/* 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/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
*
* 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 <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 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 <asm/pgalloc.h>
#include <asm/cache.h>
#include <asm/cacheflush.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
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 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))
static inline bool kvm_page_empty(void *ptr)
{
struct page *ptr_page = virt_to_page(ptr);
return page_count(ptr_page) == 1;
}
#include <asm/stage2_pgtable.h>
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)
#define kvm_set_pud(pudp, pud) set_pud(pudp, pud)
#define kvm_pfn_pte(pfn, prot) pfn_pte(pfn, prot)
#define kvm_pfn_pmd(pfn, prot) pfn_pmd(pfn, prot)
#define kvm_pfn_pud(pfn, prot) pfn_pud(pfn, prot)
#define kvm_pud_pfn(pud) pud_pfn(pud)
#define kvm_pmd_mkhuge(pmd) pmd_mkhuge(pmd)
#define kvm_pud_mkhuge(pud) pud_mkhuge(pud)
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 pud_t kvm_s2pud_mkwrite(pud_t pud)
{
pud_val(pud) |= PUD_S2_RDWR;
return pud;
}
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 pud_t kvm_s2pud_mkexec(pud_t pud)
{
pud_val(pud) &= ~PUD_S2_XN;
return pud;
}
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 void kvm_set_s2pud_readonly(pud_t *pudp)
{
kvm_set_s2pte_readonly((pte_t *)pudp);
}
static inline bool kvm_s2pud_readonly(pud_t *pudp)
{
return kvm_s2pte_readonly((pte_t *)pudp);
}
static inline bool kvm_s2pud_exec(pud_t *pudp)
{
return !(READ_ONCE(pud_val(*pudp)) & PUD_S2_XN);
}
static inline pud_t kvm_s2pud_mkyoung(pud_t pud)
{
return pud_mkyoung(pud);
}
static inline bool kvm_s2pud_young(pud_t pud)
{
return pud_young(pud);
}
#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 <asm/mmu.h>
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) && data->fn) {
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)) {
__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)
/*
* Get the magic number 'x' for VTTBR:BADDR of this KVM instance.
* With v8.2 LVA extensions, 'x' should be a minimum of 6 with
* 52bit IPS.
*/
static inline int arm64_vttbr_x(u32 ipa_shift, u32 levels)
{
int x = ARM64_VTTBR_X(ipa_shift, levels);
return (IS_ENABLED(CONFIG_ARM64_PA_BITS_52) && x < 6) ? 6 : x;
}
static inline u64 vttbr_baddr_mask(u32 ipa_shift, u32 levels)
{
unsigned int x = arm64_vttbr_x(ipa_shift, levels);
return GENMASK_ULL(PHYS_MASK_SHIFT - 1, x);
}
static inline u64 kvm_vttbr_baddr_mask(struct kvm *kvm)
{
return vttbr_baddr_mask(kvm_phys_shift(kvm), kvm_stage2_levels(kvm));
}
static __always_inline u64 kvm_get_vttbr(struct kvm *kvm)
{
struct kvm_vmid *vmid = &kvm->arch.vmid;
u64 vmid_field, baddr;
u64 cnp = system_supports_cnp() ? VTTBR_CNP_BIT : 0;
baddr = kvm->arch.pgd_phys;
vmid_field = (u64)vmid->vmid << VTTBR_VMID_SHIFT;
return kvm_phys_to_vttbr(baddr) | vmid_field | cnp;
}
#endif /* __ASSEMBLY__ */
#endif /* __ARM64_KVM_MMU_H__ */
