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Diffstat (limited to '')
| -rw-r--r-- | arch/arm64/include/asm/kvm_mmu.h | 302 |
1 files changed, 302 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h new file mode 100644 index 000000000..778408108 --- /dev/null +++ b/arch/arm64/include/asm/kvm_mmu.h @@ -0,0 +1,302 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2012,2013 - ARM Ltd + * Author: Marc Zyngier <marc.zyngier@arm.com> + */ + +#ifndef __ARM64_KVM_MMU_H__ +#define __ARM64_KVM_MMU_H__ + +#include <asm/page.h> +#include <asm/memory.h> +#include <asm/mmu.h> +#include <asm/cpufeature.h> + +/* + * 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 + * + * 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 <asm/alternative.h> + +/* + * 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 ARM64_ALWAYS_SYSTEM, 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 + +/* + * Convert a hypervisor VA to a PA + * reg: hypervisor address to be converted in place + * tmp: temporary register + */ +.macro hyp_pa reg, tmp + ldr_l \tmp, hyp_physvirt_offset + add \reg, \reg, \tmp +.endm + +/* + * Convert a hypervisor VA to a kernel image address + * reg: hypervisor address to be converted in place + * tmp: temporary register + * + * The actual code generation takes place in kvm_get_kimage_voffset, and + * the instructions below are only there to reserve the space and + * perform the register allocation (kvm_get_kimage_voffset uses the + * specific registers encoded in the instructions). + */ +.macro hyp_kimg_va reg, tmp + /* Convert hyp VA -> PA. */ + hyp_pa \reg, \tmp + + /* Load kimage_voffset. */ +alternative_cb ARM64_ALWAYS_SYSTEM, kvm_get_kimage_voffset + movz \tmp, #0 + movk \tmp, #0, lsl #16 + movk \tmp, #0, lsl #32 + movk \tmp, #0, lsl #48 +alternative_cb_end + + /* Convert PA -> kimg VA. */ + add \reg, \reg, \tmp +.endm + +#else + +#include <linux/pgtable.h> +#include <asm/pgalloc.h> +#include <asm/cache.h> +#include <asm/cacheflush.h> +#include <asm/mmu_context.h> +#include <asm/kvm_host.h> + +void kvm_update_va_mask(struct alt_instr *alt, + __le32 *origptr, __le32 *updptr, int nr_inst); +void kvm_compute_layout(void); +void kvm_apply_hyp_relocations(void); + +#define __hyp_pa(x) (((phys_addr_t)(x)) + hyp_physvirt_offset) + +static __always_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", + ARM64_ALWAYS_SYSTEM, + kvm_update_va_mask) + : "+r" (v)); + return v; +} + +#define kern_hyp_va(v) ((typeof(v))(__kern_hyp_va((unsigned long)(v)))) + +/* + * We currently support using a VM-specified IPA size. For backward + * compatibility, the default IPA size is fixed to 40bits. + */ +#define KVM_PHYS_SHIFT (40) + +#define kvm_phys_shift(kvm) VTCR_EL2_IPA(kvm->arch.vtcr) +#define kvm_phys_size(kvm) (_AC(1, ULL) << kvm_phys_shift(kvm)) +#define kvm_phys_mask(kvm) (kvm_phys_size(kvm) - _AC(1, ULL)) + +#include <asm/kvm_pgtable.h> +#include <asm/stage2_pgtable.h> + +int kvm_share_hyp(void *from, void *to); +void kvm_unshare_hyp(void *from, void *to); +int create_hyp_mappings(void *from, void *to, enum kvm_pgtable_prot prot); +int __create_hyp_mappings(unsigned long start, unsigned long size, + unsigned long phys, enum kvm_pgtable_prot prot); +int hyp_alloc_private_va_range(size_t size, unsigned long *haddr); +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_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu); +void kvm_free_stage2_pgd(struct kvm_s2_mmu *mmu); +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); + +phys_addr_t kvm_mmu_get_httbr(void); +phys_addr_t kvm_get_idmap_vector(void); +int kvm_mmu_init(u32 *hyp_va_bits); + +static inline void *__kvm_vector_slot2addr(void *base, + enum arm64_hyp_spectre_vector slot) +{ + int idx = slot - (slot != HYP_VECTOR_DIRECT); + + return base + (idx * SZ_2K); +} + +struct kvm; + +#define kvm_flush_dcache_to_poc(a,l) \ + dcache_clean_inval_poc((unsigned long)(a), (unsigned long)(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(void *va, size_t size) +{ + /* + * 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(void *va, size_t size) +{ + if (icache_is_aliasing()) { + /* any kind of VIPT cache */ + icache_inval_all_pou(); + } else if (is_kernel_in_hyp_mode() || !icache_is_vpipt()) { + /* PIPT or VPIPT at EL2 (see comment in __kvm_tlb_flush_vmid_ipa) */ + icache_inval_pou((unsigned long)va, (unsigned long)va + size); + } +} + +void kvm_set_way_flush(struct kvm_vcpu *vcpu); +void kvm_toggle_cache(struct kvm_vcpu *vcpu, bool was_enabled); + +static inline unsigned int kvm_get_vmid_bits(void) +{ + int reg = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1); + + return get_vmid_bits(reg); +} + +/* + * 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; +} + +#define kvm_phys_to_vttbr(addr) phys_to_ttbr(addr) + +/* + * When this is (directly or indirectly) used on the TLB invalidation + * path, we rely on a previously issued DSB so that page table updates + * and VMID reads are correctly ordered. + */ +static __always_inline u64 kvm_get_vttbr(struct kvm_s2_mmu *mmu) +{ + struct kvm_vmid *vmid = &mmu->vmid; + u64 vmid_field, baddr; + u64 cnp = system_supports_cnp() ? VTTBR_CNP_BIT : 0; + + baddr = mmu->pgd_phys; + vmid_field = atomic64_read(&vmid->id) << VTTBR_VMID_SHIFT; + vmid_field &= VTTBR_VMID_MASK(kvm_arm_vmid_bits); + return kvm_phys_to_vttbr(baddr) | vmid_field | cnp; +} + +/* + * Must be called from hyp code running at EL2 with an updated VTTBR + * and interrupts disabled. + */ +static __always_inline void __load_stage2(struct kvm_s2_mmu *mmu, + struct kvm_arch *arch) +{ + write_sysreg(arch->vtcr, vtcr_el2); + write_sysreg(kvm_get_vttbr(mmu), vttbr_el2); + + /* + * ARM errata 1165522 and 1530923 require the actual execution of the + * above before we can switch to the EL1/EL0 translation regime used by + * the guest. + */ + asm(ALTERNATIVE("nop", "isb", ARM64_WORKAROUND_SPECULATIVE_AT)); +} + +static inline struct kvm *kvm_s2_mmu_to_kvm(struct kvm_s2_mmu *mmu) +{ + return container_of(mmu->arch, struct kvm, arch); +} +#endif /* __ASSEMBLY__ */ +#endif /* __ARM64_KVM_MMU_H__ */ |