/* * Copyright (C) 2012,2013 - ARM Ltd * Author: Marc Zyngier * * 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, see . */ #ifndef __ARM64_KVM_MMU_H__ #define __ARM64_KVM_MMU_H__ #include #include #include /* * As ARMv8.0 only has the TTBR0_EL2 register, we cannot express * "negative" addresses. This makes it impossible to directly share * mappings with the kernel. * * Instead, give the HYP mode its own VA region at a fixed offset from * the kernel by just masking the top bits (which are all ones for a * kernel address). We need to find out how many bits to mask. * * We want to build a set of page tables that cover both parts of the * idmap (the trampoline page used to initialize EL2), and our normal * runtime VA space, at the same time. * * Given that the kernel uses VA_BITS for its entire address space, * and that half of that space (VA_BITS - 1) is used for the linear * mapping, we can also limit the EL2 space to (VA_BITS - 1). * * The main question is "Within the VA_BITS space, does EL2 use the * top or the bottom half of that space to shadow the kernel's linear * mapping?". As we need to idmap the trampoline page, this is * determined by the range in which this page lives. * * If the page is in the bottom half, we have to use the top half. If * the page is in the top half, we have to use the bottom half: * * T = __pa_symbol(__hyp_idmap_text_start) * if (T & BIT(VA_BITS - 1)) * HYP_VA_MIN = 0 //idmap in upper half * else * HYP_VA_MIN = 1 << (VA_BITS - 1) * HYP_VA_MAX = HYP_VA_MIN + (1 << (VA_BITS - 1)) - 1 * * This of course assumes that the trampoline page exists within the * VA_BITS range. If it doesn't, then it means we're in the odd case * where the kernel idmap (as well as HYP) uses more levels than the * kernel runtime page tables (as seen when the kernel is configured * for 4k pages, 39bits VA, and yet memory lives just above that * limit, forcing the idmap to use 4 levels of page tables while the * kernel itself only uses 3). In this particular case, it doesn't * matter which side of VA_BITS we use, as we're guaranteed not to * conflict with anything. * * When using VHE, there are no separate hyp mappings and all KVM * functionality is already mapped as part of the main kernel * mappings, and none of this applies in that case. */ #ifdef __ASSEMBLY__ #include /* * Convert a kernel VA into a HYP VA. * reg: VA to be converted. * * The actual code generation takes place in kvm_update_va_mask, and * the instructions below are only there to reserve the space and * perform the register allocation (kvm_update_va_mask uses the * specific registers encoded in the instructions). */ .macro kern_hyp_va reg alternative_cb kvm_update_va_mask and \reg, \reg, #1 /* mask with va_mask */ ror \reg, \reg, #1 /* rotate to the first tag bit */ add \reg, \reg, #0 /* insert the low 12 bits of the tag */ add \reg, \reg, #0, lsl 12 /* insert the top 12 bits of the tag */ ror \reg, \reg, #63 /* rotate back */ alternative_cb_end .endm #else #include #include #include #include #include void kvm_update_va_mask(struct alt_instr *alt, __le32 *origptr, __le32 *updptr, int nr_inst); static inline unsigned long __kern_hyp_va(unsigned long v) { asm volatile(ALTERNATIVE_CB("and %0, %0, #1\n" "ror %0, %0, #1\n" "add %0, %0, #0\n" "add %0, %0, #0, lsl 12\n" "ror %0, %0, #63\n", kvm_update_va_mask) : "+r" (v)); return v; } #define kern_hyp_va(v) ((typeof(v))(__kern_hyp_va((unsigned long)(v)))) /* * Obtain the PC-relative address of a kernel symbol * s: symbol * * The goal of this macro is to return a symbol's address based on a * PC-relative computation, as opposed to a loading the VA from a * constant pool or something similar. This works well for HYP, as an * absolute VA is guaranteed to be wrong. Only use this if trying to * obtain the address of a symbol (i.e. not something you obtained by * following a pointer). */ #define hyp_symbol_addr(s) \ ({ \ typeof(s) *addr; \ asm("adrp %0, %1\n" \ "add %0, %0, :lo12:%1\n" \ : "=r" (addr) : "S" (&s)); \ addr; \ }) /* * We currently only support a 40bit IPA. */ #define KVM_PHYS_SHIFT (40) #define KVM_PHYS_SIZE (1UL << KVM_PHYS_SHIFT) #define KVM_PHYS_MASK (KVM_PHYS_SIZE - 1UL) #include int create_hyp_mappings(void *from, void *to, pgprot_t prot); int create_hyp_io_mappings(phys_addr_t phys_addr, size_t size, void __iomem **kaddr, void __iomem **haddr); int create_hyp_exec_mappings(phys_addr_t phys_addr, size_t size, void **haddr); void free_hyp_pgds(void); void stage2_unmap_vm(struct kvm *kvm); int kvm_alloc_stage2_pgd(struct kvm *kvm); void kvm_free_stage2_pgd(struct kvm *kvm); int kvm_phys_addr_ioremap(struct kvm *kvm, phys_addr_t guest_ipa, phys_addr_t pa, unsigned long size, bool writable); int kvm_handle_guest_abort(struct kvm_vcpu *vcpu, struct kvm_run *run); void kvm_mmu_free_memory_caches(struct kvm_vcpu *vcpu); phys_addr_t kvm_mmu_get_httbr(void); phys_addr_t kvm_get_idmap_vector(void); int kvm_mmu_init(void); void kvm_clear_hyp_idmap(void); #define kvm_mk_pmd(ptep) \ __pmd(__phys_to_pmd_val(__pa(ptep)) | PMD_TYPE_TABLE) #define kvm_mk_pud(pmdp) \ __pud(__phys_to_pud_val(__pa(pmdp)) | PMD_TYPE_TABLE) #define kvm_mk_pgd(pudp) \ __pgd(__phys_to_pgd_val(__pa(pudp)) | PUD_TYPE_TABLE) static inline pte_t kvm_s2pte_mkwrite(pte_t pte) { pte_val(pte) |= PTE_S2_RDWR; return pte; } static inline pmd_t kvm_s2pmd_mkwrite(pmd_t pmd) { pmd_val(pmd) |= PMD_S2_RDWR; return pmd; } static inline pte_t kvm_s2pte_mkexec(pte_t pte) { pte_val(pte) &= ~PTE_S2_XN; return pte; } static inline pmd_t kvm_s2pmd_mkexec(pmd_t pmd) { pmd_val(pmd) &= ~PMD_S2_XN; return pmd; } static inline void kvm_set_s2pte_readonly(pte_t *ptep) { pteval_t old_pteval, pteval; pteval = READ_ONCE(pte_val(*ptep)); do { old_pteval = pteval; pteval &= ~PTE_S2_RDWR; pteval |= PTE_S2_RDONLY; pteval = cmpxchg_relaxed(&pte_val(*ptep), old_pteval, pteval); } while (pteval != old_pteval); } static inline bool kvm_s2pte_readonly(pte_t *ptep) { return (READ_ONCE(pte_val(*ptep)) & PTE_S2_RDWR) == PTE_S2_RDONLY; } static inline bool kvm_s2pte_exec(pte_t *ptep) { return !(READ_ONCE(pte_val(*ptep)) & PTE_S2_XN); } static inline void kvm_set_s2pmd_readonly(pmd_t *pmdp) { kvm_set_s2pte_readonly((pte_t *)pmdp); } static inline bool kvm_s2pmd_readonly(pmd_t *pmdp) { return kvm_s2pte_readonly((pte_t *)pmdp); } static inline bool kvm_s2pmd_exec(pmd_t *pmdp) { return !(READ_ONCE(pmd_val(*pmdp)) & PMD_S2_XN); } static inline bool kvm_page_empty(void *ptr) { struct page *ptr_page = virt_to_page(ptr); return page_count(ptr_page) == 1; } #define hyp_pte_table_empty(ptep) kvm_page_empty(ptep) #ifdef __PAGETABLE_PMD_FOLDED #define hyp_pmd_table_empty(pmdp) (0) #else #define hyp_pmd_table_empty(pmdp) kvm_page_empty(pmdp) #endif #ifdef __PAGETABLE_PUD_FOLDED #define hyp_pud_table_empty(pudp) (0) #else #define hyp_pud_table_empty(pudp) kvm_page_empty(pudp) #endif struct kvm; #define kvm_flush_dcache_to_poc(a,l) __flush_dcache_area((a), (l)) static inline bool vcpu_has_cache_enabled(struct kvm_vcpu *vcpu) { return (vcpu_read_sys_reg(vcpu, SCTLR_EL1) & 0b101) == 0b101; } static inline void __clean_dcache_guest_page(kvm_pfn_t pfn, unsigned long size) { void *va = page_address(pfn_to_page(pfn)); /* * With FWB, we ensure that the guest always accesses memory using * cacheable attributes, and we don't have to clean to PoC when * faulting in pages. Furthermore, FWB implies IDC, so cleaning to * PoU is not required either in this case. */ if (cpus_have_const_cap(ARM64_HAS_STAGE2_FWB)) return; kvm_flush_dcache_to_poc(va, size); } static inline void __invalidate_icache_guest_page(kvm_pfn_t pfn, unsigned long size) { if (icache_is_aliasing()) { /* any kind of VIPT cache */ __flush_icache_all(); } else if (is_kernel_in_hyp_mode() || !icache_is_vpipt()) { /* PIPT or VPIPT at EL2 (see comment in __kvm_tlb_flush_vmid_ipa) */ void *va = page_address(pfn_to_page(pfn)); invalidate_icache_range((unsigned long)va, (unsigned long)va + size); } } static inline void __kvm_flush_dcache_pte(pte_t pte) { if (!cpus_have_const_cap(ARM64_HAS_STAGE2_FWB)) { struct page *page = pte_page(pte); kvm_flush_dcache_to_poc(page_address(page), PAGE_SIZE); } } static inline void __kvm_flush_dcache_pmd(pmd_t pmd) { if (!cpus_have_const_cap(ARM64_HAS_STAGE2_FWB)) { struct page *page = pmd_page(pmd); kvm_flush_dcache_to_poc(page_address(page), PMD_SIZE); } } static inline void __kvm_flush_dcache_pud(pud_t pud) { if (!cpus_have_const_cap(ARM64_HAS_STAGE2_FWB)) { struct page *page = pud_page(pud); kvm_flush_dcache_to_poc(page_address(page), PUD_SIZE); } } #define kvm_virt_to_phys(x) __pa_symbol(x) void kvm_set_way_flush(struct kvm_vcpu *vcpu); void kvm_toggle_cache(struct kvm_vcpu *vcpu, bool was_enabled); static inline bool __kvm_cpu_uses_extended_idmap(void) { return __cpu_uses_extended_idmap_level(); } static inline unsigned long __kvm_idmap_ptrs_per_pgd(void) { return idmap_ptrs_per_pgd; } /* * Can't use pgd_populate here, because the extended idmap adds an extra level * above CONFIG_PGTABLE_LEVELS (which is 2 or 3 if we're using the extended * idmap), and pgd_populate is only available if CONFIG_PGTABLE_LEVELS = 4. */ static inline void __kvm_extend_hypmap(pgd_t *boot_hyp_pgd, pgd_t *hyp_pgd, pgd_t *merged_hyp_pgd, unsigned long hyp_idmap_start) { int idmap_idx; u64 pgd_addr; /* * Use the first entry to access the HYP mappings. It is * guaranteed to be free, otherwise we wouldn't use an * extended idmap. */ VM_BUG_ON(pgd_val(merged_hyp_pgd[0])); pgd_addr = __phys_to_pgd_val(__pa(hyp_pgd)); merged_hyp_pgd[0] = __pgd(pgd_addr | PMD_TYPE_TABLE); /* * Create another extended level entry that points to the boot HYP map, * which contains an ID mapping of the HYP init code. We essentially * merge the boot and runtime HYP maps by doing so, but they don't * overlap anyway, so this is fine. */ idmap_idx = hyp_idmap_start >> VA_BITS; VM_BUG_ON(pgd_val(merged_hyp_pgd[idmap_idx])); pgd_addr = __phys_to_pgd_val(__pa(boot_hyp_pgd)); merged_hyp_pgd[idmap_idx] = __pgd(pgd_addr | PMD_TYPE_TABLE); } static inline unsigned int kvm_get_vmid_bits(void) { int reg = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1); return (cpuid_feature_extract_unsigned_field(reg, ID_AA64MMFR1_VMIDBITS_SHIFT) == 2) ? 16 : 8; } /* * We are not in the kvm->srcu critical section most of the time, so we take * the SRCU read lock here. Since we copy the data from the user page, we * can immediately drop the lock again. */ static inline int kvm_read_guest_lock(struct kvm *kvm, gpa_t gpa, void *data, unsigned long len) { int srcu_idx = srcu_read_lock(&kvm->srcu); int ret = kvm_read_guest(kvm, gpa, data, len); srcu_read_unlock(&kvm->srcu, srcu_idx); return ret; } static inline int kvm_write_guest_lock(struct kvm *kvm, gpa_t gpa, const void *data, unsigned long len) { int srcu_idx = srcu_read_lock(&kvm->srcu); int ret = kvm_write_guest(kvm, gpa, data, len); srcu_read_unlock(&kvm->srcu, srcu_idx); return ret; } #ifdef CONFIG_KVM_INDIRECT_VECTORS /* * EL2 vectors can be mapped and rerouted in a number of ways, * depending on the kernel configuration and CPU present: * * - If the CPU has the ARM64_HARDEN_BRANCH_PREDICTOR cap, the * hardening sequence is placed in one of the vector slots, which is * executed before jumping to the real vectors. * * - If the CPU has both the ARM64_HARDEN_EL2_VECTORS cap and the * ARM64_HARDEN_BRANCH_PREDICTOR cap, the slot containing the * hardening sequence is mapped next to the idmap page, and executed * before jumping to the real vectors. * * - If the CPU only has the ARM64_HARDEN_EL2_VECTORS cap, then an * empty slot is selected, mapped next to the idmap page, and * executed before jumping to the real vectors. * * Note that ARM64_HARDEN_EL2_VECTORS is somewhat incompatible with * VHE, as we don't have hypervisor-specific mappings. If the system * is VHE and yet selects this capability, it will be ignored. */ #include extern void *__kvm_bp_vect_base; extern int __kvm_harden_el2_vector_slot; static inline void *kvm_get_hyp_vector(void) { struct bp_hardening_data *data = arm64_get_bp_hardening_data(); void *vect = kern_hyp_va(kvm_ksym_ref(__kvm_hyp_vector)); int slot = -1; if ((cpus_have_const_cap(ARM64_HARDEN_BRANCH_PREDICTOR) || cpus_have_const_cap(ARM64_SPECTRE_BHB)) && data->template_start) { vect = kern_hyp_va(kvm_ksym_ref(__bp_harden_hyp_vecs_start)); slot = data->hyp_vectors_slot; } if (this_cpu_has_cap(ARM64_HARDEN_EL2_VECTORS) && !has_vhe()) { vect = __kvm_bp_vect_base; if (slot == -1) slot = __kvm_harden_el2_vector_slot; } if (slot != -1) vect += slot * SZ_2K; return vect; } /* This is only called on a !VHE system */ static inline int kvm_map_vectors(void) { /* * HBP = ARM64_HARDEN_BRANCH_PREDICTOR * HEL2 = ARM64_HARDEN_EL2_VECTORS * * !HBP + !HEL2 -> use direct vectors * HBP + !HEL2 -> use hardened vectors in place * !HBP + HEL2 -> allocate one vector slot and use exec mapping * HBP + HEL2 -> use hardened vertors and use exec mapping */ if (cpus_have_const_cap(ARM64_HARDEN_BRANCH_PREDICTOR) || cpus_have_const_cap(ARM64_SPECTRE_BHB)) { __kvm_bp_vect_base = kvm_ksym_ref(__bp_harden_hyp_vecs_start); __kvm_bp_vect_base = kern_hyp_va(__kvm_bp_vect_base); } if (cpus_have_const_cap(ARM64_HARDEN_EL2_VECTORS)) { phys_addr_t vect_pa = __pa_symbol(__bp_harden_hyp_vecs_start); unsigned long size = (__bp_harden_hyp_vecs_end - __bp_harden_hyp_vecs_start); /* * Always allocate a spare vector slot, as we don't * know yet which CPUs have a BP hardening slot that * we can reuse. */ __kvm_harden_el2_vector_slot = atomic_inc_return(&arm64_el2_vector_last_slot); BUG_ON(__kvm_harden_el2_vector_slot >= BP_HARDEN_EL2_SLOTS); return create_hyp_exec_mappings(vect_pa, size, &__kvm_bp_vect_base); } return 0; } #else static inline void *kvm_get_hyp_vector(void) { return kern_hyp_va(kvm_ksym_ref(__kvm_hyp_vector)); } static inline int kvm_map_vectors(void) { return 0; } #endif #ifdef CONFIG_ARM64_SSBD DECLARE_PER_CPU_READ_MOSTLY(u64, arm64_ssbd_callback_required); static inline int hyp_map_aux_data(void) { int cpu, err; for_each_possible_cpu(cpu) { u64 *ptr; ptr = per_cpu_ptr(&arm64_ssbd_callback_required, cpu); err = create_hyp_mappings(ptr, ptr + 1, PAGE_HYP); if (err) return err; } return 0; } #else static inline int hyp_map_aux_data(void) { return 0; } #endif #define kvm_phys_to_vttbr(addr) phys_to_ttbr(addr) #endif /* __ASSEMBLY__ */ #endif /* __ARM64_KVM_MMU_H__ */