1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
// Copyright (c) Microsoft Corporation.
// Licensed under the MIT License.

//! UEFI Nvram variable services subsystem.
//!
//! Special care has been taken to keep all Hyper-V specific interfaces and
//! extensions in a separate layer from the underlying UEFI spec mandated
//! functionality.
//!
//! e.g: things like injecting various nvram vars related to secure boot, boot
//! order, etc... are not part of the UEFI spec, and are therefore implemented
//! _outside_ of the [`spec_services`] module.

pub use spec_services::NvramError;
pub use spec_services::NvramResult;
pub use spec_services::NvramServicesExt;
pub use spec_services::NvramSpecServices;

use crate::platform::nvram::VsmConfig;
use crate::UefiDevice;
use firmware_uefi_custom_vars::CustomVars;
use guestmem::GuestMemoryError;
use inspect::Inspect;
use std::borrow::Cow;
use std::fmt::Debug;
use thiserror::Error;
use uefi_nvram_storage::InspectableNvramStorage;
use uefi_specs::uefi::common::EfiStatus;
use uefi_specs::uefi::nvram::EfiVariableAttributes;
use zerocopy::AsBytes;

#[cfg(feature = "fuzzing")]
pub mod spec_services;
#[cfg(not(feature = "fuzzing"))]
mod spec_services;

#[derive(Debug, Error)]
pub enum NvramSetupError {
    #[error("could not query backing nvram storage")]
    BadNvramStorage(#[source] crate::platform::nvram::NvramStorageError),
    #[error("could not inject pre-boot var '{0}': {1:?}")]
    InjectPreBootVar(
        Cow<'static, ucs2::Ucs2LeSlice>,
        EfiStatus,
        #[source] Option<NvramError>,
    ),
    #[error("could not inject signature var '{0}': {1:?}")]
    InjectSigVar(
        Cow<'static, ucs2::Ucs2LeSlice>,
        EfiStatus,
        #[source] Option<NvramError>,
    ),
    #[error("could not inject custom var '{0}': {1:?}")]
    InjectCustomVar(String, EfiStatus, #[source] Option<NvramError>),
    #[error("custom variable name is not valid UCS-2")]
    CustomVarNotUcs2,
}

/// Implements Hyper-V specific nvram service interfaces, extensions, and
/// functionality, deferring to the underlying [`NvramSpecServices`] object to
/// implement any UEFI spec mandated nvram service functionality.
#[derive(Inspect)]
pub struct NvramServices {
    // Runtime glue
    #[inspect(skip)]
    vsm_config: Option<Box<dyn VsmConfig>>,

    // Sub-emulators
    #[inspect(flatten)]
    services: NvramSpecServices<Box<dyn InspectableNvramStorage>>,
}

impl NvramServices {
    pub async fn new(
        nvram_storage: Box<dyn InspectableNvramStorage>,
        custom_vars: CustomVars,
        secure_boot_enabled: bool,
        vsm_config: Option<Box<dyn VsmConfig>>,
        is_restoring: bool,
    ) -> Result<NvramServices, NvramSetupError> {
        let mut nvram = NvramServices {
            services: NvramSpecServices::new(nvram_storage),
            vsm_config,
        };

        if !is_restoring {
            nvram.inject_vars_on_first_boot(custom_vars).await?;
            nvram.inject_hyperv_vars().await?;
            nvram.setup_secure_boot(secure_boot_enabled).await?;
        }

        nvram.services.prepare_for_boot();

        Ok(nvram)
    }

    pub fn reset(&mut self) {
        self.services.reset();
        self.services.prepare_for_boot();
    }

    /// Check if this is the VM's first boot, and if so, inject various
    /// hard-coded and custom UEFI vars.
    async fn inject_vars_on_first_boot(
        &mut self,
        custom_vars: CustomVars,
    ) -> Result<(), NvramSetupError> {
        // "First boot" is marked by having no variables in nvram storage
        if !self
            .services
            .is_empty()
            .await
            .map_err(NvramSetupError::BadNvramStorage)?
        {
            return Ok(());
        }

        tracing::info!("No NVRAM variables (first boot). Loading in initial NVRAM values.");

        // Windows uses CurrentPolicy to protect secure boot policy
        tracing::trace!("Injecting 'CurrentPolicy'");
        {
            use uefi_specs::hyperv::nvram::vars::CURRENT_POLICY;

            let (vendor, name) = CURRENT_POLICY();
            const CURRENT_POLICY_AUTHENTICATED_MARKER: u8 = 0x02;
            let data = [CURRENT_POLICY_AUTHENTICATED_MARKER];
            let attr = EfiVariableAttributes::DEFAULT_ATTRIBUTES_TIME_BASED_AUTH;

            // because this variable is set with time based auth, it needs a
            // `EFI_VARIABLE_AUTHENTICATION_2`. fortunately, we are still in
            // pre-boot, which means it suffices to use a dummy header.
            let data = {
                let mut v = Vec::new();
                v.extend(uefi_specs::uefi::nvram::EFI_VARIABLE_AUTHENTICATION_2::DUMMY.as_bytes());
                v.extend(data);
                v
            };

            self.services
                .set_variable_ucs2(vendor, name, attr.into(), data.to_vec())
                .await
                .map_err(|(status, err)| {
                    NvramSetupError::InjectPreBootVar(name.into(), status, err)
                })?;
        }

        tracing::trace!("Updating 'SetupMode'");
        {
            use uefi_specs::uefi::nvram::vars::SETUP_MODE;
            let (_, name) = SETUP_MODE();

            self.services.update_setup_mode().await.map_err(|e| {
                NvramSetupError::InjectPreBootVar(
                    name.into(),
                    EfiStatus::DEVICE_ERROR,
                    Some(NvramError::NvramStorage(e)),
                )
            })?
        }

        self.inject_custom_vars(custom_vars).await?;

        Ok(())
    }

    async fn inject_hyperv_vars(&mut self) -> Result<(), NvramSetupError> {
        // Always inject these, in case the vmgs file was first booted RS1.86
        tracing::trace!("Injecting 'OsLoaderIndications'");
        {
            use uefi_specs::hyperv::nvram::vars::OS_LOADER_INDICATIONS;

            let (vendor, name) = OS_LOADER_INDICATIONS();
            let data = 0u32.as_bytes();
            let attr = EfiVariableAttributes::new().with_bootservice_access(true);

            self.services
                .set_variable_ucs2(vendor, name, attr.into(), data.to_vec())
                .await
                .map_err(|(status, err)| {
                    NvramSetupError::InjectPreBootVar(name.into(), status, err)
                })?;
        }

        tracing::trace!("Injecting 'OsLoaderIndicationsSupported'");
        {
            use uefi_specs::hyperv::nvram::vars::OS_LOADER_INDICATIONS_SUPPORTED;

            let (vendor, name) = OS_LOADER_INDICATIONS_SUPPORTED();
            // All VM versions capable of running the HCL support VSM
            let data = 1u32.as_bytes();
            let attr = EfiVariableAttributes::new().with_bootservice_access(true);

            self.services
                .set_variable_ucs2(vendor, name, attr.into(), data.to_vec())
                .await
                .map_err(|(status, err)| {
                    NvramSetupError::InjectPreBootVar(name.into(), status, err)
                })?;
        }

        Ok(())
    }

    async fn inject_custom_vars(&mut self, custom_vars: CustomVars) -> Result<(), NvramSetupError> {
        use firmware_uefi_custom_vars::CustomVar;
        use firmware_uefi_custom_vars::Sha256Digest;
        use firmware_uefi_custom_vars::Signature;
        use firmware_uefi_custom_vars::X509Cert;
        use uefi_nvram_specvars::signature_list::SignatureData;
        use uefi_nvram_specvars::signature_list::SignatureList;
        use uefi_specs::hyperv::nvram::vars::MSFT_SECURE_BOOT_PRODUCTION_GUID;
        use uefi_specs::uefi::nvram::EFI_VARIABLE_AUTHENTICATION_2;

        tracing::trace!(custom_vars = ?custom_vars.custom_vars, "custom uefi vars");

        // inject freeform custom vars first, as some may require an auth bypass
        for (name, CustomVar { guid, attr, value }) in custom_vars.custom_vars {
            tracing::trace!(%name, "Injecting custom var");

            // the value might need to be prepended with an auth header,
            // depending on what auth mode the variable is using.
            let value = {
                let attr = EfiVariableAttributes::from(attr);
                if attr.contains_unsupported_bits() {
                    return Err(NvramSetupError::InjectCustomVar(
                        name,
                        EfiStatus::INVALID_PARAMETER,
                        Some(NvramError::AttributeNonSpec),
                    ));
                }

                if attr.time_based_authenticated_write_access() {
                    let mut new_value = Vec::new();
                    // a dummy header needs to be present, even through no
                    // actual validation will be performed while nvram is still
                    // in SetupMode (i.e: until `pk` is injected).
                    new_value.extend(EFI_VARIABLE_AUTHENTICATION_2::DUMMY.as_bytes());
                    new_value.extend(value);
                    new_value
                } else {
                    value
                }
            };

            self.services
                .set_variable(guid, &name, attr, value)
                .await
                .map_err(|(status, err)| NvramSetupError::InjectCustomVar(name, status, err))?;
        }

        // inject structured signature vars
        if let Some(sigs) = custom_vars.signatures {
            use uefi_specs::linux::nvram::vars as linux_vars;
            use uefi_specs::uefi::nvram::vars as uefi_vars;

            // `dbDefault` is a read-only copy of the initial `db`
            let dbdefault_sig = sigs.db.clone();

            // for each of the signatures, construct the variable payload
            // (in the form of a signature list), and inject it into nvram.
            #[rustfmt::skip]
            let sigs_loop = [
                (uefi_vars::KEK(),        sigs.kek,      EfiVariableAttributes::DEFAULT_ATTRIBUTES_TIME_BASED_AUTH),
                (uefi_vars::DB(),         sigs.db,       EfiVariableAttributes::DEFAULT_ATTRIBUTES_TIME_BASED_AUTH),
                (uefi_vars::DBX(),        sigs.dbx,      EfiVariableAttributes::DEFAULT_ATTRIBUTES_TIME_BASED_AUTH),
                // Two notes:
                //
                // 1. Why the `vec![]`? Well, while there can only ever be a
                //    single PK, it still ends up getting stored in a signature
                //    _list_, so we may as well reuse the existing logic (rather
                //    than having a special cased block just for PK).
                //
                // 2. pk _must_ be injected after kek, db, and dbx, as once pk
                //    is injected, nvram switches out of SetupMode, and requires
                //    non-dummy auth var headers to update those vars.
                (uefi_vars::PK(),         vec![sigs.pk], EfiVariableAttributes::DEFAULT_ATTRIBUTES_TIME_BASED_AUTH),
                (uefi_vars::DBDEFAULT(),  dbdefault_sig, EfiVariableAttributes::DEFAULT_ATTRIBUTES_VOLATILE),
                (linux_vars::MOK_LIST(),  sigs.moklist,  EfiVariableAttributes::DEFAULT_ATTRIBUTES),
                (linux_vars::MOK_LISTX(), sigs.moklistx, EfiVariableAttributes::DEFAULT_ATTRIBUTES),
            ];

            for ((vendor, name), sigs, attr) in sigs_loop {
                tracing::trace!(?name, "Injecting");

                let mut var_data: Vec<u8> = Vec::new();

                if attr.time_based_authenticated_write_access() {
                    // a dummy header needs to be present, even through no
                    // actual validation will be performed while nvram is still
                    // in SetupMode (i.e: until `pk` is injected).
                    var_data.extend(EFI_VARIABLE_AUTHENTICATION_2::DUMMY.as_bytes());
                }

                for sig in sigs {
                    match sig {
                        Signature::X509(certs) => {
                            // x509 is weird, since every cert in the array
                            // actually ends up as a _separate_ signature list!
                            for X509Cert(data) in certs {
                                let sig_list = SignatureList::X509(SignatureData::new_x509(
                                    MSFT_SECURE_BOOT_PRODUCTION_GUID,
                                    Cow::Owned(data),
                                ));
                                sig_list.extend_as_spec_signature_list(&mut var_data);
                            }
                        }
                        Signature::Sha256(digests) => {
                            let sig_list = SignatureList::Sha256(
                                digests
                                    .into_iter()
                                    .map(|Sha256Digest(data)| {
                                        SignatureData::new_sha256(
                                            MSFT_SECURE_BOOT_PRODUCTION_GUID,
                                            Cow::Owned(data),
                                        )
                                    })
                                    .collect(),
                            );
                            sig_list.extend_as_spec_signature_list(&mut var_data);
                        }
                    }
                }

                if var_data.is_empty() {
                    continue;
                }

                self.services
                    .set_variable_ucs2(vendor, name, attr.into(), var_data)
                    .await
                    .map_err(|(status, err)| {
                        NvramSetupError::InjectSigVar(name.into(), status, err)
                    })?;
            }
        }

        Ok(())
    }

    /// Inject secure boot configuration vars.
    async fn setup_secure_boot(&mut self, enabled: bool) -> Result<(), NvramSetupError> {
        tracing::info!(enabled, "configuring secure boot");

        let data = if enabled { [0x01] } else { [0x00] };

        tracing::trace!("Injecting 'SecureBoot'");
        {
            use uefi_specs::uefi::nvram::vars::SECURE_BOOT;

            let (vendor, name) = SECURE_BOOT();

            // Older versions of OpenHCL (and Hyper-V, closed-source HCL, etc. ) may have created
            // a SecureBoot variable with the NV attribute, which doesn't match the UEFI spec.
            // Delete this variable (if it exists).
            let delete_attr = EfiVariableAttributes::new();
            let _ = self
                .services
                .set_variable_ucs2(vendor, name, delete_attr.into(), data.to_vec())
                .await;

            // TODO: For compatibility with older OpenHCL images that cannot handle a volatile
            // variable, we still need to create with NV for now.  Once the above variable
            // deletion code is deployed everywhere, replace with:
            // let attr = EfiVariableAttributes::DEFAULT_ATTRIBUTES_VOLATILE;
            let attr = EfiVariableAttributes::DEFAULT_ATTRIBUTES;
            self.services
                .set_variable_ucs2(vendor, name, attr.into(), data.to_vec())
                .await
                .map_err(|(status, err)| {
                    NvramSetupError::InjectPreBootVar(name.into(), status, err)
                })?;
        }

        tracing::trace!("Injecting 'SecureBootEnabled'");
        {
            use uefi_specs::hyperv::nvram::vars::SECURE_BOOT_ENABLE;

            let (vendor, name) = SECURE_BOOT_ENABLE();
            let attr = EfiVariableAttributes::DEFAULT_ATTRIBUTES;

            self.services
                .set_variable_ucs2(vendor, name, attr.into(), data.to_vec())
                .await
                .map_err(|(status, err)| {
                    NvramSetupError::InjectPreBootVar(name.into(), status, err)
                })?;
        }

        Ok(())
    }
}

impl UefiDevice {
    pub(crate) async fn nvram_handle_command(&mut self, desc_addr: u64) {
        use uefi_specs::hyperv::nvram::NvramCommandDescriptor;

        let mut desc: NvramCommandDescriptor = match self.gm.read_plain(desc_addr) {
            Ok(desc) => desc,
            Err(err) => {
                tracelimit::warn_ratelimited!(
                    error = &err as &dyn std::error::Error,
                    "Could not read NvramCommandDescriptor from guest memory",
                );
                return;
            }
        };

        let status = match self.handle_nvram_command_inner(desc_addr, desc).await {
            Ok(status) => status,
            Err(err) => {
                tracelimit::warn_ratelimited!(
                    error = &err as &dyn std::error::Error,
                    "Guest memory error while handling nvram command"
                );
                EfiStatus::DEVICE_ERROR
            }
        };

        // write back status into guest memory
        desc.status = status.into();

        if let Err(err) = self.gm.write_plain(desc_addr, &desc) {
            tracelimit::warn_ratelimited!(
                error = &err as &dyn std::error::Error,
                "Could not write NvramCommandDescriptor into guest memory",
            );
        }
    }

    async fn handle_nvram_command_inner(
        &mut self,
        desc_addr: u64,
        desc: uefi_specs::hyperv::nvram::NvramCommandDescriptor,
    ) -> Result<EfiStatus, GuestMemoryError> {
        use uefi_specs::hyperv::nvram::NvramCommand;
        use uefi_specs::hyperv::nvram::NvramVariableCommand;

        let command_addr = desc_addr + size_of_val(&desc) as u64;

        let (status, err) = match desc.command {
            NvramCommand::GET_VARIABLE => {
                let mut command: NvramVariableCommand = self.gm.read_plain(command_addr)?;

                let name = if command.name_address.get() != 0 {
                    let mut buf = vec![0; command.name_bytes as usize];
                    self.gm
                        .read_at(command.name_address.into(), buf.as_mut_slice())?;
                    Some(buf)
                } else {
                    None
                };

                let NvramResult(data, status, err) = self
                    .service
                    .nvram
                    .services
                    .uefi_get_variable(
                        name.as_deref(),
                        command.vendor_guid,
                        &mut command.attributes,
                        &mut command.data_bytes,
                        command.data_address.get() == 0,
                    )
                    .await;

                // writeback updated command struct
                self.gm.write_plain(command_addr, &command)?;

                // write any data to provided guest memory location
                // (bounds checking is performed within `nvram.get_variable`)
                if let Some(data) = data {
                    self.gm
                        .write_at(command.data_address.get(), data.as_bytes())?;
                }

                (status, err)
            }
            NvramCommand::SET_VARIABLE => {
                let command: NvramVariableCommand = self.gm.read_plain(command_addr)?;

                let name = if command.name_address.get() != 0 {
                    let mut buf = vec![0; command.name_bytes as usize];
                    self.gm
                        .read_at(command.name_address.into(), buf.as_mut_slice())?;
                    Some(buf)
                } else {
                    None
                };

                let data = if command.data_address.get() != 0 {
                    let mut buf = vec![0; command.data_bytes as usize];
                    self.gm
                        .read_at(command.data_address.into(), buf.as_mut_slice())?;
                    Some(buf)
                } else {
                    None
                };

                let NvramResult((), status, err) = self
                    .service
                    .nvram
                    .services
                    .uefi_set_variable(
                        name.as_deref(),
                        command.vendor_guid,
                        command.attributes,
                        command.data_bytes,
                        data,
                    )
                    .await;

                (status, err)
            }
            NvramCommand::GET_FIRST_VARIABLE_NAME | NvramCommand::GET_NEXT_VARIABLE_NAME => {
                let mut command: NvramVariableCommand = self.gm.read_plain(command_addr)?;

                let name = if desc.command == NvramCommand::GET_NEXT_VARIABLE_NAME {
                    if command.name_address.get() != 0 {
                        let mut buf = vec![0; command.name_bytes as usize];
                        self.gm
                            .read_at(command.name_address.into(), buf.as_mut_slice())?;
                        Some(buf)
                    } else {
                        None
                    }
                } else {
                    // If the command is GET_FIRST_VARIABLE_NAME, then we should
                    // ignore the name provided in the NvramVariableCommand
                    // struct, and just pass along a empty UTF-16 string to
                    // `get_next_variable`, which will fetch the first variable
                    // name (as specified by the official UEFI spec)
                    Some(vec![0, 0])
                };

                let NvramResult(data, status, err) = self
                    .service
                    .nvram
                    .services
                    .uefi_get_next_variable(
                        &mut command.name_bytes,
                        name.as_deref(),
                        command.vendor_guid,
                    )
                    .await;

                // write new name data to provided guest memory location
                // (bounds checking is performed within `nvram.get_next_variable`)
                if let Some((name, vendor)) = data {
                    command.vendor_guid = vendor;

                    self.gm
                        .write_at(command.name_address.get(), name.as_bytes())?;
                }

                // writeback updated command struct
                self.gm.write_at(command_addr, command.as_bytes())?;

                (status, err)
            }
            NvramCommand::QUERY_INFO => (EfiStatus::UNSUPPORTED, None),
            NvramCommand::SIGNAL_RUNTIME => {
                use uefi_specs::hyperv::nvram::NvramSignalRuntimeCommand;
                let command: NvramSignalRuntimeCommand = self.gm.read_plain(command_addr)?;

                if !command.flags.vsm_aware() {
                    if let Some(vsm) = &self.service.nvram.vsm_config {
                        tracelimit::info_ratelimited!("Revoking guest vsm");
                        vsm.revoke_guest_vsm()
                    }
                }
                self.service.nvram.services.exit_boot_services();

                (EfiStatus::SUCCESS, None)
            }
            NvramCommand::DEBUG_STRING => {
                let command: uefi_specs::hyperv::nvram::NvramDebugStringCommand =
                    self.gm.read_plain(command_addr)?;

                let mut data = vec![0u16; command.len as usize / 2];
                self.gm
                    .read_at(command.address.into(), data.as_bytes_mut())?;

                tracing::trace!(
                    target: "uefi-nvram-guest-debug",
                    data = %String::from_utf16_lossy(&data),
                    "nvram guest debug",
                );
                (EfiStatus::SUCCESS, None)
            }
            command => {
                tracelimit::warn_ratelimited!(?command, "unknown nvram command");
                (EfiStatus::UNSUPPORTED, None)
            }
        };

        // log any errors which may have occurred
        if let Some(err) = err {
            let err: &(dyn std::error::Error + 'static) = &err;
            tracelimit::warn_ratelimited!(
                command = ?desc.command,
                ?status,
                error = err,
                "nvram error"
            )
        }

        if status != EfiStatus::SUCCESS {
            tracing::trace!(?status, "nvram status");
        }

        Ok(status)
    }
}

mod save_restore {
    use super::*;
    use vmcore::save_restore::RestoreError;
    use vmcore::save_restore::SaveError;
    use vmcore::save_restore::SaveRestore;

    mod state {
        use crate::service::nvram::NvramSpecServices;
        use mesh::payload::Protobuf;
        use uefi_nvram_storage::InspectableNvramStorage;
        use vmcore::save_restore::SaveRestore;

        #[derive(Protobuf)]
        #[mesh(package = "firmware.uefi.nvram")]
        pub struct SavedState {
            #[mesh(1)]
            pub services:
                <NvramSpecServices<Box<dyn InspectableNvramStorage>> as SaveRestore>::SavedState,
        }
    }

    impl SaveRestore for NvramServices {
        type SavedState = state::SavedState;

        fn save(&mut self) -> Result<Self::SavedState, SaveError> {
            let NvramServices {
                vsm_config: _,
                services,
            } = self;

            let saved_state = state::SavedState {
                services: services.save()?,
            };

            Ok(saved_state)
        }

        fn restore(&mut self, state: Self::SavedState) -> Result<(), RestoreError> {
            let state::SavedState { services } = state;

            self.services.restore(services)?;

            Ok(())
        }
    }
}