgt_pool_base)
 {
     struct kvm_s2_mmu *mmu = &host_kvm.arch.mmu;
     int ret;
 
     prepare_host_vtcr();
     hyp_spin_lock_init(&host_kvm.lock);
     mmu->arch = &host_kvm.arch;
 
     ret = prepare_s2_pool(pgt_pool_base);
     if (ret)
         return ret;
 
     ret = __kvm_pgtable_stage2_init(&host_kvm.pgt, mmu,
                     &host_kvm.mm_ops, KVM_HOST_S2_FLAGS,
                     host_stage2_force_pte_cb);
     if (ret)
         return ret;
 
     mmu->pgd_phys = __hyp_pa(host_kvm.pgt.pgd);
     mmu->pgt = &host_kvm.pgt;
     atomic64_set(&mmu->vmid.id, 0);
 
     return 0;
 }
 
 int __pkvm_prot_finalize(void)
 {
     struct kvm_s2_mmu *mmu = &host_kvm.arch.mmu;
     struct kvm_nvhe_init_params *params = this_cpu_ptr(&kvm_init_params);
 
     if (params->hcr_el2 & HCR_VM)
         return -EPERM;
 
     params->vttbr = kvm_get_vttbr(mmu);
     params->vtcr = host_kvm.arch.vtcr;
     params->hcr_el2 |= HCR_VM;
     kvm_flush_dcache_to_poc(params, sizeof(*params));
 
     write_sysreg(params->hcr_el2, hcr_el2);
     __load_stage2(&host_kvm.arch.mmu, &host_kvm.arch);
 
     /*
      * Make sure to have an ISB before the TLB maintenance below but only
      * when __load_stage2() doesn't include one already.
      */
     asm(ALTERNATIVE("isb", "nop", ARM64_WORKAROUND_SPECULATIVE_AT));
 
     /* Invalidate stale HCR bits that may be cached in TLBs */
     __tlbi(vmalls12e1);
     dsb(nsh);
     isb();
 
     return 0;
 }
 
 static int host_stage2_unmap_dev_all(void)
 {
     struct kvm_pgtable *pgt = &host_kvm.pgt;
     struct memblock_region *reg;
     u64 addr = 0;
     int i, ret;
 
     /* Unmap all non-memory regions to recycle the pages */
     for (i = 0; i < hyp_memblock_nr; i++, addr = reg->base + reg->size) {
         reg = &hyp_memory[i];
         ret = kvm_pgtable_stage2_unmap(pgt, addr, reg->base - addr);
         if (ret)
             return ret;
     }
     return kvm_pgtable_stage2_unmap(pgt, addr, BIT(pgt->ia_bits) - addr);
 }
 
 struct kvm_mem_range {
     u64 start;
     u64 end;
 };
 
 static bool find_mem_range(phys_addr_t addr, struct kvm_mem_range *range)
 {
     int cur, left = 0, right = hyp_memblock_nr;
     struct memblock_region *reg;
     phys_addr_t end;
 
     range->start = 0;
     range->end = ULONG_MAX;
 
     /* The list of memblock regions is sorted, binary search it */
     while (left < right) {
         cur = (left + right) >> 1;
         reg = &hyp_memory[cur];
         end = reg->base + reg->size;
         if (addr < reg->base) {
             right = cur;
             range->end = reg->base;
         } else if (addr >= end) {
             left = cur + 1;
             range->start = end;
         } else {
             range->start = reg->base;
             range->end = end;
             return true;
         }
     }
 
     return false;
 }
 
 bool addr_is_memory(phys_addr_t phys)
 {
     struct kvm_mem_range range;
 
     return find_mem_range(phys, &range);
 }
 
 static bool is_in_mem_range(u64 addr, struct kvm_mem_range *range)
 {
     return range->start <= addr && addr < range->end;
 }
 
 static bool range_is_memory(u64 start, u64 end)
 {
     struct kvm_mem_range r;
 
     if (!find_mem_range(start, &r))
         return false;
 
     return is_in_mem_range(end - 1, &r);
 }
 
 static inline int __host_stage2_idmap(u64 start, u64 end,
                       enum kvm_pgtable_prot prot)
 {
     return kvm_pgtable_stage2_map(&host_kvm.pgt, start, end - start, start,
                       prot, &host_s2_pool);
 }
 
 /*
  * The pool has been provided with enough pages to cover all of memory with
  * page granularity, but it is difficult to know how much of the MMIO range
  * we will need to cover upfront, so we may need to 'recycle' the pages if we
  * run out.
  */
 #define host_stage2_try(fn, ...)                    \
     ({                              \
         int __ret;                      \
         hyp_assert_lock_held(&host_kvm.lock);           \
         __ret = fn(__VA_ARGS__);                \
         if (__ret == -ENOMEM) {                 \
             __ret = host_stage2_unmap_dev_all();        \
             if (!__ret)                 \
                 __ret = fn(__VA_ARGS__);        \
         }                           \
         __ret;                          \
      })
 
 static inline bool range_included(struct kvm_mem_range *child,
                   struct kvm_mem_range *parent)
 {
     return parent->start <= child->start && child->end <= parent->end;
 }
 
 static int host_stage2_adjust_range(u64 addr, struct kvm_mem_range *range)
 {
     struct kvm_mem_range cur;
     kvm_pte_t pte;
     u32 level;
     int ret;
 
     hyp_assert_lock_held(&host_kvm.lock);
     ret = kvm_pgtable_get_leaf(&host_kvm.pgt, addr, &pte, &level);
     if (ret)
         return ret;
 
     if (kvm_pte_valid(pte))
         return -EAGAIN;
 
     if (pte)
         return -EPERM;
 
     do {
         u64 granule = kvm_granule_size(level);
         cur.start = ALIGN_DOWN(addr, granule);
         cur.end = cur.start + granule;
         level++;
     } while ((level < KVM_PGTABLE_MAX_LEVELS) &&
             !(kvm_level_supports_block_mapping(level) &&
               range_included(&cur, range)));
 
     *range = cur;
 
     return 0;
 }
 
 int host_stage2_idmap_locked(phys_addr_t addr, u64 size,
                  enum kvm_pgtable_prot prot)
 {
     return host_stage2_try(__host_stage2_idmap, addr, addr + size, prot);
 }
 
 int host_stage2_set_owner_locked(phys_addr_t addr, u64 size, u8 owner_id)
 {
     return host_stage2_try(kvm_pgtable_stage2_set_owner, &host_kvm.pgt,
                    addr, size, &host_s2_pool, owner_id);
 }
 
 static bool host_stage2_force_pte_cb(u64 addr, u64 end, enum kvm_pgtable_prot prot)
 {
     /*
      * Block mappings must be used with care in the host stage-2 as a
      * kvm_pgtable_stage2_map() operation targeting a page in the range of
      * an existing block will delete the block under the assumption that
      * mappings in the rest of the block range can always be rebuilt lazily.
      * That assumption is correct for the host stage-2 with RWX mappings
      * targeting memory or RW mappings targeting MMIO ranges (see
      * host_stage2_idmap() below which implements some of the host memory
      * abort logic). However, this is not safe for any other mappings where
      * the host stage-2 page-table is in fact the only place where this
      * state is stored. In all those cases, it is safer to use page-level
      * mappings, hence avoiding to lose the state because of side-effects in
      * kvm_pgtable_stage2_map().
      */
     if (range_is_memory(addr, end))
         return prot != PKVM_HOST_MEM_PROT;
     else
         return prot != PKVM_HOST_MMIO_PROT;
 }
 
 static int host_stage2_idmap(u64 addr)
 {
     struct kvm_mem_range range;
     bool is_memory = find_mem_range(addr, &range);
     enum kvm_pgtable_prot prot;
     int ret;
 
     prot = is_memory ? PKVM_HOST_MEM_PROT : PKVM_HOST_MMIO_PROT;
 
     host_lock_component();
     ret = host_stage2_adjust_range(addr, &range);
     if (ret)
         goto unlock;
 
     ret = host_stage2_idmap_locked(range.start, range.end - range.start, prot);
 unlock:
     host_unlock_component();
 
     return ret;
 }
 
 void handle_host_mem_abort(struct kvm_cpu_context *host_ctxt)
 {
     struct kvm_vcpu_fault_info fault;
     u64 esr, addr;
     int ret = 0;
 
     esr = read_sysreg_el2(SYS_ESR);
     BUG_ON(!__get_fault_info(esr, &fault));
 
     addr = (fault.hpfar_el2 & HPFAR_MASK) << 8;
     ret = host_stage2_idmap(addr);
     BUG_ON(ret && ret != -EAGAIN);
 }
 
 /* This corresponds to locking order */
 enum pkvm_component_id {
     PKVM_ID_HOST,
     PKVM_ID_HYP,
 };
 
 struct pkvm_mem_transition {
     u64             nr_pages;
 
     struct {
         enum pkvm_component_id  id;
         /* Address in the initiator's address space */
         u64         addr;
 
         union {
             struct {
                 /* Address in the completer's address space */
                 u64 completer_addr;
             } host;
         };
     } initiator;
 
     struct {
         enum pkvm_component_id  id;
     } completer;
 };
 
 struct pkvm_mem_share {
     const struct pkvm_mem_transition    tx;
     const enum kvm_pgtable_prot     completer_prot;
 };
 
 struct check_walk_data {
     enum pkvm_page_state    desired;
     enum pkvm_page_state    (*get_page_state)(kvm_pte_t pte);
 };
 
 static int __check_page_state_visitor(u64 addr, u64 end, u32 level,
                       kvm_pte_t *ptep,
                       enum kvm_pgtable_walk_flags flag,
                       void * const arg)
 {
     struct check_walk_data *d = arg;
     kvm_pte_t pte = *ptep;
 
     if (kvm_pte_valid(pte) && !addr_is_memory(kvm_pte_to_phys(pte)))
         return -EINVAL;
 
     return d->get_page_state(pte) == d->desired ? 0 : -EPERM;
 }
 
 static int check_page_state_range(struct kvm_pgtable *pgt, u64 addr, u64 size,
                   struct check_walk_data *data)
 {
     struct kvm_pgtable_walker walker = {
         .cb = __check_page_state_visitor,
         .arg    = data,
         .flags  = KVM_PGTABLE_WALK_LEAF,
     };
 
     return kvm_pgtable_walk(pgt, addr, size, &walker);
 }
 
 static enum pkvm_page_state host_get_page_state(kvm_pte_t pte)
 {
     if (!kvm_pte_valid(pte) && pte)
         return PKVM_NOPAGE;
 
     return pkvm_getstate(kvm_pgtable_stage2_pte_prot(pte));
 }
 
 static int __host_check_page_state_range(u64 addr, u64 size,
                      enum pkvm_page_state state)
 {
     struct check_walk_data d = {
         .desired    = state,
         .get_page_state = host_get_page_state,
     };
 
     hyp_assert_lock_held(&host_kvm.lock);
     return check_page_state_range(&host_kvm.pgt, addr, size, &d);
 }
 
 static int __host_set_page_state_range(u64 addr, u64 size,
                        enum pkvm_page_state state)
 {
     enum kvm_pgtable_prot prot = pkvm_mkstate(PKVM_HOST_MEM_PROT, state);
 
     return host_stage2_idmap_locked(addr, size, prot);
 }
 
 static int host_request_owned_transition(u64 *completer_addr,
                      const struct pkvm_mem_transition *tx)
 {
     u64 size = tx->nr_pages * PAGE_SIZE;
     u64 addr = tx->initiator.addr;
 
     *completer_addr = tx->initiator.host.completer_addr;
     return __host_check_page_state_range(addr, size, PKVM_PAGE_OWNED);
 }
 
 static int host_request_unshare(u64 *completer_addr,
                 const struct pkvm_mem_transition *tx)
 {
     u64 size = tx->nr_pages * PAGE_SIZE;
     u64 addr = tx->initiator.addr;
 
     *completer_addr = tx->initiator.host.completer_addr;
     return __host_check_page_state_range(addr, size, PKVM_PAGE_SHARED_OWNED);
 }
 
 static int host_initiate_share(u64 *completer_addr,
                    const struct pkvm_mem_transition *tx)
 {
     u64 size = tx->nr_pages * PAGE_SIZE;
     u64 addr = tx->initiator.addr;
 
     *completer_addr = tx->initiator.host.completer_addr;
     return __host_set_page_state_range(addr, size, PKVM_PAGE_SHARED_OWNED);
 }
 
 static int host_initiate_unshare(u64 *completer_addr,
                  const struct pkvm_mem_transition *tx)
 {
     u64 size = tx->nr_pages * PAGE_SIZE;
     u64 addr = tx->initiator.addr;
 
     *completer_addr = tx->initiator.host.completer_addr;
     return __host_set_page_state_range(addr, size, PKVM_PAGE_OWNED);
 }
 
 static enum pkvm_page_state hyp_get_page_state(kvm_pte_t pte)
 {
     if (!kvm_pte_valid(pte))
         return PKVM_NOPAGE;
 
     return pkvm_getstate(kvm_pgtable_stage2_pte_prot(pte));
 }
 
 static int __hyp_check_page_state_range(u64 addr, u64 size,
                     enum pkvm_page_state state)
 {
     struct check_walk_data d = {
         .desired    = state,
         .get_page_state = hyp_get_page_state,
     };
 
     hyp_assert_lock_held(&pkvm_pgd_lock);
     return check_page_state_range(&pkvm_pgtable, addr, size, &d);
 }
 
 static bool __hyp_ack_skip_pgtable_check(const struct pkvm_mem_transition *tx)
 {
     return !(IS_ENABLED(CONFIG_NVHE_EL2_DEBUG) ||
          tx->initiator.id != PKVM_ID_HOST);
 }
 
 static int hyp_ack_share(u64 addr, const struct pkvm_mem_transition *tx,
              enum kvm_pgtable_prot perms)
 {
     u64 size = tx->nr_pages * PAGE_SIZE;
 
     if (perms != PAGE_HYP)
         return -EPERM;
 
     if (__hyp_ack_skip_pgtable_check(tx))
         return 0;
 
     return __hyp_check_page_state_range(addr, size, PKVM_NOPAGE);
 }
 
 static int hyp_ack_unshare(u64 addr, const struct pkvm_mem_transition *tx)
 {
     u64 size = tx->nr_pages * PAGE_SIZE;
 
     if (__hyp_ack_skip_pgtable_check(tx))
         return 0;
 
     return __hyp_check_page_state_range(addr, size,
                         PKVM_PAGE_SHARED_BORROWED);
 }
 
 static int hyp_complete_share(u64 addr, const struct pkvm_mem_transition *tx,
                   enum kvm_pgtable_prot perms)
 {
     void *start = (void *)addr, *end = start + (tx->nr_pages * PAGE_SIZE);
     enum kvm_pgtable_prot prot;
 
     prot = pkvm_mkstate(perms, PKVM_PAGE_SHARED_BORROWED);
     return pkvm_create_mappings_locked(start, end, prot);
 }
 
 static int hyp_complete_unshare(u64 addr, const struct pkvm_mem_transition *tx)
 {
     u64 size = tx->nr_pages * PAGE_SIZE;
     int ret = kvm_pgtable_hyp_unmap(&pkvm_pgtable, addr, size);
 
     return (ret != size) ? -EFAULT : 0;
 }
 
 static int check_share(struct pkvm_mem_share *share)
 {
     const struct pkvm_mem_transition *tx = &share->tx;
     u64 completer_addr;
     int ret;
 
     switch (tx->initiator.id) {
     case PKVM_ID_HOST:
         ret = host_request_owned_transition(&completer_addr, tx);
         break;
     default:
         ret = -EINVAL;
     }
 
     if (ret)
         return ret;
 
     switch (tx->completer.id) {
     case PKVM_ID_HYP:
         ret = hyp_ack_share(completer_addr, tx, share->completer_prot);
         break;
     default:
         ret = -EINVAL;
     }
 
     return ret;
 }
 
 static int __do_share(struct pkvm_mem_share *share)
 {
     const struct pkvm_mem_transition *tx = &share->tx;
     u64 completer_addr;
     int ret;
 
     switch (tx->initiator.id) {
     case PKVM_ID_HOST:
         ret = host_initiate_share(&completer_addr, tx);
         break;
     default:
         ret = -EINVAL;
     }
 
     if (ret)
         return ret;
 
     switch (tx->completer.id) {
     case PKVM_ID_HYP:
         ret = hyp_complete_share(completer_addr, tx, share->completer_prot);
         break;
     default:
         ret = -EINVAL;
     }
 
     return ret;
 }
 
 /*
  * do_share():
  *
  * The page owner grants access to another component with a given set
  * of permissions.
  *
  * Initiator: OWNED => SHARED_OWNED
  * Completer: NOPAGE    => SHARED_BORROWED
  */
 static int do_share(struct pkvm_mem_share *share)
 {
     int ret;
 
     ret = check_share(share);
     if (ret)
         return ret;
 
     return WARN_ON(__do_share(share));
 }
 
 static int check_unshare(struct pkvm_mem_share *share)
 {
     const struct pkvm_mem_transition *tx = &share->tx;
     u64 completer_addr;
     int ret;
 
     switch (tx->initiator.id) {
     case PKVM_ID_HOST:
         ret = host_request_unshare(&completer_addr, tx);
         break;
     default:
         ret = -EINVAL;
     }
 
     if (ret)
         return ret;
 
     switch (tx->completer.id) {
     case PKVM_ID_HYP:
         ret = hyp_ack_unshare(completer_addr, tx);
         break;
     default:
         ret = -EINVAL;
     }
 
     return ret;
 }
 
 static int __do_unshare(struct pkvm_mem_share *share)
 {
     const struct pkvm_mem_transition *tx = &share->tx;
     u64 completer_addr;
     int ret;
 
     switch (tx->initiator.id) {
     case PKVM_ID_HOST:
         ret = host_initiate_unshare(&completer_addr, tx);
         break;
     default:
         ret = -EINVAL;
     }
 
     if (ret)
         return ret;
 
     switch (tx->completer.id) {
     case PKVM_ID_HYP:
         ret = hyp_complete_unshare(completer_addr, tx);
         break;
     default:
         ret = -EINVAL;
     }
 
     return ret;
 }
 
 /*
  * do_unshare():
  *
  * The page owner revokes access from another component for a range of
  * pages which were previously shared using do_share().
  *
  * Initiator: SHARED_OWNED  => OWNED
  * Completer: SHARED_BORROWED   => NOPAGE
  */
 static int do_unshare(struct pkvm_mem_share *share)
 {
     int ret;
 
     ret = check_unshare(share);
     if (ret)
         return ret;
 
     return WARN_ON(__do_unshare(share));
 }
 
 int __pkvm_host_share_hyp(u64 pfn)
 {
     int ret;
     u64 host_addr = hyp_pfn_to_phys(pfn);
     u64 hyp_addr = (u64)__hyp_va(host_addr);
     struct pkvm_mem_share share = {
         .tx = {
             .nr_pages   = 1,
             .initiator  = {
                 .id = PKVM_ID_HOST,
                 .addr   = host_addr,
                 .host   = {
                     .completer_addr = hyp_addr,
                 },
             },
             .completer  = {
                 .id = PKVM_ID_HYP,
             },
         },
         .completer_prot = PAGE_HYP,
     };
 
     host_lock_component();
     hyp_lock_component();
 
     ret = do_share(&share);
 
     hyp_unlock_component();
     host_unlock_component();
 
     return ret;
 }
 
 int __pkvm_host_unshare_hyp(u64 pfn)
 {
     int ret;
     u64 host_addr = hyp_pfn_to_phys(pfn);
     u64 hyp_addr = (u64)__hyp_va(host_addr);
     struct pkvm_mem_share share = {
         .tx = {
             .nr_pages   = 1,
             .initiator  = {
                 .id = PKVM_ID_HOST,
                 .addr   = host_addr,
                 .host   = {
                     .completer_addr = hyp_addr,
                 },
             },
             .completer  = {
                 .id = PKVM_ID_HYP,
             },
         },
         .completer_prot = PAGE_HYP,
     };
 
     host_lock_component();
     hyp_lock_component();
 
     ret = do_unshare(&share);
 
     hyp_unlock_component();
     host_unlock_component();
 
     return ret;
 }

This page was automatically generated by the 2.1.0 LXR engine. The LXR team