Commit Message
Isaku Yamahata
Feb. 26, 2024, 8:26 a.m. UTC
From: Isaku Yamahata <isaku.yamahata@intel.com> TDX allows to extned memory measurement with the initial memory. Define new subcommand, KVM_TDX_EXTEND_MEMORY, of VM-scoped KVM_MEMORY_ENCRYPT_OP. it extends memory measurement of the TDX guest. The memory region must be populated with KVM_MEMORY_MAPPING command. Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> --- v19: - newly added - Split KVM_TDX_INIT_MEM_REGION into only extension function --- arch/x86/include/uapi/asm/kvm.h | 1 + arch/x86/kvm/vmx/tdx.c | 64 +++++++++++++++++++++++++++++++++ 2 files changed, 65 insertions(+)
diff --git a/arch/x86/include/uapi/asm/kvm.h b/arch/x86/include/uapi/asm/kvm.h index 4000a2e087a8..34167404020c 100644 --- a/arch/x86/include/uapi/asm/kvm.h +++ b/arch/x86/include/uapi/asm/kvm.h @@ -572,6 +572,7 @@ enum kvm_tdx_cmd_id { KVM_TDX_CAPABILITIES = 0, KVM_TDX_INIT_VM, KVM_TDX_INIT_VCPU, + KVM_TDX_EXTEND_MEMORY, KVM_TDX_CMD_NR_MAX, }; diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c index 8cf6e5dab3e9..3cfba63a7762 100644 --- a/arch/x86/kvm/vmx/tdx.c +++ b/arch/x86/kvm/vmx/tdx.c @@ -1339,6 +1339,67 @@ void tdx_flush_tlb_current(struct kvm_vcpu *vcpu) tdx_track(vcpu->kvm); } +static int tdx_extend_memory(struct kvm *kvm, struct kvm_tdx_cmd *cmd) +{ + struct kvm_tdx *kvm_tdx = to_kvm_tdx(kvm); + struct kvm_memory_mapping mapping; + struct tdx_module_args out; + bool extended = false; + int idx, ret = 0; + gpa_t gpa; + u64 err; + int i; + + /* Once TD is finalized, the initial guest memory is fixed. */ + if (is_td_finalized(kvm_tdx)) + return -EINVAL; + + if (cmd->flags) + return -EINVAL; + + if (copy_from_user(&mapping, (void __user *)cmd->data, sizeof(mapping))) + return -EFAULT; + + /* Sanity check */ + if (mapping.source || !mapping.nr_pages || + mapping.nr_pages & GENMASK_ULL(63, 63 - PAGE_SHIFT) || + mapping.base_gfn + (mapping.nr_pages << PAGE_SHIFT) <= mapping.base_gfn || + !kvm_is_private_gpa(kvm, mapping.base_gfn) || + !kvm_is_private_gpa(kvm, mapping.base_gfn + (mapping.nr_pages << PAGE_SHIFT))) + return -EINVAL; + + idx = srcu_read_lock(&kvm->srcu); + while (mapping.nr_pages) { + if (signal_pending(current)) { + ret = -ERESTARTSYS; + break; + } + + if (need_resched()) + cond_resched(); + + gpa = gfn_to_gpa(mapping.base_gfn); + for (i = 0; i < PAGE_SIZE; i += TDX_EXTENDMR_CHUNKSIZE) { + err = tdh_mr_extend(kvm_tdx->tdr_pa, gpa + i, &out); + if (err) { + ret = -EIO; + break; + } + } + mapping.base_gfn++; + mapping.nr_pages--; + extended = true; + } + srcu_read_unlock(&kvm->srcu, idx); + + if (extended && mapping.nr_pages > 0) + ret = -EAGAIN; + if (copy_to_user((void __user *)cmd->data, &mapping, sizeof(mapping))) + ret = -EFAULT; + + return ret; +} + int tdx_vm_ioctl(struct kvm *kvm, void __user *argp) { struct kvm_tdx_cmd tdx_cmd; @@ -1358,6 +1419,9 @@ int tdx_vm_ioctl(struct kvm *kvm, void __user *argp) case KVM_TDX_INIT_VM: r = tdx_td_init(kvm, &tdx_cmd); break; + case KVM_TDX_EXTEND_MEMORY: + r = tdx_extend_memory(kvm, &tdx_cmd); + break; default: r = -EINVAL; goto out;