diff --git a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h index 81a2c9c9450a..b8e47a47c1e6 100644 --- a/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h +++ b/arch/arm64/kvm/hyp/include/nvhe/mem_protect.h @@ -74,6 +74,9 @@ int __pkvm_guest_share_host(struct pkvm_hyp_vcpu *hyp_vcpu, u64 ipa); int __pkvm_guest_unshare_host(struct pkvm_hyp_vcpu *hyp_vcpu, u64 ipa); int __pkvm_guest_relinquish_to_host(struct pkvm_hyp_vcpu *vcpu, u64 ipa, u64 *ppa); +int __pkvm_install_ioguard_page(struct pkvm_hyp_vcpu *hyp_vcpu, u64 ipa); +int __pkvm_remove_ioguard_page(struct pkvm_hyp_vcpu *hyp_vcpu, u64 ipa); +bool __pkvm_check_ioguard_page(struct pkvm_hyp_vcpu *hyp_vcpu); bool addr_is_memory(phys_addr_t phys); int host_stage2_idmap_locked(phys_addr_t addr, u64 size, enum kvm_pgtable_prot prot); diff --git a/arch/arm64/kvm/hyp/nvhe/mem_protect.c b/arch/arm64/kvm/hyp/nvhe/mem_protect.c index 6c49d9d691ea..ea87f5fd4cde 100644 --- a/arch/arm64/kvm/hyp/nvhe/mem_protect.c +++ b/arch/arm64/kvm/hyp/nvhe/mem_protect.c @@ -1823,3 +1823,103 @@ unlock: return ret; } + +/* Replace this with something more structured once day */ +#define MMIO_NOTE (('M' << 24 | 'M' << 16 | 'I' << 8 | 'O') << 1) + +static bool __check_ioguard_page(struct pkvm_hyp_vcpu *hyp_vcpu, u64 ipa) +{ + struct pkvm_hyp_vm *vm = pkvm_hyp_vcpu_to_hyp_vm(hyp_vcpu); + kvm_pte_t pte; + u32 level; + int ret; + + ret = kvm_pgtable_get_leaf(&vm->pgt, ipa, &pte, &level); + if (ret) + return false; + + /* Must be a PAGE_SIZE mapping with our annotation */ + return (BIT(ARM64_HW_PGTABLE_LEVEL_SHIFT(level)) == PAGE_SIZE && + pte == MMIO_NOTE); +} + +int __pkvm_install_ioguard_page(struct pkvm_hyp_vcpu *hyp_vcpu, u64 ipa) +{ + struct pkvm_hyp_vm *vm = pkvm_hyp_vcpu_to_hyp_vm(hyp_vcpu); + kvm_pte_t pte; + u32 level; + int ret; + + if (!test_bit(KVM_ARCH_FLAG_MMIO_GUARD, &vm->kvm.arch.flags)) + return -EINVAL; + + if (ipa & ~PAGE_MASK) + return -EINVAL; + + guest_lock_component(vm); + + ret = kvm_pgtable_get_leaf(&vm->pgt, ipa, &pte, &level); + if (ret) + goto unlock; + + if (pte && BIT(ARM64_HW_PGTABLE_LEVEL_SHIFT(level)) == PAGE_SIZE) { + /* + * Already flagged as MMIO, let's accept it, and fail + * otherwise + */ + if (pte != MMIO_NOTE) + ret = -EBUSY; + + goto unlock; + } + + ret = kvm_pgtable_stage2_annotate(&vm->pgt, ipa, PAGE_SIZE, + &hyp_vcpu->vcpu.arch.pkvm_memcache, + MMIO_NOTE); + +unlock: + guest_unlock_component(vm); + return ret; +} + +int __pkvm_remove_ioguard_page(struct pkvm_hyp_vcpu *hyp_vcpu, u64 ipa) +{ + struct pkvm_hyp_vm *vm = pkvm_hyp_vcpu_to_hyp_vm(hyp_vcpu); + + if (!test_bit(KVM_ARCH_FLAG_MMIO_GUARD, &vm->kvm.arch.flags)) + return -EINVAL; + + guest_lock_component(vm); + + if (__check_ioguard_page(hyp_vcpu, ipa)) + WARN_ON(kvm_pgtable_stage2_unmap(&vm->pgt, + ALIGN_DOWN(ipa, PAGE_SIZE), PAGE_SIZE)); + + guest_unlock_component(vm); + return 0; +} + +bool __pkvm_check_ioguard_page(struct pkvm_hyp_vcpu *hyp_vcpu) +{ + struct pkvm_hyp_vm *vm = pkvm_hyp_vcpu_to_hyp_vm(hyp_vcpu); + u64 ipa, end; + bool ret; + + if (!kvm_vcpu_dabt_isvalid(&hyp_vcpu->vcpu)) + return false; + + if (!test_bit(KVM_ARCH_FLAG_MMIO_GUARD, &vm->kvm.arch.flags)) + return true; + + ipa = kvm_vcpu_get_fault_ipa(&hyp_vcpu->vcpu); + ipa |= kvm_vcpu_get_hfar(&hyp_vcpu->vcpu) & FAR_MASK; + end = ipa + kvm_vcpu_dabt_get_as(&hyp_vcpu->vcpu) - 1; + + guest_lock_component(vm); + ret = __check_ioguard_page(hyp_vcpu, ipa); + if ((end & PAGE_MASK) != (ipa & PAGE_MASK)) + ret &= __check_ioguard_page(hyp_vcpu, end); + guest_unlock_component(vm); + + return ret; +}