/* * 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. */ #define HYP_PAGE_OFFSET_HIGH_MASK ((UL(1) << VA_BITS) - 1) #define HYP_PAGE_OFFSET_LOW_MASK ((UL(1) << (VA_BITS - 1)) - 1) #ifdef __ASSEMBLY__ #include #include /* * Convert a kernel VA into a HYP VA. * reg: VA to be converted. * * This generates the following sequences: * - High mask: * and x0, x0, #HYP_PAGE_OFFSET_HIGH_MASK * nop * - Low mask: * and x0, x0, #HYP_PAGE_OFFSET_HIGH_MASK * and x0, x0, #HYP_PAGE_OFFSET_LOW_MASK * - VHE: * nop * nop * * The "low mask" version works because the mask is a strict subset of * the "high mask", hence performing the first mask for nothing. * Should be completely invisible on any viable CPU. */ .macro kern_hyp_va reg alternative_if_not ARM64_HAS_VIRT_HOST_EXTN and \reg, \reg, #HYP_PAGE_OFFSET_HIGH_MASK alternative_else_nop_endif alternative_if ARM64_HYP_OFFSET_LOW and \reg, \reg, #HYP_PAGE_OFFSET_LOW_MASK alternative_else_nop_endif .endm #else #include #include #include #include #include static inline unsigned long __kern_hyp_va(unsigned long v) { asm volatile(ALTERNATIVE("and %0, %0, %1", "nop", ARM64_HAS_VIRT_HOST_EXTN) : "+r" (v) : "i" (HYP_PAGE_OFFSET_HIGH_MASK)); asm volatile(ALTERNATIVE("nop", "and %0, %0, %1", ARM64_HYP_OFFSET_LOW) : "+r" (v) : "i" (HYP_PAGE_OFFSET_LOW_MASK)); 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(void *from, void *to, phys_addr_t); 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); phys_addr_t kvm_get_idmap_start(void); int kvm_mmu_init(void); void kvm_clear_hyp_idmap(void); #define kvm_set_pte(ptep, pte) set_pte(ptep, pte) #define kvm_set_pmd(pmdp, pmd) set_pmd(pmdp, pmd) 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 void kvm_set_s2pte_readonly(pte_t *pte) { pteval_t pteval; unsigned long tmp; asm volatile("// kvm_set_s2pte_readonly\n" " prfm pstl1strm, %2\n" "1: ldxr %0, %2\n" " and %0, %0, %3 // clear PTE_S2_RDWR\n" " orr %0, %0, %4 // set PTE_S2_RDONLY\n" " stxr %w1, %0, %2\n" " cbnz %w1, 1b\n" : "=&r" (pteval), "=&r" (tmp), "+Q" (pte_val(*pte)) : "L" (~PTE_S2_RDWR), "L" (PTE_S2_RDONLY)); } static inline bool kvm_s2pte_readonly(pte_t *pte) { return (pte_val(*pte) & PTE_S2_RDWR) == PTE_S2_RDONLY; } static inline void kvm_set_s2pmd_readonly(pmd_t *pmd) { kvm_set_s2pte_readonly((pte_t *)pmd); } static inline bool kvm_s2pmd_readonly(pmd_t *pmd) { return kvm_s2pte_readonly((pte_t *)pmd); } 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_sys_reg(vcpu, SCTLR_EL1) & 0b101) == 0b101; } static inline void __coherent_cache_guest_page(struct kvm_vcpu *vcpu, kvm_pfn_t pfn, unsigned long size, bool ipa_uncached) { void *va = page_address(pfn_to_page(pfn)); kvm_flush_dcache_to_poc(va, size); if (!icache_is_aliasing()) { /* PIPT */ flush_icache_range((unsigned long)va, (unsigned long)va + size); } else if (!icache_is_aivivt()) { /* non ASID-tagged VIVT */ /* any kind of VIPT cache */ __flush_icache_all(); } } static inline void __kvm_flush_dcache_pte(pte_t pte) { 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) { 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) { 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(); } 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; /* * 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])); merged_hyp_pgd[0] = __pgd(__pa(hyp_pgd) | 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])); merged_hyp_pgd[idmap_idx] = __pgd(__pa(boot_hyp_pgd) | PMD_TYPE_TABLE); } static inline unsigned int kvm_get_vmid_bits(void) { int reg = read_system_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; } #ifdef CONFIG_HARDEN_BRANCH_PREDICTOR #include static inline void *kvm_get_hyp_vector(void) { struct bp_hardening_data *data = arm64_get_bp_hardening_data(); void *vect = kvm_ksym_ref(__kvm_hyp_vector); if (data->fn) { vect = __bp_harden_hyp_vecs_start + data->hyp_vectors_slot * SZ_2K; if (!cpus_have_const_cap(ARM64_HAS_VIRT_HOST_EXTN)) vect = lm_alias(vect); } return vect; } static inline int kvm_map_vectors(void) { return create_hyp_mappings(kvm_ksym_ref(__bp_harden_hyp_vecs_start), kvm_ksym_ref(__bp_harden_hyp_vecs_end), PAGE_HYP_EXEC); } #else static inline void *kvm_get_hyp_vector(void) { return 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 #endif /* __ASSEMBLY__ */ #endif /* __ARM64_KVM_MMU_H__ */