/* * Copyright (C) 2012 - Virtual Open Systems and Columbia University * Author: Christoffer Dall * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License, version 2, as * published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "trace.h" extern char __hyp_idmap_text_start[], __hyp_idmap_text_end[]; static DEFINE_MUTEX(kvm_hyp_pgd_mutex); static void kvm_tlb_flush_vmid(struct kvm *kvm) { kvm_call_hyp(__kvm_tlb_flush_vmid, kvm); } static void kvm_set_pte(pte_t *pte, pte_t new_pte) { pte_val(*pte) = new_pte; /* * flush_pmd_entry just takes a void pointer and cleans the necessary * cache entries, so we can reuse the function for ptes. */ flush_pmd_entry(pte); } static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache, int min, int max) { void *page; BUG_ON(max > KVM_NR_MEM_OBJS); if (cache->nobjs >= min) return 0; while (cache->nobjs < max) { page = (void *)__get_free_page(PGALLOC_GFP); if (!page) return -ENOMEM; cache->objects[cache->nobjs++] = page; } return 0; } static void mmu_free_memory_cache(struct kvm_mmu_memory_cache *mc) { while (mc->nobjs) free_page((unsigned long)mc->objects[--mc->nobjs]); } static void *mmu_memory_cache_alloc(struct kvm_mmu_memory_cache *mc) { void *p; BUG_ON(!mc || !mc->nobjs); p = mc->objects[--mc->nobjs]; return p; } static void free_ptes(pmd_t *pmd, unsigned long addr) { pte_t *pte; unsigned int i; for (i = 0; i < PTRS_PER_PMD; i++, addr += PMD_SIZE) { if (!pmd_none(*pmd) && pmd_table(*pmd)) { pte = pte_offset_kernel(pmd, addr); pte_free_kernel(NULL, pte); } pmd++; } } /** * free_hyp_pmds - free a Hyp-mode level-2 tables and child level-3 tables * * Assumes this is a page table used strictly in Hyp-mode and therefore contains * only mappings in the kernel memory area, which is above PAGE_OFFSET. */ void free_hyp_pmds(void) { pgd_t *pgd; pud_t *pud; pmd_t *pmd; unsigned long addr; mutex_lock(&kvm_hyp_pgd_mutex); for (addr = PAGE_OFFSET; addr != 0; addr += PGDIR_SIZE) { pgd = hyp_pgd + pgd_index(addr); pud = pud_offset(pgd, addr); if (pud_none(*pud)) continue; BUG_ON(pud_bad(*pud)); pmd = pmd_offset(pud, addr); free_ptes(pmd, addr); pmd_free(NULL, pmd); pud_clear(pud); } mutex_unlock(&kvm_hyp_pgd_mutex); } static void create_hyp_pte_mappings(pmd_t *pmd, unsigned long start, unsigned long end) { pte_t *pte; unsigned long addr; struct page *page; for (addr = start & PAGE_MASK; addr < end; addr += PAGE_SIZE) { pte = pte_offset_kernel(pmd, addr); BUG_ON(!virt_addr_valid(addr)); page = virt_to_page(addr); kvm_set_pte(pte, mk_pte(page, PAGE_HYP)); } } static void create_hyp_io_pte_mappings(pmd_t *pmd, unsigned long start, unsigned long end, unsigned long *pfn_base) { pte_t *pte; unsigned long addr; for (addr = start & PAGE_MASK; addr < end; addr += PAGE_SIZE) { pte = pte_offset_kernel(pmd, addr); BUG_ON(pfn_valid(*pfn_base)); kvm_set_pte(pte, pfn_pte(*pfn_base, PAGE_HYP_DEVICE)); (*pfn_base)++; } } static int create_hyp_pmd_mappings(pud_t *pud, unsigned long start, unsigned long end, unsigned long *pfn_base) { pmd_t *pmd; pte_t *pte; unsigned long addr, next; for (addr = start; addr < end; addr = next) { pmd = pmd_offset(pud, addr); BUG_ON(pmd_sect(*pmd)); if (pmd_none(*pmd)) { pte = pte_alloc_one_kernel(NULL, addr); if (!pte) { kvm_err("Cannot allocate Hyp pte\n"); return -ENOMEM; } pmd_populate_kernel(NULL, pmd, pte); } next = pmd_addr_end(addr, end); /* * If pfn_base is NULL, we map kernel pages into HYP with the * virtual address. Otherwise, this is considered an I/O * mapping and we map the physical region starting at * *pfn_base to [start, end[. */ if (!pfn_base) create_hyp_pte_mappings(pmd, addr, next); else create_hyp_io_pte_mappings(pmd, addr, next, pfn_base); } return 0; } static int __create_hyp_mappings(void *from, void *to, unsigned long *pfn_base) { unsigned long start = (unsigned long)from; unsigned long end = (unsigned long)to; pgd_t *pgd; pud_t *pud; pmd_t *pmd; unsigned long addr, next; int err = 0; BUG_ON(start > end); if (start < PAGE_OFFSET) return -EINVAL; mutex_lock(&kvm_hyp_pgd_mutex); for (addr = start; addr < end; addr = next) { pgd = hyp_pgd + pgd_index(addr); pud = pud_offset(pgd, addr); if (pud_none_or_clear_bad(pud)) { pmd = pmd_alloc_one(NULL, addr); if (!pmd) { kvm_err("Cannot allocate Hyp pmd\n"); err = -ENOMEM; goto out; } pud_populate(NULL, pud, pmd); } next = pgd_addr_end(addr, end); err = create_hyp_pmd_mappings(pud, addr, next, pfn_base); if (err) goto out; } out: mutex_unlock(&kvm_hyp_pgd_mutex); return err; } /** * create_hyp_mappings - map a kernel virtual address range in Hyp mode * @from: The virtual kernel start address of the range * @to: The virtual kernel end address of the range (exclusive) * * The same virtual address as the kernel virtual address is also used in * Hyp-mode mapping to the same underlying physical pages. * * Note: Wrapping around zero in the "to" address is not supported. */ int create_hyp_mappings(void *from, void *to) { return __create_hyp_mappings(from, to, NULL); } /** * create_hyp_io_mappings - map a physical IO range in Hyp mode * @from: The virtual HYP start address of the range * @to: The virtual HYP end address of the range (exclusive) * @addr: The physical start address which gets mapped */ int create_hyp_io_mappings(void *from, void *to, phys_addr_t addr) { unsigned long pfn = __phys_to_pfn(addr); return __create_hyp_mappings(from, to, &pfn); } /** * kvm_alloc_stage2_pgd - allocate level-1 table for stage-2 translation. * @kvm: The KVM struct pointer for the VM. * * Allocates the 1st level table only of size defined by S2_PGD_ORDER (can * support either full 40-bit input addresses or limited to 32-bit input * addresses). Clears the allocated pages. * * Note we don't need locking here as this is only called when the VM is * created, which can only be done once. */ int kvm_alloc_stage2_pgd(struct kvm *kvm) { pgd_t *pgd; if (kvm->arch.pgd != NULL) { kvm_err("kvm_arch already initialized?\n"); return -EINVAL; } pgd = (pgd_t *)__get_free_pages(GFP_KERNEL, S2_PGD_ORDER); if (!pgd) return -ENOMEM; /* stage-2 pgd must be aligned to its size */ VM_BUG_ON((unsigned long)pgd & (S2_PGD_SIZE - 1)); memset(pgd, 0, PTRS_PER_S2_PGD * sizeof(pgd_t)); clean_dcache_area(pgd, PTRS_PER_S2_PGD * sizeof(pgd_t)); kvm->arch.pgd = pgd; return 0; } static void clear_pud_entry(pud_t *pud) { pmd_t *pmd_table = pmd_offset(pud, 0); pud_clear(pud); pmd_free(NULL, pmd_table); put_page(virt_to_page(pud)); } static void clear_pmd_entry(pmd_t *pmd) { pte_t *pte_table = pte_offset_kernel(pmd, 0); pmd_clear(pmd); pte_free_kernel(NULL, pte_table); put_page(virt_to_page(pmd)); } static bool pmd_empty(pmd_t *pmd) { struct page *pmd_page = virt_to_page(pmd); return page_count(pmd_page) == 1; } static void clear_pte_entry(pte_t *pte) { if (pte_present(*pte)) { kvm_set_pte(pte, __pte(0)); put_page(virt_to_page(pte)); } } static bool pte_empty(pte_t *pte) { struct page *pte_page = virt_to_page(pte); return page_count(pte_page) == 1; } /** * unmap_stage2_range -- Clear stage2 page table entries to unmap a range * @kvm: The VM pointer * @start: The intermediate physical base address of the range to unmap * @size: The size of the area to unmap * * Clear a range of stage-2 mappings, lowering the various ref-counts. Must * be called while holding mmu_lock (unless for freeing the stage2 pgd before * destroying the VM), otherwise another faulting VCPU may come in and mess * with things behind our backs. */ static void unmap_stage2_range(struct kvm *kvm, phys_addr_t start, u64 size) { pgd_t *pgd; pud_t *pud; pmd_t *pmd; pte_t *pte; phys_addr_t addr = start, end = start + size; u64 range; while (addr < end) { pgd = kvm->arch.pgd + pgd_index(addr); pud = pud_offset(pgd, addr); if (pud_none(*pud)) { addr += PUD_SIZE; continue; } pmd = pmd_offset(pud, addr); if (pmd_none(*pmd)) { addr += PMD_SIZE; continue; } pte = pte_offset_kernel(pmd, addr); clear_pte_entry(pte); range = PAGE_SIZE; /* If we emptied the pte, walk back up the ladder */ if (pte_empty(pte)) { clear_pmd_entry(pmd); range = PMD_SIZE; if (pmd_empty(pmd)) { clear_pud_entry(pud); range = PUD_SIZE; } } addr += range; } } /** * kvm_free_stage2_pgd - free all stage-2 tables * @kvm: The KVM struct pointer for the VM. * * Walks the level-1 page table pointed to by kvm->arch.pgd and frees all * underlying level-2 and level-3 tables before freeing the actual level-1 table * and setting the struct pointer to NULL. * * Note we don't need locking here as this is only called when the VM is * destroyed, which can only be done once. */ void kvm_free_stage2_pgd(struct kvm *kvm) { if (kvm->arch.pgd == NULL) return; unmap_stage2_range(kvm, 0, KVM_PHYS_SIZE); free_pages((unsigned long)kvm->arch.pgd, S2_PGD_ORDER); kvm->arch.pgd = NULL; } static int stage2_set_pte(struct kvm *kvm, struct kvm_mmu_memory_cache *cache, phys_addr_t addr, const pte_t *new_pte, bool iomap) { pgd_t *pgd; pud_t *pud; pmd_t *pmd; pte_t *pte, old_pte; /* Create 2nd stage page table mapping - Level 1 */ pgd = kvm->arch.pgd + pgd_index(addr); pud = pud_offset(pgd, addr); if (pud_none(*pud)) { if (!cache) return 0; /* ignore calls from kvm_set_spte_hva */ pmd = mmu_memory_cache_alloc(cache); pud_populate(NULL, pud, pmd); pmd += pmd_index(addr); get_page(virt_to_page(pud)); } else pmd = pmd_offset(pud, addr); /* Create 2nd stage page table mapping - Level 2 */ if (pmd_none(*pmd)) { if (!cache) return 0; /* ignore calls from kvm_set_spte_hva */ pte = mmu_memory_cache_alloc(cache); clean_pte_table(pte); pmd_populate_kernel(NULL, pmd, pte); pte += pte_index(addr); get_page(virt_to_page(pmd)); } else pte = pte_offset_kernel(pmd, addr); if (iomap && pte_present(*pte)) return -EFAULT; /* Create 2nd stage page table mapping - Level 3 */ old_pte = *pte; kvm_set_pte(pte, *new_pte); if (pte_present(old_pte)) kvm_tlb_flush_vmid(kvm); else get_page(virt_to_page(pte)); return 0; } /** * kvm_phys_addr_ioremap - map a device range to guest IPA * * @kvm: The KVM pointer * @guest_ipa: The IPA at which to insert the mapping * @pa: The physical address of the device * @size: The size of the mapping */ int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa, phys_addr_t pa, unsigned long size) { phys_addr_t addr, end; int ret = 0; unsigned long pfn; struct kvm_mmu_memory_cache cache = { 0, }; end = (guest_ipa + size + PAGE_SIZE - 1) & PAGE_MASK; pfn = __phys_to_pfn(pa); for (addr = guest_ipa; addr < end; addr += PAGE_SIZE) { pte_t pte = pfn_pte(pfn, PAGE_S2_DEVICE | L_PTE_S2_RDWR); ret = mmu_topup_memory_cache(&cache, 2, 2); if (ret) goto out; spin_lock(&kvm->mmu_lock); ret = stage2_set_pte(kvm, &cache, addr, &pte, true); spin_unlock(&kvm->mmu_lock); if (ret) goto out; pfn++; } out: mmu_free_memory_cache(&cache); return ret; } static void coherent_icache_guest_page(struct kvm *kvm, gfn_t gfn) { /* * If we are going to insert an instruction page and the icache is * either VIPT or PIPT, there is a potential problem where the host * (or another VM) may have used the same page as this guest, and we * read incorrect data from the icache. If we're using a PIPT cache, * we can invalidate just that page, but if we are using a VIPT cache * we need to invalidate the entire icache - damn shame - as written * in the ARM ARM (DDI 0406C.b - Page B3-1393). * * VIVT caches are tagged using both the ASID and the VMID and doesn't * need any kind of flushing (DDI 0406C.b - Page B3-1392). */ if (icache_is_pipt()) { unsigned long hva = gfn_to_hva(kvm, gfn); __cpuc_coherent_user_range(hva, hva + PAGE_SIZE); } else if (!icache_is_vivt_asid_tagged()) { /* any kind of VIPT cache */ __flush_icache_all(); } } static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, gfn_t gfn, struct kvm_memory_slot *memslot, unsigned long fault_status) { pte_t new_pte; pfn_t pfn; int ret; bool write_fault, writable; unsigned long mmu_seq; struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache; write_fault = kvm_is_write_fault(kvm_vcpu_get_hsr(vcpu)); if (fault_status == FSC_PERM && !write_fault) { kvm_err("Unexpected L2 read permission error\n"); return -EFAULT; } /* We need minimum second+third level pages */ ret = mmu_topup_memory_cache(memcache, 2, KVM_NR_MEM_OBJS); if (ret) return ret; mmu_seq = vcpu->kvm->mmu_notifier_seq; /* * Ensure the read of mmu_notifier_seq happens before we call * gfn_to_pfn_prot (which calls get_user_pages), so that we don't risk * the page we just got a reference to gets unmapped before we have a * chance to grab the mmu_lock, which ensure that if the page gets * unmapped afterwards, the call to kvm_unmap_hva will take it away * from us again properly. This smp_rmb() interacts with the smp_wmb() * in kvm_mmu_notifier_invalidate_. */ smp_rmb(); pfn = gfn_to_pfn_prot(vcpu->kvm, gfn, write_fault, &writable); if (is_error_pfn(pfn)) return -EFAULT; new_pte = pfn_pte(pfn, PAGE_S2); coherent_icache_guest_page(vcpu->kvm, gfn); spin_lock(&vcpu->kvm->mmu_lock); if (mmu_notifier_retry(vcpu->kvm, mmu_seq)) goto out_unlock; if (writable) { pte_val(new_pte) |= L_PTE_S2_RDWR; kvm_set_pfn_dirty(pfn); } stage2_set_pte(vcpu->kvm, memcache, fault_ipa, &new_pte, false); out_unlock: spin_unlock(&vcpu->kvm->mmu_lock); kvm_release_pfn_clean(pfn); return 0; } /** * kvm_handle_guest_abort - handles all 2nd stage aborts * @vcpu: the VCPU pointer * @run: the kvm_run structure * * Any abort that gets to the host is almost guaranteed to be caused by a * missing second stage translation table entry, which can mean that either the * guest simply needs more memory and we must allocate an appropriate page or it * can mean that the guest tried to access I/O memory, which is emulated by user * space. The distinction is based on the IPA causing the fault and whether this * memory region has been registered as standard RAM by user space. */ int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run) { unsigned long fault_status; phys_addr_t fault_ipa; struct kvm_memory_slot *memslot; bool is_iabt; gfn_t gfn; int ret, idx; is_iabt = kvm_vcpu_trap_is_iabt(vcpu); fault_ipa = kvm_vcpu_get_fault_ipa(vcpu); trace_kvm_guest_fault(*vcpu_pc(vcpu), kvm_vcpu_get_hsr(vcpu), kvm_vcpu_get_hfar(vcpu), fault_ipa); /* Check the stage-2 fault is trans. fault or write fault */ fault_status = kvm_vcpu_trap_get_fault(vcpu); if (fault_status != FSC_FAULT && fault_status != FSC_PERM) { kvm_err("Unsupported fault status: EC=%#x DFCS=%#lx\n", kvm_vcpu_trap_get_class(vcpu), fault_status); return -EFAULT; } idx = srcu_read_lock(&vcpu->kvm->srcu); gfn = fault_ipa >> PAGE_SHIFT; if (!kvm_is_visible_gfn(vcpu->kvm, gfn)) { if (is_iabt) { /* Prefetch Abort on I/O address */ kvm_inject_pabt(vcpu, kvm_vcpu_get_hfar(vcpu)); ret = 1; goto out_unlock; } if (fault_status != FSC_FAULT) { kvm_err("Unsupported fault status on io memory: %#lx\n", fault_status); ret = -EFAULT; goto out_unlock; } /* Adjust page offset */ fault_ipa |= kvm_vcpu_get_hfar(vcpu) & ~PAGE_MASK; ret = io_mem_abort(vcpu, run, fault_ipa); goto out_unlock; } memslot = gfn_to_memslot(vcpu->kvm, gfn); ret = user_mem_abort(vcpu, fault_ipa, gfn, memslot, fault_status); if (ret == 0) ret = 1; out_unlock: srcu_read_unlock(&vcpu->kvm->srcu, idx); return ret; } static void handle_hva_to_gpa(struct kvm *kvm, unsigned long start, unsigned long end, void (*handler)(struct kvm *kvm, gpa_t gpa, void *data), void *data) { struct kvm_memslots *slots; struct kvm_memory_slot *memslot; slots = kvm_memslots(kvm); /* we only care about the pages that the guest sees */ kvm_for_each_memslot(memslot, slots) { unsigned long hva_start, hva_end; gfn_t gfn, gfn_end; hva_start = max(start, memslot->userspace_addr); hva_end = min(end, memslot->userspace_addr + (memslot->npages << PAGE_SHIFT)); if (hva_start >= hva_end) continue; /* * {gfn(page) | page intersects with [hva_start, hva_end)} = * {gfn_start, gfn_start+1, ..., gfn_end-1}. */ gfn = hva_to_gfn_memslot(hva_start, memslot); gfn_end = hva_to_gfn_memslot(hva_end + PAGE_SIZE - 1, memslot); for (; gfn < gfn_end; ++gfn) { gpa_t gpa = gfn << PAGE_SHIFT; handler(kvm, gpa, data); } } } static void kvm_unmap_hva_handler(struct kvm *kvm, gpa_t gpa, void *data) { unmap_stage2_range(kvm, gpa, PAGE_SIZE); kvm_tlb_flush_vmid(kvm); } int kvm_unmap_hva(struct kvm *kvm, unsigned long hva) { unsigned long end = hva + PAGE_SIZE; if (!kvm->arch.pgd) return 0; trace_kvm_unmap_hva(hva); handle_hva_to_gpa(kvm, hva, end, &kvm_unmap_hva_handler, NULL); return 0; } int kvm_unmap_hva_range(struct kvm *kvm, unsigned long start, unsigned long end) { if (!kvm->arch.pgd) return 0; trace_kvm_unmap_hva_range(start, end); handle_hva_to_gpa(kvm, start, end, &kvm_unmap_hva_handler, NULL); return 0; } static void kvm_set_spte_handler(struct kvm *kvm, gpa_t gpa, void *data) { pte_t *pte = (pte_t *)data; stage2_set_pte(kvm, NULL, gpa, pte, false); } void kvm_set_spte_hva(struct kvm *kvm, unsigned long hva, pte_t pte) { unsigned long end = hva + PAGE_SIZE; pte_t stage2_pte; if (!kvm->arch.pgd) return; trace_kvm_set_spte_hva(hva); stage2_pte = pfn_pte(pte_pfn(pte), PAGE_S2); handle_hva_to_gpa(kvm, hva, end, &kvm_set_spte_handler, &stage2_pte); } void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu) { mmu_free_memory_cache(&vcpu->arch.mmu_page_cache); } phys_addr_t kvm_mmu_get_httbr(void) { VM_BUG_ON(!virt_addr_valid(hyp_pgd)); return virt_to_phys(hyp_pgd); } int kvm_mmu_init(void) { if (!hyp_pgd) { kvm_err("Hyp mode PGD not allocated\n"); return -ENOMEM; } return 0; } /** * kvm_clear_idmap - remove all idmaps from the hyp pgd * * Free the underlying pmds for all pgds in range and clear the pgds (but * don't free them) afterwards. */ void kvm_clear_hyp_idmap(void) { unsigned long addr, end; unsigned long next; pgd_t *pgd = hyp_pgd; pud_t *pud; pmd_t *pmd; addr = virt_to_phys(__hyp_idmap_text_start); end = virt_to_phys(__hyp_idmap_text_end); pgd += pgd_index(addr); do { next = pgd_addr_end(addr, end); if (pgd_none_or_clear_bad(pgd)) continue; pud = pud_offset(pgd, addr); pmd = pmd_offset(pud, addr); pud_clear(pud); clean_pmd_entry(pmd); pmd_free(NULL, (pmd_t *)((unsigned long)pmd & PAGE_MASK)); } while (pgd++, addr = next, addr < end); }