diff options
| -rw-r--r-- | arch/arm64/include/asm/kvm_pgtable.h | 29 | ||||
| -rw-r--r-- | arch/arm64/kvm/hyp/pgtable.c | 89 |
2 files changed, 114 insertions, 4 deletions
diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h index eea2e2b0acaa..e1fed14aee17 100644 --- a/arch/arm64/include/asm/kvm_pgtable.h +++ b/arch/arm64/include/asm/kvm_pgtable.h @@ -95,6 +95,16 @@ enum kvm_pgtable_prot { #define PAGE_HYP_DEVICE (PAGE_HYP | KVM_PGTABLE_PROT_DEVICE) /** + * struct kvm_mem_range - Range of Intermediate Physical Addresses + * @start: Start of the range. + * @end: End of the range. + */ +struct kvm_mem_range { + u64 start; + u64 end; +}; + +/** * enum kvm_pgtable_walk_flags - Flags to control a depth-first page-table walk. * @KVM_PGTABLE_WALK_LEAF: Visit leaf entries, including invalid * entries. @@ -397,4 +407,23 @@ int kvm_pgtable_stage2_flush(struct kvm_pgtable *pgt, u64 addr, u64 size); int kvm_pgtable_walk(struct kvm_pgtable *pgt, u64 addr, u64 size, struct kvm_pgtable_walker *walker); +/** + * kvm_pgtable_stage2_find_range() - Find a range of Intermediate Physical + * Addresses with compatible permission + * attributes. + * @pgt: Page-table structure initialised by kvm_pgtable_stage2_init(). + * @addr: Address that must be covered by the range. + * @prot: Protection attributes that the range must be compatible with. + * @range: Range structure used to limit the search space at call time and + * that will hold the result. + * + * The offset of @addr within a page is ignored. An IPA is compatible with @prot + * iff its corresponding stage-2 page-table entry has default ownership and, if + * valid, is mapped with protection attributes identical to @prot. + * + * Return: 0 on success, negative error code on failure. + */ +int kvm_pgtable_stage2_find_range(struct kvm_pgtable *pgt, u64 addr, + enum kvm_pgtable_prot prot, + struct kvm_mem_range *range); #endif /* __ARM64_KVM_PGTABLE_H__ */ diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c index f4a514a2e7ae..dc6ef2cfe3eb 100644 --- a/arch/arm64/kvm/hyp/pgtable.c +++ b/arch/arm64/kvm/hyp/pgtable.c @@ -48,6 +48,8 @@ KVM_PTE_LEAF_ATTR_LO_S2_S2AP_W | \ KVM_PTE_LEAF_ATTR_HI_S2_XN) +#define KVM_PTE_LEAF_ATTR_S2_IGNORED GENMASK(58, 55) + #define KVM_INVALID_PTE_OWNER_MASK GENMASK(63, 56) #define KVM_MAX_OWNER_ID 1 @@ -77,15 +79,20 @@ static bool kvm_phys_is_valid(u64 phys) return phys < BIT(id_aa64mmfr0_parange_to_phys_shift(ID_AA64MMFR0_PARANGE_MAX)); } -static bool kvm_block_mapping_supported(u64 addr, u64 end, u64 phys, u32 level) +static bool kvm_level_supports_block_mapping(u32 level) { - u64 granule = kvm_granule_size(level); - /* * Reject invalid block mappings and don't bother with 4TB mappings for * 52-bit PAs. */ - if (level == 0 || (PAGE_SIZE != SZ_4K && level == 1)) + return !(level == 0 || (PAGE_SIZE != SZ_4K && level == 1)); +} + +static bool kvm_block_mapping_supported(u64 addr, u64 end, u64 phys, u32 level) +{ + u64 granule = kvm_granule_size(level); + + if (!kvm_level_supports_block_mapping(level)) return false; if (granule > (end - addr)) @@ -1053,3 +1060,77 @@ void kvm_pgtable_stage2_destroy(struct kvm_pgtable *pgt) pgt->mm_ops->free_pages_exact(pgt->pgd, pgd_sz); pgt->pgd = NULL; } + +#define KVM_PTE_LEAF_S2_COMPAT_MASK (KVM_PTE_LEAF_ATTR_S2_PERMS | \ + KVM_PTE_LEAF_ATTR_LO_S2_MEMATTR | \ + KVM_PTE_LEAF_ATTR_S2_IGNORED) + +static int stage2_check_permission_walker(u64 addr, u64 end, u32 level, + kvm_pte_t *ptep, + enum kvm_pgtable_walk_flags flag, + void * const arg) +{ + kvm_pte_t old_attr, pte = *ptep, *new_attr = arg; + + /* + * Compatible mappings are either invalid and owned by the page-table + * owner (whose id is 0), or valid with matching permission attributes. + */ + if (kvm_pte_valid(pte)) { + old_attr = pte & KVM_PTE_LEAF_S2_COMPAT_MASK; + if (old_attr != *new_attr) + return -EEXIST; + } else if (pte) { + return -EEXIST; + } + + return 0; +} + +int kvm_pgtable_stage2_find_range(struct kvm_pgtable *pgt, u64 addr, + enum kvm_pgtable_prot prot, + struct kvm_mem_range *range) +{ + kvm_pte_t attr; + struct kvm_pgtable_walker check_perm_walker = { + .cb = stage2_check_permission_walker, + .flags = KVM_PGTABLE_WALK_LEAF, + .arg = &attr, + }; + u64 granule, start, end; + u32 level; + int ret; + + ret = stage2_set_prot_attr(prot, &attr); + if (ret) + return ret; + attr &= KVM_PTE_LEAF_S2_COMPAT_MASK; + + for (level = pgt->start_level; level < KVM_PGTABLE_MAX_LEVELS; level++) { + granule = kvm_granule_size(level); + start = ALIGN_DOWN(addr, granule); + end = start + granule; + + if (!kvm_level_supports_block_mapping(level)) + continue; + + if (start < range->start || range->end < end) + continue; + + /* + * Check the presence of existing mappings with incompatible + * permissions within the current block range, and try one level + * deeper if one is found. + */ + ret = kvm_pgtable_walk(pgt, start, granule, &check_perm_walker); + if (ret != -EEXIST) + break; + } + + if (!ret) { + range->start = start; + range->end = end; + } + + return ret; +} |