[PATCH 1/3] libvirt: Introduce virDomainSetLaunchSecurityState public API

[Daniel P. Berrangé]

On Tue, Nov 30, 2021 at 04:51:58PM -0700, Jim Fehlig wrote:
> This API allows setting a launch secret within a guests's memory. The
> launch secret is created by the guest owner after retrieving and
> verifying the launch measurement with virDomainGetLaunchSecurityInfo.
> 
> The API uses virTypedParameter for input, allowing it to be expanded
> to support other confidential computing technologies. In the case of
> SEV, a basic guest launch workflow is described in the SEV API spec
> in section "1.3.1 Launch"
> 
> https://www.amd.com/system/files/TechDocs/55766_SEV-KM_API_Specification.pdf
> 
> Signed-off-by: Jim Fehlig <jfehlig at suse.com>
> ---
>  include/libvirt/libvirt-domain.h | 35 +++++++++++++++++++++
>  src/driver-hypervisor.h          |  7 +++++
>  src/libvirt-domain.c             | 52 ++++++++++++++++++++++++++++++++
>  src/libvirt_public.syms          |  5 +++
>  4 files changed, 99 insertions(+)
> 
> diff --git a/include/libvirt/libvirt-domain.h b/include/libvirt/libvirt-domain.h
> index 2f017c5b68..7af634cfb2 100644
> --- a/include/libvirt/libvirt-domain.h
> +++ b/include/libvirt/libvirt-domain.h
> @@ -5086,11 +5086,46 @@ int virDomainSetLifecycleAction(virDomainPtr domain,
>   */
>  # define VIR_DOMAIN_LAUNCH_SECURITY_SEV_MEASUREMENT "sev-measurement"
>  
> +/**
> + * VIR_DOMAIN_LAUNCH_SECURITY_SEV_SECRET_HEADER:
> + *
> + * A macro used to represent the SEV launch secret header. The secret header
> + * is a base64-encoded VIR_TYPED_PARAM_STRING containing artifacts needed by
> + * the SEV firmware to recover the plain text of the launch secret. See
> + * section "6.6 LAUNCH_SECRET" in the SEV API specification for a detailed
> + * description of the secret header.
> + */
> +# define VIR_DOMAIN_LAUNCH_SECURITY_SEV_SECRET_HEADER "sev-secret-header"
> +
> +/**
> + * VIR_DOMAIN_LAUNCH_SECURITY_SEV_SECRET:
> + *
> + * A macro used to represent the SEV launch secret. The secret is a
> + * base64-encoded VIR_TYPED_PARAM_STRING containing an encrypted launch
> + * secret. The secret is created by the domain owner after the SEV launch
> + * measurement is retrieved and verified.
> + */
> +# define VIR_DOMAIN_LAUNCH_SECURITY_SEV_SECRET "sev-secret"
> +
> +/**
> + * VIR_DOMAIN_LAUNCH_SECURITY_SEV_SECRET_SET_ADDRESS:
> + *
> + * A macro used to represent the physical address within the guest's memory
> + * where the secret will be set, as VIR_TYPED_PARAM_LLONG. If not specified,
> + * the address will be determined by the hypervisor.
> + */
> +# define VIR_DOMAIN_LAUNCH_SECURITY_SEV_SECRET_SET_ADDRESS "sev-secret-set-address"

Should we be using ULLONG here, since it probably doesn't make
sense for an address to be negative ?

> +
>  int virDomainGetLaunchSecurityInfo(virDomainPtr domain,
>                                     virTypedParameterPtr *params,
>                                     int *nparams,
>                                     unsigned int flags);
>  
> +int virDomainSetLaunchSecurityState(virDomainPtr domain,
> +                                    virTypedParameterPtr params,
> +                                    int nparams,
> +                                    unsigned int flags);
> +

> +/**
> + * virDomainSetLaunchSecurityState:
> + * @domain: a domain object
> + * @params: pointer to launch security parameter objects
> + * @nparams: number of launch security parameters
> + * @flags: currently used, set to 0.
> + *
> + * Set a launch security secret in the guests's memory. The secret is created
> + * by the guest owner after retrieving and verifying the launch measurement
> + * with virDomainGetLaunchSecurityInfo.
> + *
> + * See VIR_DOMAIN_LAUNCH_SECURITY_* for a detailed description of accepted
> + * launch security parameters.

Should we note something  about expected VM state/lifecycle

  When invoked, the VM must be running but with vCPUs paused.
  This can be achieved by passing VIR_DOMAIN_START_PAUSED
  to virDOmainCreate. If this method returns success, the
  vCPUs can be started with virDomainResume. On error the
  virtual machine should be destroy.
  

> + *
> + * Returns -1 in case of failure, 0 in case of success.
> + */
> +int virDomainSetLaunchSecurityState(virDomainPtr domain,
> +                                    virTypedParameterPtr params,
> +                                    int nparams,
> +                                    unsigned int flags)
> +{
> +    virConnectPtr conn = domain->conn;
> +
> +    VIR_DOMAIN_DEBUG(domain, "params=%p, nparams=%d flags=0x%x",
> +                     params, nparams, flags);
> +    VIR_TYPED_PARAMS_DEBUG(params, nparams);
> +
> +    virResetLastError();


> +
> +    virCheckDomainReturn(domain, -1);
> +    virCheckNonNullArgGoto(params, error);
> +    virCheckPositiveArgGoto(nparams, error);

Need a virCheckReadOnlyGoto too

> +    if (virTypedParameterValidateSet(conn, params, nparams) < 0)
> +        goto error;
> +
> +    if (conn->driver->domainSetLaunchSecurityState) {
> +        int ret;
> +        ret = conn->driver->domainSetLaunchSecurityState(domain, params,
> +                                                         nparams, flags);
> +        if (ret < 0)
> +            goto error;
> +        return ret;
> +    }
> +    virReportUnsupportedError();
> +
> + error:
> +    virDispatchError(domain->conn);
> +    return -1;
> +}

Regards,
Daniel
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