diff options
Diffstat (limited to 'arch/arm/kvm/mmu.c')
| -rw-r--r-- | arch/arm/kvm/mmu.c | 1102 |
1 files changed, 1102 insertions, 0 deletions
diff --git a/arch/arm/kvm/mmu.c b/arch/arm/kvm/mmu.c new file mode 100644 index 00000000000..16f804938b8 --- /dev/null +++ b/arch/arm/kvm/mmu.c @@ -0,0 +1,1102 @@ +/* + * Copyright (C) 2012 - Virtual Open Systems and Columbia University + * Author: Christoffer Dall <c.dall@virtualopensystems.com> + * + * 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 <linux/mman.h> +#include <linux/kvm_host.h> +#include <linux/io.h> +#include <linux/hugetlb.h> +#include <trace/events/kvm.h> +#include <asm/pgalloc.h> +#include <asm/cacheflush.h> +#include <asm/kvm_arm.h> +#include <asm/kvm_mmu.h> +#include <asm/kvm_mmio.h> +#include <asm/kvm_asm.h> +#include <asm/kvm_emulate.h> + +#include "trace.h" + +extern char __hyp_idmap_text_start[], __hyp_idmap_text_end[]; + +static pgd_t *boot_hyp_pgd; +static pgd_t *hyp_pgd; +static DEFINE_MUTEX(kvm_hyp_pgd_mutex); + +static void *init_bounce_page; +static unsigned long hyp_idmap_start; +static unsigned long hyp_idmap_end; +static phys_addr_t hyp_idmap_vector; + +#define pgd_order get_order(PTRS_PER_PGD * sizeof(pgd_t)) + +#define kvm_pmd_huge(_x) (pmd_huge(_x) || pmd_trans_huge(_x)) + +static void kvm_tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa) +{ + /* + * This function also gets called when dealing with HYP page + * tables. As HYP doesn't have an associated struct kvm (and + * the HYP page tables are fairly static), we don't do + * anything there. + */ + if (kvm) + kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, kvm, ipa); +} + +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 bool page_empty(void *ptr) +{ + struct page *ptr_page = virt_to_page(ptr); + return page_count(ptr_page) == 1; +} + +static void clear_pud_entry(struct kvm *kvm, pud_t *pud, phys_addr_t addr) +{ + if (pud_huge(*pud)) { + pud_clear(pud); + kvm_tlb_flush_vmid_ipa(kvm, addr); + } else { + pmd_t *pmd_table = pmd_offset(pud, 0); + pud_clear(pud); + kvm_tlb_flush_vmid_ipa(kvm, addr); + pmd_free(NULL, pmd_table); + } + put_page(virt_to_page(pud)); +} + +static void clear_pmd_entry(struct kvm *kvm, pmd_t *pmd, phys_addr_t addr) +{ + if (kvm_pmd_huge(*pmd)) { + pmd_clear(pmd); + kvm_tlb_flush_vmid_ipa(kvm, addr); + } else { + pte_t *pte_table = pte_offset_kernel(pmd, 0); + pmd_clear(pmd); + kvm_tlb_flush_vmid_ipa(kvm, addr); + pte_free_kernel(NULL, pte_table); + } + put_page(virt_to_page(pmd)); +} + +static void clear_pte_entry(struct kvm *kvm, pte_t *pte, phys_addr_t addr) +{ + if (pte_present(*pte)) { + kvm_set_pte(pte, __pte(0)); + put_page(virt_to_page(pte)); + kvm_tlb_flush_vmid_ipa(kvm, addr); + } +} + +static void unmap_range(struct kvm *kvm, pgd_t *pgdp, + unsigned long long start, u64 size) +{ + pgd_t *pgd; + pud_t *pud; + pmd_t *pmd; + pte_t *pte; + unsigned long long addr = start, end = start + size; + u64 next; + + while (addr < end) { + pgd = pgdp + pgd_index(addr); + pud = pud_offset(pgd, addr); + pte = NULL; + if (pud_none(*pud)) { + addr = kvm_pud_addr_end(addr, end); + continue; + } + + if (pud_huge(*pud)) { + /* + * If we are dealing with a huge pud, just clear it and + * move on. + */ + clear_pud_entry(kvm, pud, addr); + addr = kvm_pud_addr_end(addr, end); + continue; + } + + pmd = pmd_offset(pud, addr); + if (pmd_none(*pmd)) { + addr = kvm_pmd_addr_end(addr, end); + continue; + } + + if (!kvm_pmd_huge(*pmd)) { + pte = pte_offset_kernel(pmd, addr); + clear_pte_entry(kvm, pte, addr); + next = addr + PAGE_SIZE; + } + + /* + * If the pmd entry is to be cleared, walk back up the ladder + */ + if (kvm_pmd_huge(*pmd) || (pte && page_empty(pte))) { + clear_pmd_entry(kvm, pmd, addr); + next = kvm_pmd_addr_end(addr, end); + if (page_empty(pmd) && !page_empty(pud)) { + clear_pud_entry(kvm, pud, addr); + next = kvm_pud_addr_end(addr, end); + } + } + + addr = next; + } +} + +static void stage2_flush_ptes(struct kvm *kvm, pmd_t *pmd, + phys_addr_t addr, phys_addr_t end) +{ + pte_t *pte; + + pte = pte_offset_kernel(pmd, addr); + do { + if (!pte_none(*pte)) { + hva_t hva = gfn_to_hva(kvm, addr >> PAGE_SHIFT); + kvm_flush_dcache_to_poc((void*)hva, PAGE_SIZE); + } + } while (pte++, addr += PAGE_SIZE, addr != end); +} + +static void stage2_flush_pmds(struct kvm *kvm, pud_t *pud, + phys_addr_t addr, phys_addr_t end) +{ + pmd_t *pmd; + phys_addr_t next; + + pmd = pmd_offset(pud, addr); + do { + next = kvm_pmd_addr_end(addr, end); + if (!pmd_none(*pmd)) { + if (kvm_pmd_huge(*pmd)) { + hva_t hva = gfn_to_hva(kvm, addr >> PAGE_SHIFT); + kvm_flush_dcache_to_poc((void*)hva, PMD_SIZE); + } else { + stage2_flush_ptes(kvm, pmd, addr, next); + } + } + } while (pmd++, addr = next, addr != end); +} + +static void stage2_flush_puds(struct kvm *kvm, pgd_t *pgd, + phys_addr_t addr, phys_addr_t end) +{ + pud_t *pud; + phys_addr_t next; + + pud = pud_offset(pgd, addr); + do { + next = kvm_pud_addr_end(addr, end); + if (!pud_none(*pud)) { + if (pud_huge(*pud)) { + hva_t hva = gfn_to_hva(kvm, addr >> PAGE_SHIFT); + kvm_flush_dcache_to_poc((void*)hva, PUD_SIZE); + } else { + stage2_flush_pmds(kvm, pud, addr, next); + } + } + } while (pud++, addr = next, addr != end); +} + +static void stage2_flush_memslot(struct kvm *kvm, + struct kvm_memory_slot *memslot) +{ + phys_addr_t addr = memslot->base_gfn << PAGE_SHIFT; + phys_addr_t end = addr + PAGE_SIZE * memslot->npages; + phys_addr_t next; + pgd_t *pgd; + + pgd = kvm->arch.pgd + pgd_index(addr); + do { + next = kvm_pgd_addr_end(addr, end); + stage2_flush_puds(kvm, pgd, addr, next); + } while (pgd++, addr = next, addr != end); +} + +/** + * stage2_flush_vm - Invalidate cache for pages mapped in stage 2 + * @kvm: The struct kvm pointer + * + * Go through the stage 2 page tables and invalidate any cache lines + * backing memory already mapped to the VM. + */ +void stage2_flush_vm(struct kvm *kvm) +{ + struct kvm_memslots *slots; + struct kvm_memory_slot *memslot; + int idx; + + idx = srcu_read_lock(&kvm->srcu); + spin_lock(&kvm->mmu_lock); + + slots = kvm_memslots(kvm); + kvm_for_each_memslot(memslot, slots) + stage2_flush_memslot(kvm, memslot); + + spin_unlock(&kvm->mmu_lock); + srcu_read_unlock(&kvm->srcu, idx); +} + +/** + * free_boot_hyp_pgd - free HYP boot page tables + * + * Free the HYP boot page tables. The bounce page is also freed. + */ +void free_boot_hyp_pgd(void) +{ + mutex_lock(&kvm_hyp_pgd_mutex); + + if (boot_hyp_pgd) { + unmap_range(NULL, boot_hyp_pgd, hyp_idmap_start, PAGE_SIZE); + unmap_range(NULL, boot_hyp_pgd, TRAMPOLINE_VA, PAGE_SIZE); + free_pages((unsigned long)boot_hyp_pgd, pgd_order); + boot_hyp_pgd = NULL; + } + + if (hyp_pgd) + unmap_range(NULL, hyp_pgd, TRAMPOLINE_VA, PAGE_SIZE); + + free_page((unsigned long)init_bounce_page); + init_bounce_page = NULL; + + mutex_unlock(&kvm_hyp_pgd_mutex); +} + +/** + * free_hyp_pgds - free Hyp-mode page tables + * + * Assumes hyp_pgd is a page table used strictly in Hyp-mode and + * therefore contains either mappings in the kernel memory area (above + * PAGE_OFFSET), or device mappings in the vmalloc range (from + * VMALLOC_START to VMALLOC_END). + * + * boot_hyp_pgd should only map two pages for the init code. + */ +void free_hyp_pgds(void) +{ + unsigned long addr; + + free_boot_hyp_pgd(); + + mutex_lock(&kvm_hyp_pgd_mutex); + + if (hyp_pgd) { + for (addr = PAGE_OFFSET; virt_addr_valid(addr); addr += PGDIR_SIZE) + unmap_range(NULL, hyp_pgd, KERN_TO_HYP(addr), PGDIR_SIZE); + for (addr = VMALLOC_START; is_vmalloc_addr((void*)addr); addr += PGDIR_SIZE) + unmap_range(NULL, hyp_pgd, KERN_TO_HYP(addr), PGDIR_SIZE); + + free_pages((unsigned long)hyp_pgd, pgd_order); + hyp_pgd = NULL; + } + + mutex_unlock(&kvm_hyp_pgd_mutex); +} + +static void create_hyp_pte_mappings(pmd_t *pmd, unsigned long start, + unsigned long end, unsigned long pfn, + pgprot_t prot) +{ + pte_t *pte; + unsigned long addr; + + addr = start; + do { + pte = pte_offset_kernel(pmd, addr); + kvm_set_pte(pte, pfn_pte(pfn, prot)); + get_page(virt_to_page(pte)); + kvm_flush_dcache_to_poc(pte, sizeof(*pte)); + pfn++; + } while (addr += PAGE_SIZE, addr != end); +} + +static int create_hyp_pmd_mappings(pud_t *pud, unsigned long start, + unsigned long end, unsigned long pfn, + pgprot_t prot) +{ + pmd_t *pmd; + pte_t *pte; + unsigned long addr, next; + + addr = start; + do { + 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); + get_page(virt_to_page(pmd)); + kvm_flush_dcache_to_poc(pmd, sizeof(*pmd)); + } + + next = pmd_addr_end(addr, end); + + create_hyp_pte_mappings(pmd, addr, next, pfn, prot); + pfn += (next - addr) >> PAGE_SHIFT; + } while (addr = next, addr != end); + + return 0; +} + +static int __create_hyp_mappings(pgd_t *pgdp, + unsigned long start, unsigned long end, + unsigned long pfn, pgprot_t prot) +{ + pgd_t *pgd; + pud_t *pud; + pmd_t *pmd; + unsigned long addr, next; + int err = 0; + + mutex_lock(&kvm_hyp_pgd_mutex); + addr = start & PAGE_MASK; + end = PAGE_ALIGN(end); + do { + pgd = pgdp + 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); + get_page(virt_to_page(pud)); + kvm_flush_dcache_to_poc(pud, sizeof(*pud)); + } + + next = pgd_addr_end(addr, end); + err = create_hyp_pmd_mappings(pud, addr, next, pfn, prot); + if (err) + goto out; + pfn += (next - addr) >> PAGE_SHIFT; + } while (addr = next, addr != end); +out: + mutex_unlock(&kvm_hyp_pgd_mutex); + return err; +} + +static phys_addr_t kvm_kaddr_to_phys(void *kaddr) +{ + if (!is_vmalloc_addr(kaddr)) { + BUG_ON(!virt_addr_valid(kaddr)); + return __pa(kaddr); + } else { + return page_to_phys(vmalloc_to_page(kaddr)) + + offset_in_page(kaddr); + } +} + +/** + * create_hyp_mappings - duplicate 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 (modulo HYP_PAGE_OFFSET) to the same underlying + * physical pages. + */ +int create_hyp_mappings(void *from, void *to) +{ + phys_addr_t phys_addr; + unsigned long virt_addr; + unsigned long start = KERN_TO_HYP((unsigned long)from); + unsigned long end = KERN_TO_HYP((unsigned long)to); + + start = start & PAGE_MASK; + end = PAGE_ALIGN(end); + + for (virt_addr = start; virt_addr < end; virt_addr += PAGE_SIZE) { + int err; + + phys_addr = kvm_kaddr_to_phys(from + virt_addr - start); + err = __create_hyp_mappings(hyp_pgd, virt_addr, + virt_addr + PAGE_SIZE, + __phys_to_pfn(phys_addr), + PAGE_HYP); + if (err) + return err; + } + + return 0; +} + +/** + * create_hyp_io_mappings - duplicate a kernel IO mapping into Hyp mode + * @from: The kernel start VA of the range + * @to: The kernel end VA of the range (exclusive) + * @phys_addr: The physical start address which gets mapped + * + * The resulting HYP VA is the same as the kernel VA, modulo + * HYP_PAGE_OFFSET. + */ +int create_hyp_io_mappings(void *from, void *to, phys_addr_t phys_addr) +{ + unsigned long start = KERN_TO_HYP((unsigned long)from); + unsigned long end = KERN_TO_HYP((unsigned long)to); + + /* Check for a valid kernel IO mapping */ + if (!is_vmalloc_addr(from) || !is_vmalloc_addr(to - 1)) + return -EINVAL; + + return __create_hyp_mappings(hyp_pgd, start, end, + __phys_to_pfn(phys_addr), PAGE_HYP_DEVICE); +} + +/** + * 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; + + memset(pgd, 0, PTRS_PER_S2_PGD * sizeof(pgd_t)); + kvm_clean_pgd(pgd); + kvm->arch.pgd = pgd; + + return 0; +} + +/** + * 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) +{ + unmap_range(kvm, kvm->arch.pgd, start, size); +} + +/** + * 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 pmd_t *stage2_get_pmd(struct kvm *kvm, struct kvm_mmu_memory_cache *cache, + phys_addr_t addr) +{ + pgd_t *pgd; + pud_t *pud; + pmd_t *pmd; + + pgd = kvm->arch.pgd + pgd_index(addr); + pud = pud_offset(pgd, addr); + if (pud_none(*pud)) { + if (!cache) + return NULL; + pmd = mmu_memory_cache_alloc(cache); + pud_populate(NULL, pud, pmd); + get_page(virt_to_page(pud)); + } + + return pmd_offset(pud, addr); +} + +static int stage2_set_pmd_huge(struct kvm *kvm, struct kvm_mmu_memory_cache + *cache, phys_addr_t addr, const pmd_t *new_pmd) +{ + pmd_t *pmd, old_pmd; + + pmd = stage2_get_pmd(kvm, cache, addr); + VM_BUG_ON(!pmd); + + /* + * Mapping in huge pages should only happen through a fault. If a + * page is merged into a transparent huge page, the individual + * subpages of that huge page should be unmapped through MMU + * notifiers before we get here. + * + * Merging of CompoundPages is not supported; they should become + * splitting first, unmapped, merged, and mapped back in on-demand. + */ + VM_BUG_ON(pmd_present(*pmd) && pmd_pfn(*pmd) != pmd_pfn(*new_pmd)); + + old_pmd = *pmd; + kvm_set_pmd(pmd, *new_pmd); + if (pmd_present(old_pmd)) + kvm_tlb_flush_vmid_ipa(kvm, addr); + else + get_page(virt_to_page(pmd)); + return 0; +} + +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) +{ + pmd_t *pmd; + pte_t *pte, old_pte; + + /* Create stage-2 page table mapping - Level 1 */ + pmd = stage2_get_pmd(kvm, cache, addr); + if (!pmd) { + /* + * Ignore calls from kvm_set_spte_hva for unallocated + * address ranges. + */ + return 0; + } + + /* Create stage-2 page mappings - Level 2 */ + if (pmd_none(*pmd)) { + if (!cache) + return 0; /* ignore calls from kvm_set_spte_hva */ + pte = mmu_memory_cache_alloc(cache); + kvm_clean_pte(pte); + pmd_populate_kernel(NULL, pmd, pte); + get_page(virt_to_page(pmd)); + } + + 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_ipa(kvm, addr); + 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); + + 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 bool transparent_hugepage_adjust(pfn_t *pfnp, phys_addr_t *ipap) +{ + pfn_t pfn = *pfnp; + gfn_t gfn = *ipap >> PAGE_SHIFT; + + if (PageTransCompound(pfn_to_page(pfn))) { + unsigned long mask; + /* + * The address we faulted on is backed by a transparent huge + * page. However, because we map the compound huge page and + * not the individual tail page, we need to transfer the + * refcount to the head page. We have to be careful that the + * THP doesn't start to split while we are adjusting the + * refcounts. + * + * We are sure this doesn't happen, because mmu_notifier_retry + * was successful and we are holding the mmu_lock, so if this + * THP is trying to split, it will be blocked in the mmu + * notifier before touching any of the pages, specifically + * before being able to call __split_huge_page_refcount(). + * + * We can therefore safely transfer the refcount from PG_tail + * to PG_head and switch the pfn from a tail page to the head + * page accordingly. + */ + mask = PTRS_PER_PMD - 1; + VM_BUG_ON((gfn & mask) != (pfn & mask)); + if (pfn & mask) { + *ipap &= PMD_MASK; + kvm_release_pfn_clean(pfn); + pfn &= ~mask; + kvm_get_pfn(pfn); + *pfnp = pfn; + } + + return true; + } + + return false; +} + +static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, + struct kvm_memory_slot *memslot, + unsigned long fault_status) +{ + int ret; + bool write_fault, writable, hugetlb = false, force_pte = false; + unsigned long mmu_seq; + gfn_t gfn = fault_ipa >> PAGE_SHIFT; + unsigned long hva = gfn_to_hva(vcpu->kvm, gfn); + struct kvm *kvm = vcpu->kvm; + struct kvm_mmu_memory_cache *memcache = &vcpu->arch.mmu_page_cache; + struct vm_area_struct *vma; + pfn_t pfn; + + 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; + } + + /* Let's check if we will get back a huge page backed by hugetlbfs */ + down_read(¤t->mm->mmap_sem); + vma = find_vma_intersection(current->mm, hva, hva + 1); + if (is_vm_hugetlb_page(vma)) { + hugetlb = true; + gfn = (fault_ipa & PMD_MASK) >> PAGE_SHIFT; + } else { + /* + * Pages belonging to memslots that don't have the same + * alignment for userspace and IPA cannot be mapped using + * block descriptors even if the pages belong to a THP for + * the process, because the stage-2 block descriptor will + * cover more than a single THP and we loose atomicity for + * unmapping, updates, and splits of the THP or other pages + * in the stage-2 block range. + */ + if ((memslot->userspace_addr & ~PMD_MASK) != + ((memslot->base_gfn << PAGE_SHIFT) & ~PMD_MASK)) + force_pte = true; + } + up_read(¤t->mm->mmap_sem); + + /* 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_<page|range_end>. + */ + smp_rmb(); + + pfn = gfn_to_pfn_prot(kvm, gfn, write_fault, &writable); + if (is_error_pfn(pfn)) + return -EFAULT; + + spin_lock(&kvm->mmu_lock); + if (mmu_notifier_retry(kvm, mmu_seq)) + goto out_unlock; + if (!hugetlb && !force_pte) + hugetlb = transparent_hugepage_adjust(&pfn, &fault_ipa); + + if (hugetlb) { + pmd_t new_pmd = pfn_pmd(pfn, PAGE_S2); + new_pmd = pmd_mkhuge(new_pmd); + if (writable) { + kvm_set_s2pmd_writable(&new_pmd); + kvm_set_pfn_dirty(pfn); + } + coherent_cache_guest_page(vcpu, hva & PMD_MASK, PMD_SIZE); + ret = stage2_set_pmd_huge(kvm, memcache, fault_ipa, &new_pmd); + } else { + pte_t new_pte = pfn_pte(pfn, PAGE_S2); + if (writable) { + kvm_set_s2pte_writable(&new_pte); + kvm_set_pfn_dirty(pfn); + } + coherent_cache_guest_page(vcpu, hva, PAGE_SIZE); + ret = stage2_set_pte(kvm, memcache, fault_ipa, &new_pte, false); + } + + +out_unlock: + spin_unlock(&kvm->mmu_lock); + kvm_release_pfn_clean(pfn); + return ret; +} + +/** + * 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; + } + + /* + * The IPA is reported as [MAX:12], so we need to + * complement it with the bottom 12 bits from the + * faulting VA. This is always 12 bits, irrespective + * of the page size. + */ + fault_ipa |= kvm_vcpu_get_hfar(vcpu) & ((1 << 12) - 1); + 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, 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); +} + +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) +{ + return virt_to_phys(hyp_pgd); +} + +phys_addr_t kvm_mmu_get_boot_httbr(void) +{ + return virt_to_phys(boot_hyp_pgd); +} + +phys_addr_t kvm_get_idmap_vector(void) +{ + return hyp_idmap_vector; +} + +int kvm_mmu_init(void) +{ + int err; + + hyp_idmap_start = kvm_virt_to_phys(__hyp_idmap_text_start); + hyp_idmap_end = kvm_virt_to_phys(__hyp_idmap_text_end); + hyp_idmap_vector = kvm_virt_to_phys(__kvm_hyp_init); + + if ((hyp_idmap_start ^ hyp_idmap_end) & PAGE_MASK) { + /* + * Our init code is crossing a page boundary. Allocate + * a bounce page, copy the code over and use that. + */ + size_t len = __hyp_idmap_text_end - __hyp_idmap_text_start; + phys_addr_t phys_base; + + init_bounce_page = (void *)__get_free_page(GFP_KERNEL); + if (!init_bounce_page) { + kvm_err("Couldn't allocate HYP init bounce page\n"); + err = -ENOMEM; + goto out; + } + + memcpy(init_bounce_page, __hyp_idmap_text_start, len); + /* + * Warning: the code we just copied to the bounce page + * must be flushed to the point of coherency. + * Otherwise, the data may be sitting in L2, and HYP + * mode won't be able to observe it as it runs with + * caches off at that point. + */ + kvm_flush_dcache_to_poc(init_bounce_page, len); + + phys_base = kvm_virt_to_phys(init_bounce_page); + hyp_idmap_vector += phys_base - hyp_idmap_start; + hyp_idmap_start = phys_base; + hyp_idmap_end = phys_base + len; + + kvm_info("Using HYP init bounce page @%lx\n", + (unsigned long)phys_base); + } + + hyp_pgd = (pgd_t *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, pgd_order); + boot_hyp_pgd = (pgd_t *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, pgd_order); + + if (!hyp_pgd || !boot_hyp_pgd) { + kvm_err("Hyp mode PGD not allocated\n"); + err = -ENOMEM; + goto out; + } + + /* Create the idmap in the boot page tables */ + err = __create_hyp_mappings(boot_hyp_pgd, + hyp_idmap_start, hyp_idmap_end, + __phys_to_pfn(hyp_idmap_start), + PAGE_HYP); + + if (err) { + kvm_err("Failed to idmap %lx-%lx\n", + hyp_idmap_start, hyp_idmap_end); + goto out; + } + + /* Map the very same page at the trampoline VA */ + err = __create_hyp_mappings(boot_hyp_pgd, + TRAMPOLINE_VA, TRAMPOLINE_VA + PAGE_SIZE, + __phys_to_pfn(hyp_idmap_start), + PAGE_HYP); + if (err) { + kvm_err("Failed to map trampoline @%lx into boot HYP pgd\n", + TRAMPOLINE_VA); + goto out; + } + + /* Map the same page again into the runtime page tables */ + err = __create_hyp_mappings(hyp_pgd, + TRAMPOLINE_VA, TRAMPOLINE_VA + PAGE_SIZE, + __phys_to_pfn(hyp_idmap_start), + PAGE_HYP); + if (err) { + kvm_err("Failed to map trampoline @%lx into runtime HYP pgd\n", + TRAMPOLINE_VA); + goto out; + } + + return 0; +out: + free_hyp_pgds(); + return err; +} |