> This page is for Confidential Virtual Machines, version Dev (default).
> For other versions, use one of these documentation indexes:
> - Dev (default): https://docs.nvidia.com/confidential-computing/virtual-machines/dev/llms.txt

> For clean Markdown of any page, append .md to the page URL.
> For a complete documentation index, see https://docs.nvidia.com/confidential-computing/llms.txt.
> For AI client integration (Claude Code, Cursor, etc.), connect to the MCP server at https://docs.nvidia.com/confidential-computing/_mcp/server.

# Trust and Threat Model

> Understand the trusted components, responsibilities, mitigated threats, and limits of a confidential VM with NVIDIA Hopper or Blackwell GPUs.

A confidential VM (CVM) with NVIDIA GPUs protects a tenant's code, models, secrets, and data while they are in use, within the supported platform's threat model.
The CPU trusted execution environment (TEE) isolates the VM from privileged host software, and GPU Confidential Computing extends protection to the attached GPUs and supported communication paths.

The tenant, or CVM owner, controls the software inside the guest and decides which platform and software states to trust.
The infrastructure owner operates the host and provisions GPUs without needing access to the tenant's protected contents.
This page explains what that separation protects and which dependencies remain trusted.

## Scope and GPU Modes

The CPU TEE is provided by [Intel TDX](https://www.intel.com/content/www/us/en/developer/tools/trust-domain-extensions/documentation.html) or [AMD SEV-SNP](https://docs.amd.com/v/u/en-US/SEV-SNP-strengthening-vm-isolation-with-integrity-protection-and-more); its protections and exclusions follow the CPU vendor's threat model.
GPU protections depend on the GPU architecture, security mode, firmware, and driver versions.
Use [Supported Platforms](/confidential-computing/virtual-machines/supported-platforms) to identify validated configurations.

The GPU modes covered by this documentation differ in how they protect communication:

| Configuration                                 | CPU-to-GPU traffic | GPU-to-GPU traffic      |
| --------------------------------------------- | ------------------ | ----------------------- |
| Single-GPU CC mode, Hopper or Blackwell       | Encrypted          | Not applicable          |
| Multi-GPU CC mode, Blackwell                  | Encrypted          | Encrypted over NVLink   |
| Multi-GPU Protected PCIe (PPCIe) mode, Hopper | Encrypted          | Unencrypted over NVLink |

The [NVIDIA Secure AI whitepaper](https://docs.nvidia.com/nvidia-secure-ai-with-blackwell-and-hopper-gpus-whitepaper.pdf) describes these modes and their interconnect protections.
For Hopper PPCIe, the unencrypted NVLink path means that the assessment must also account for protection of the fabric, including NVSwitch and physical access.
CPU-to-GPU encryption alone does not establish confidentiality on that path.

## Trust and Responsibilities

These are functional roles; one organization can fill several roles.
In a deployment protecting a model owner's intellectual property, the model owner can act as the tenant.

| Party                                         | Controls or provides                                                                          | Responsibility or trust dependency                                                                                                             |
| --------------------------------------------- | --------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------- |
| Tenant / CVM owner                            | Guest OS, NVIDIA guest driver, CUDA stack, workload, protected assets, and attestation policy | Approves and secures guest software and administrative access; decides when secrets can be released.                                           |
| Infrastructure owner / cloud service provider | Host OS, hypervisor, GPU assignment, platform management, power, and scheduling               | Provisions and operates the platform. Host administration is treated as potentially malicious; availability remains dependent on the operator. |
| CPU vendor                                    | CPU hardware, TDX module or SEV-SNP firmware, and CPU attestation                             | Supplies VM isolation and CPU evidence within the vendor's threat model.                                                                       |
| NVIDIA                                        | GPU hardware, root of trust, signed firmware, guest driver, and attestation reference values  | Supplies GPU isolation, protected communication, and GPU evidence. NVIDIA does not approve the tenant's workload.                              |
| OEM / system integrator                       | Server platform and firmware integration                                                      | Integrates a supported configuration; platform dependencies must be evaluated against the CPU and GPU security requirements.                   |
| Verifier and key-release service operators    | Evidence appraisal, secret storage, and release-policy enforcement                            | Apply the tenant's policy and deliver secrets to the approved recipient. These services and their policy administrators remain trusted.        |

An end user of a tenant's service supplies inputs and receives outputs.
The CVM boundary does not isolate that user's data from the tenant or from software the tenant runs.

## Runtime Trust Boundary

The trusted computing base (TCB) comprises the components whose correct behavior is required to protect the workload:

* **CPU TEE:** CPU hardware and the security module or firmware that isolate private VM memory and CPU state.
* **Guest software:** Guest firmware, kernel, NVIDIA driver, CUDA libraries, workload, and any software or administrators with access to protected assets inside the guest.
* **GPU:** GPU hardware, its root of trust, and NVIDIA-signed firmware enforcing the selected mode.
* **Attestation and key services:** The verifier, its reference values and policies, and services that hold or release secrets, even when they run outside the CVM.

The host OS, hypervisor, virtual machine monitor, and other tenants are outside this runtime trust boundary.
Host management access through BIOS/UEFI or the baseboard management controller (BMC) does not make those interfaces trusted recipients of workload data.
Their permitted access and the fabric assumptions depend on the selected platform and GPU mode.

Each GPU is assigned whole to one CVM.
Within GPU memory, hardware access controls protect plaintext data; GPU memory encryption is not the protection mechanism.
The guest driver establishes a protected session with each GPU.
In the bounce-buffer path, shared CPU memory carries ciphertext between the guest and GPU, while private VM memory remains protected by the CPU TEE.

Trust and measurement coverage are distinct: guest software remains trusted even when a particular attestation flow does not measure every component.
The tenant must establish how its boot and workload-loading process authenticates the software and configuration that receive secrets.

## Threats and Mitigations

The following protections assume a validated configuration and a tenant policy that accepts the actual CPU, GPU, software, and security mode.

| Threat or access path                                                             | Protection                                                                                                                                         | Remaining condition or limit                                                                                                           |
| --------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------- |
| Host administrator or another tenant attempts to read or alter workload memory    | The CPU TEE isolates private VM state; GPU access controls and protected sessions restrict access to GPU state.                                    | Guest administrators and software inside the CVM remain trusted.                                                                       |
| An adversary observes, modifies, or replays protected CPU-to-GPU traffic          | Authenticated encryption protects payloads; session counters detect replay and keys rotate before counter exhaustion.                              | This does not extend encryption to Hopper PPCIe's NVLink traffic or to unrelated network and storage paths.                            |
| The platform supplies unapproved or older GPU firmware                            | GPU secure boot requires NVIDIA-signed firmware; attestation allows the verifier to appraise identity, measurements, mode, and certificate status. | A valid signature alone does not establish that a firmware version is acceptable. The tenant's policy must reject disallowed versions. |
| An administrator uses GPU management or debug interfaces to inspect workload data | In CC-On mode, management paths expose limited health information, JTAG is disabled, and performance counters are blocked.                         | CC-DevTools permits profiling access and must be excluded from a production policy that requires these restrictions.                   |
| A subsequent tenant attempts to recover data from a previous GPU session          | Session keys are ephemeral, and GPU reset and teardown mechanisms clear protected state.                                                           | Follow the supported GPU reset and reassignment lifecycle; stopping a workload is not a substitute for that lifecycle.                 |

## Attestation and Secret Release

The infrastructure owner selects the platform and assigns GPUs; the tenant decides whether to trust the resulting environment.
Before releasing model-decryption keys or other secrets, the tenant's verification and release flow must:

1. Verify CPU evidence against the tenant's policy for the CPU TEE and guest launch state.
2. Verify evidence for every assigned GPU, including identity, firmware measurements, security mode, reference values, and certificate status.
3. Establish that the approved guest software and configuration will receive the secrets, using the deployment's authenticated boot and workload-loading mechanisms.
4. Release secrets over a protected channel to that approved recipient only when all required checks succeed.

A successful GPU attestation does not validate the CPU TEE or the tenant's workload.
Likewise, CPU evidence alone does not establish the state of the attached GPUs.
The release policy must cover both and reject configurations that do not meet the tenant's requirements.

In the documented deployment flow, a user in the CVM sets the GPU ready state after successful attestation.
Attestation does not set that state automatically, and the ready state itself is not evidence that the tenant's release policy has been satisfied.
Refer to [Attesting the GPU](/confidential-computing/virtual-machines/deployment-guide/attest) for the procedure.

## Limits and Exclusions

* **Tenant software and policy:** Vulnerabilities, malicious guest code, permissive release policies, sensitive logging, and permitted debugging can expose protected assets. Attestation does not establish that approved code is free of vulnerabilities.
* **Availability:** The infrastructure owner can stop the CVM, interrupt networking, detach devices, or remove power. Confidential Computing does not guarantee service availability against that operator.
* **Physical attacks and side channels:** Invasive package probing and fault injection are outside this GPU threat model. CPU side-channel coverage follows the CPU vendor's model. Interconnect protection must be assessed for the selected GPU mode.
* **Network, storage, and other devices:** Protect data that leaves the CVM and its assigned GPUs separately, including network connections and stored artifacts. Do not infer protection for another device from GPU attestation.
* **GPU sharing and unsupported paths:** This model assumes whole-GPU assignment to one CVM. MIG, MPS, and GPUDirect RDMA are not supported in the CC configurations described here; consult the supported configuration documentation as capabilities evolve.
* **Trusted-component vulnerabilities:** CPU or GPU security flaws can affect the boundary. Track vendor advisories, update affected components, and revise accepted reference values and security versions as required.

## Related Topics

* [Deployment Guide](/confidential-computing/virtual-machines/deployment-guide): Configure the host, guest, and GPUs.
* [Configuring the GPUs](/confidential-computing/virtual-machines/deployment-guide/gpu-mode): Select and activate the GPU mode.
* [NVIDIA Attestation](https://docs.nvidia.com/attestation/): Evidence verification, reference values, and attestation services.