Re: [PATCH 10/11] x86/sev: Extend the config-fs attestation support for an SVSM

[Tom Lendacky <thomas.lendacky@amd.com>]

On 1/26/24 19:27, Dionna Amalie Glaze wrote:
> On Fri, Jan 26, 2024 at 2:19 PM Tom Lendacky <thomas.lendacky@amd.com> wrote:
>>
>> When an SVSM is present, the guest can also request attestation reports
>> from the SVSM. These SVSM attestation reports can be used to attest the
>> SVSM and any services running within the SVSM.
>>
>> Extend the config-fs attestation support to allow for an SVSM attestation
>> report. This involves creating four (4) new config-fs attributes:
>>
>>    - 'svsm' (input)
>>      This attribute is used to determine whether the attestation request
>>      should be sent to the SVSM or to the SEV firmware.
> 
> This is where I'm torn. If there's an SVSM, it's there to provide
> paravirtualization for unenlightened guests /or/ it's there to protect

An SVSM is for enlightened guests. A para-visor would be for unenlightened
guests.

> runtime measurement registers. I don't see there being any particular
> value in bifurcating the attestation report space by adding this
> option. If there's an SVSM present, the configfs-tsm report should
> return the full SVSM attestation only.

I don't necessarily agree with that. The guest should still be able to
request a traditional attestation report.

Maybe I can remove the SVSM attribute and direct the call based on
requested VMPL level. If VMPL0 is requested, it goes through the SVSM.
If VMPL1+ is requested, it goes to the ASP.

That would mean that the privlevel_floor would need to stay at zero.

> 
>>
>>    - 'service_guid' (input)
>>      Used for requesting the attestation of a single service within the
>>      SVSM. A null GUID implies that the SVSM_ATTEST_SERVICES call should
>>      be used to request the attestation report. A non-null GUID implies
>>      that the SVSM_ATTEST_SINGLE_SERVICE call should be used.
>>
>>    - 'service_version' (input)
>>      Used with the SVSM_ATTEST_SINGLE_SERVICE call, the service version
>>      represents a specific service manifest version be used for the
>>      attestation report.
> 
> I know that this is specified for the SVSM, but I still don't know
> what the intended use case is such that we wouldn't simply always
> return the full service manifest.
> I can see an argument for an evidence requester not being ready for a
> new manifest version and wanting the older version until they can
> bridge the gap. I don't see that as needing configuration from the
> user space. We can either require new service GUIDs for new versions,
> require manifest ABIs to be internally versioned to be additive-only
> to not break verifiers that understand up to manifest byte X, or we
> allow breaking version changes through control plane configuration
> that's passed directly to the SVSM.
> 
> New versions get new GUIDs allows for gradual deprecation at the
> expense of size. I think that is a reasonable trade-off to keep from
> making tsm/report vendor-specific.

This was requested and discussed during the SVSM spec review and there
were no objections raised. See the this thread where this was discussed:

https://lore.kernel.org/linux-coco/09819cb3-1938-fe86-b948-28aaffbe584e@amd.com/

The changes you're requesting would require a new version of the spec
and updates to the protocol.

> 
>>
>>    - 'manifestblob' (output)
>>      Used to return the service manifest associated with the attestation
>>      report.
> 
> Given the above, I think we can just append the manifest to the report
> since the report size is known a priori.

We could have theoretically done the same thing with the auxblob (certs
data), but that is separate. I prefer the idea of having an individual
entry per piece of data being returned.

Thanks,
Tom

> 
>>
>> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
>> ---
>>   Documentation/ABI/testing/configfs-tsm  |  55 ++++++++++
>>   arch/x86/include/asm/sev.h              |  31 +++++-
>>   arch/x86/kernel/sev.c                   |  50 +++++++++
>>   drivers/virt/coco/sev-guest/sev-guest.c | 137 ++++++++++++++++++++++++
>>   drivers/virt/coco/tsm.c                 |  95 +++++++++++++++-
>>   include/linux/tsm.h                     |  11 ++
>>   6 files changed, 376 insertions(+), 3 deletions(-)
>>
>> diff --git a/Documentation/ABI/testing/configfs-tsm b/Documentation/ABI/testing/configfs-tsm
>> index dd24202b5ba5..c5423987d323 100644
>> --- a/Documentation/ABI/testing/configfs-tsm
>> +++ b/Documentation/ABI/testing/configfs-tsm
>> @@ -31,6 +31,21 @@ Description:
>>                  Standardization v2.03 Section 4.1.8.1 MSG_REPORT_REQ.
>>                  https://www.amd.com/content/dam/amd/en/documents/epyc-technical-docs/specifications/56421.pdf
>>
>> +What:          /sys/kernel/config/tsm/report/$name/manifestblob
>> +Date:          January, 2024
>> +KernelVersion: v6.9
>> +Contact:       linux-coco@lists.linux.dev
>> +Description:
>> +               (RO) Optional supplemental data that a TSM may emit, visibility
>> +               of this attribute depends on TSM, and may be empty if no
>> +               manifest data is available.
>> +
>> +               When @provider is "sev_guest" and the "svsm" attribute is set
>> +               this file contains the service manifest used for the SVSM
>> +               attestation report from Secure VM Service Module for SEV-SNP
>> +               Guests v1.00 Section 7.
>> +               https://www.amd.com/content/dam/amd/en/documents/epyc-technical-docs/specifications/58019.pdf
>> +
>>   What:          /sys/kernel/config/tsm/report/$name/provider
>>   Date:          September, 2023
>>   KernelVersion: v6.7
>> @@ -80,3 +95,43 @@ Contact:     linux-coco@lists.linux.dev
>>   Description:
>>                  (RO) Indicates the minimum permissible value that can be written
>>                  to @privlevel.
>> +
>> +What:          /sys/kernel/config/tsm/report/$name/svsm
>> +Date:          January, 2024
>> +KernelVersion: v6.9
>> +Contact:       linux-coco@lists.linux.dev
>> +Description:
>> +               (WO) Attribute is visible if a TSM implementation provider
>> +               supports the concept of attestation reports for TVMs running
>> +               under an SVSM, like SEV-SNP. Specifying any non-zero value
>> +               implies that the attestation report should come from the SVSM.
>> +               Secure VM Service Module for SEV-SNP Guests v1.00 Section 7.
>> +               https://www.amd.com/content/dam/amd/en/documents/epyc-technical-docs/specifications/58019.pdf
>> +
>> +What:          /sys/kernel/config/tsm/report/$name/service_guid
>> +Date:          January, 2024
>> +KernelVersion: v6.9
>> +Contact:       linux-coco@lists.linux.dev
>> +Description:
>> +               (WO) Attribute is visible if a TSM implementation provider
>> +               supports the concept of attestation reports for TVMs running
>> +               under an SVSM, like SEV-SNP. Specifying a empty or null GUID
>> +               (00000000-0000-0000-0000-000000) requests all active services
>> +               within the SVSM be part of the attestation report. Specifying
>> +               a non-null GUID requests an attestation report of just the
>> +               specified service using the manifest form specified by the
>> +               service_version attribute.
>> +               Secure VM Service Module for SEV-SNP Guests v1.00 Section 7.
>> +               https://www.amd.com/content/dam/amd/en/documents/epyc-technical-docs/specifications/58019.pdf
>> +
>> +What:          /sys/kernel/config/tsm/report/$name/service_version
>> +Date:          January, 2024
>> +KernelVersion: v6.9
>> +Contact:       linux-coco@lists.linux.dev
>> +Description:
>> +               (WO) Attribute is visible if a TSM implementation provider
>> +               supports the concept of attestation reports for TVMs running
>> +               under an SVSM, like SEV-SNP. Indicates the service manifest
>> +               version requested for the attestation report.
>> +               Secure VM Service Module for SEV-SNP Guests v1.00 Section 7.
>> +               https://www.amd.com/content/dam/amd/en/documents/epyc-technical-docs/specifications/58019.pdf
>> diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h
>> index b126e50a1358..4cafa92d1d3e 100644
>> --- a/arch/x86/include/asm/sev.h
>> +++ b/arch/x86/include/asm/sev.h
>> @@ -194,6 +194,27 @@ struct svsm_pvalidate_call {
>>          struct svsm_pvalidate_entry entry[];
>>   };
>>
>> +/*
>> + * The SVSM Attestation related structures
>> + */
>> +struct svsm_location_entry {
>> +       u64 pa;
>> +       u32 len;
>> +       u8 rsvd[4];
>> +};
>> +
>> +struct svsm_attestation_call {
>> +       struct svsm_location_entry report_buffer;
>> +       struct svsm_location_entry nonce;
>> +       struct svsm_location_entry manifest_buffer;
>> +       struct svsm_location_entry certificates_buffer;
>> +
>> +       /* For attesting a single service */
>> +       u8 service_guid[16];
>> +       u32 service_version;
>> +       u8 rsvd[4];
>> +};
>> +
>>   /*
>>    * SVSM protocol structure
>>    */
>> @@ -217,6 +238,10 @@ struct svsm_call {
>>   #define SVSM_CORE_CREATE_VCPU          2
>>   #define SVSM_CORE_DELETE_VCPU          3
>>
>> +#define SVSM_ATTEST_CALL(x)            ((1ULL << 32) | (x))
>> +#define SVSM_ATTEST_SERVICES           0
>> +#define SVSM_ATTEST_SINGLE_SERVICE     1
>> +
>>   #ifdef CONFIG_AMD_MEM_ENCRYPT
>>   extern void __sev_es_ist_enter(struct pt_regs *regs);
>>   extern void __sev_es_ist_exit(void);
>> @@ -287,6 +312,7 @@ void snp_set_wakeup_secondary_cpu(void);
>>   bool snp_init(struct boot_params *bp);
>>   void __init __noreturn snp_abort(void);
>>   int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct snp_guest_request_ioctl *rio);
>> +int snp_issue_svsm_attestation_request(u64 call_id, struct svsm_attestation_call *input);
>>   void snp_accept_memory(phys_addr_t start, phys_addr_t end);
>>   u64 snp_get_unsupported_features(u64 status);
>>   u64 sev_get_status(void);
>> @@ -316,7 +342,10 @@ static inline int snp_issue_guest_request(u64 exit_code, struct snp_req_data *in
>>   {
>>          return -ENOTTY;
>>   }
>> -
>> +static inline int snp_issue_svsm_attestation_request(u64 call_id, struct svsm_attestation_call *input)
>> +{
>> +       return -ENOTTY;
>> +}
>>   static inline void snp_accept_memory(phys_addr_t start, phys_addr_t end) { }
>>   static inline u64 snp_get_unsupported_features(u64 status) { return 0; }
>>   static inline u64 sev_get_status(void) { return 0; }
>> diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c
>> index 849df3aae4e1..83bc5efa8fcf 100644
>> --- a/arch/x86/kernel/sev.c
>> +++ b/arch/x86/kernel/sev.c
>> @@ -2378,6 +2378,56 @@ static int __init init_sev_config(char *str)
>>   }
>>   __setup("sev=", init_sev_config);
>>
>> +static void update_attestation_input(struct svsm_call *call, struct svsm_attestation_call *input)
>> +{
>> +       /* If (new) lengths have been returned, propograte them up */
>> +       if (call->rcx_out != call->rcx)
>> +               input->manifest_buffer.len = call->rcx_out;
>> +
>> +       if (call->rdx_out != call->rdx)
>> +               input->certificates_buffer.len = call->rdx_out;
>> +
>> +       if (call->r8_out != call->r8)
>> +               input->report_buffer.len = call->r8_out;
>> +}
>> +
>> +int snp_issue_svsm_attestation_request(u64 call_id, struct svsm_attestation_call *input)
>> +{
>> +       struct svsm_attestation_call *attest_call;
>> +       struct svsm_call call = {};
>> +       unsigned long flags;
>> +       u64 attest_call_pa;
>> +       int ret;
>> +
>> +       if (!vmpl)
>> +               return -EINVAL;
>> +
>> +       local_irq_save(flags);
>> +
>> +       call.caa = __svsm_get_caa();
>> +
>> +       attest_call = (struct svsm_attestation_call *)call.caa->svsm_buffer;
>> +       attest_call_pa = __svsm_get_caa_pa() + offsetof(struct svsm_ca, svsm_buffer);
>> +
>> +       memcpy(attest_call, input, sizeof(*attest_call));
>> +
>> +       /*
>> +        * Set input registers for the request and set RDX and R8 to known
>> +        * values in order to detect length values being returned in them.
>> +        */
>> +       call.rax = call_id;
>> +       call.rcx = attest_call_pa;
>> +       call.rdx = -1;
>> +       call.r8 = -1;
>> +       ret = svsm_protocol(&call);
>> +       update_attestation_input(&call, input);
>> +
>> +       local_irq_restore(flags);
>> +
>> +       return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(snp_issue_svsm_attestation_request);
>> +
>>   int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct snp_guest_request_ioctl *rio)
>>   {
>>          struct ghcb_state state;
>> diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
>> index 1ff897913bf4..3693373c4227 100644
>> --- a/drivers/virt/coco/sev-guest/sev-guest.c
>> +++ b/drivers/virt/coco/sev-guest/sev-guest.c
>> @@ -783,6 +783,140 @@ struct snp_msg_cert_entry {
>>          u32 length;
>>   };
>>
>> +static int sev_svsm_report_new(struct tsm_report *report, void *data)
>> +{
>> +       unsigned int report_len, manifest_len, certificates_len;
>> +       void *report_blob, *manifest_blob, *certificates_blob;
>> +       struct svsm_attestation_call attest_call = {};
>> +       struct tsm_desc *desc = &report->desc;
>> +       unsigned int size;
>> +       bool try_again;
>> +       void *buffer;
>> +       u64 call_id;
>> +       int ret;
>> +
>> +       /*
>> +        * Allocate pages for the request:
>> +        * - Report blob (4K)
>> +        * - Manifest blob (4K)
>> +        * - Certificate blob (16K)
>> +        *
>> +        * Above addresses must be 4K aligned
>> +        */
>> +       report_len = SZ_4K;
>> +       manifest_len = SZ_4K;
>> +       certificates_len = SEV_FW_BLOB_MAX_SIZE;
>> +
>> +retry:
>> +       size = report_len + manifest_len + certificates_len;
>> +       buffer = alloc_pages_exact(size, __GFP_ZERO);
>> +       if (!buffer)
>> +               return -ENOMEM;
>> +
>> +       report_blob = buffer;
>> +       attest_call.report_buffer.pa = __pa(report_blob);
>> +       attest_call.report_buffer.len = report_len;
>> +
>> +       manifest_blob = report_blob + report_len;
>> +       attest_call.manifest_buffer.pa = __pa(manifest_blob);
>> +       attest_call.manifest_buffer.len = manifest_len;
>> +
>> +       certificates_blob = manifest_blob + manifest_len;
>> +       attest_call.certificates_buffer.pa = __pa(certificates_blob);
>> +       attest_call.certificates_buffer.len = certificates_len;
>> +
>> +       attest_call.nonce.pa = __pa(desc->inblob);
>> +       attest_call.nonce.len = desc->inblob_len;
>> +
>> +       if (guid_is_null(&desc->service_guid)) {
>> +               call_id = SVSM_ATTEST_CALL(SVSM_ATTEST_SERVICES);
>> +       } else {
>> +               export_guid(attest_call.service_guid, &desc->service_guid);
>> +               attest_call.service_version = desc->service_version;
>> +
>> +               call_id = SVSM_ATTEST_CALL(SVSM_ATTEST_SINGLE_SERVICE);
>> +       }
>> +
>> +       ret = snp_issue_svsm_attestation_request(call_id, &attest_call);
>> +       switch (ret) {
>> +       case SVSM_SUCCESS:
>> +               break;
>> +       case SVSM_ERR_INVALID_PARAMETER:
>> +               try_again = false;
>> +
>> +               if (attest_call.report_buffer.len > report_len) {
>> +                       report_len = PAGE_ALIGN(attest_call.report_buffer.len);
>> +                       try_again = true;
>> +               }
>> +
>> +               if (attest_call.manifest_buffer.len > manifest_len) {
>> +                       manifest_len = PAGE_ALIGN(attest_call.manifest_buffer.len);
>> +                       try_again = true;
>> +               }
>> +
>> +               if (attest_call.certificates_buffer.len > certificates_len) {
>> +                       certificates_len = PAGE_ALIGN(attest_call.certificates_buffer.len);
>> +                       try_again = true;
>> +               }
>> +
>> +               /* If one of the buffers wasn't large enough, retry the request */
>> +               if (try_again) {
>> +                       free_pages_exact(buffer, size);
>> +                       goto retry;
>> +               }
>> +
>> +               ret = -EINVAL;
>> +               goto error;
>> +       case SVSM_ERR_BUSY:
>> +               ret = -EAGAIN;
>> +               goto error;
>> +       default:
>> +               pr_err_ratelimited("SVSM attestation request failed (%#x)\n", ret);
>> +               ret = -EINVAL;
>> +               goto error;
>> +       }
>> +
>> +       ret = -ENOMEM;
>> +
>> +       report_len = attest_call.report_buffer.len;
>> +       void *rbuf __free(kvfree) = kvzalloc(report_len, GFP_KERNEL);
>> +       if (!rbuf)
>> +               goto error;
>> +
>> +       memcpy(rbuf, report_blob, report_len);
>> +       report->outblob = no_free_ptr(rbuf);
>> +       report->outblob_len = report_len;
>> +
>> +       manifest_len = attest_call.manifest_buffer.len;
>> +       void *mbuf __free(kvfree) = kvzalloc(manifest_len, GFP_KERNEL);
>> +       if (!mbuf)
>> +               goto error;
>> +
>> +       memcpy(mbuf, manifest_blob, manifest_len);
>> +       report->manifestblob = no_free_ptr(mbuf);
>> +       report->manifestblob_len = manifest_len;
>> +
>> +       certificates_len = attest_call.certificates_buffer.len;
>> +       if (!certificates_len)
>> +               goto success;
>> +
>> +       void *cbuf __free(kvfree) = kvzalloc(certificates_len, GFP_KERNEL);
>> +       if (!cbuf)
>> +               goto error;
>> +
>> +       memcpy(cbuf, certificates_blob, certificates_len);
>> +       report->auxblob = no_free_ptr(cbuf);
>> +       report->auxblob_len = certificates_len;
>> +
>> +success:
>> +       ret = 0;
>> +
>> +error:
>> +       free_pages_exact(buffer, size);
>> +
>> +       return ret;
>> +}
>> +
>>   static int sev_report_new(struct tsm_report *report, void *data)
>>   {
>>          struct snp_msg_cert_entry *cert_table;
>> @@ -797,6 +931,9 @@ static int sev_report_new(struct tsm_report *report, void *data)
>>          if (desc->inblob_len != SNP_REPORT_USER_DATA_SIZE)
>>                  return -EINVAL;
>>
>> +       if (desc->svsm)
>> +               return sev_svsm_report_new(report, data);
>> +
>>          void *buf __free(kvfree) = kvzalloc(size, GFP_KERNEL);
>>          if (!buf)
>>                  return -ENOMEM;
>> diff --git a/drivers/virt/coco/tsm.c b/drivers/virt/coco/tsm.c
>> index d1c2db83a8ca..33fa26406bc6 100644
>> --- a/drivers/virt/coco/tsm.c
>> +++ b/drivers/virt/coco/tsm.c
>> @@ -35,7 +35,7 @@ static DECLARE_RWSEM(tsm_rwsem);
>>    * The attestation report format is TSM provider specific, when / if a standard
>>    * materializes that can be published instead of the vendor layout. Until then
>>    * the 'provider' attribute indicates the format of 'outblob', and optionally
>> - * 'auxblob'.
>> + * 'auxblob' and 'manifestblob'.
>>    */
>>
>>   struct tsm_report_state {
>> @@ -48,6 +48,7 @@ struct tsm_report_state {
>>   enum tsm_data_select {
>>          TSM_REPORT,
>>          TSM_CERTS,
>> +       TSM_MANIFEST,
>>   };
>>
>>   static struct tsm_report *to_tsm_report(struct config_item *cfg)
>> @@ -119,6 +120,77 @@ static ssize_t tsm_report_privlevel_floor_show(struct config_item *cfg,
>>   }
>>   CONFIGFS_ATTR_RO(tsm_report_, privlevel_floor);
>>
>> +static ssize_t tsm_report_svsm_store(struct config_item *cfg,
>> +                                    const char *buf, size_t len)
>> +{
>> +       struct tsm_report *report = to_tsm_report(cfg);
>> +       unsigned int val;
>> +       int rc;
>> +
>> +       rc = kstrtouint(buf, 0, &val);
>> +       if (rc)
>> +               return rc;
>> +
>> +       guard(rwsem_write)(&tsm_rwsem);
>> +       rc = try_advance_write_generation(report);
>> +       if (rc)
>> +               return rc;
>> +       report->desc.svsm = !!val;
>> +
>> +       return len;
>> +}
>> +CONFIGFS_ATTR_WO(tsm_report_, svsm);
>> +
>> +static ssize_t tsm_report_service_guid_store(struct config_item *cfg,
>> +                                            const char *buf, size_t len)
>> +{
>> +       struct tsm_report *report = to_tsm_report(cfg);
>> +       size_t guid_len;
>> +       int rc;
>> +
>> +       guard(rwsem_write)(&tsm_rwsem);
>> +       rc = try_advance_write_generation(report);
>> +       if (rc)
>> +               return rc;
>> +
>> +       /* Obtain the GUID string length */
>> +       guid_len = (len && buf[len - 1] == '\n') ? len - 1 : len;
>> +       if (guid_len && guid_len != UUID_STRING_LEN)
>> +               return -EINVAL;
>> +
>> +       if (guid_len == UUID_STRING_LEN) {
>> +               rc = guid_parse(buf, &report->desc.service_guid);
>> +               if (rc)
>> +                       return rc;
>> +       } else {
>> +               report->desc.service_guid = guid_null;
>> +       }
>> +
>> +       return len;
>> +}
>> +CONFIGFS_ATTR_WO(tsm_report_, service_guid);
>> +
>> +static ssize_t tsm_report_service_version_store(struct config_item *cfg,
>> +                                               const char *buf, size_t len)
>> +{
>> +       struct tsm_report *report = to_tsm_report(cfg);
>> +       unsigned int val;
>> +       int rc;
>> +
>> +       rc = kstrtouint(buf, 0, &val);
>> +       if (rc)
>> +               return rc;
>> +
>> +       guard(rwsem_write)(&tsm_rwsem);
>> +       rc = try_advance_write_generation(report);
>> +       if (rc)
>> +               return rc;
>> +       report->desc.service_version = val;
>> +
>> +       return len;
>> +}
>> +CONFIGFS_ATTR_WO(tsm_report_, service_version);
>> +
>>   static ssize_t tsm_report_inblob_write(struct config_item *cfg,
>>                                         const void *buf, size_t count)
>>   {
>> @@ -163,6 +235,9 @@ static ssize_t __read_report(struct tsm_report *report, void *buf, size_t count,
>>          if (select == TSM_REPORT) {
>>                  out = report->outblob;
>>                  len = report->outblob_len;
>> +       } else if (select == TSM_MANIFEST) {
>> +               out = report->manifestblob;
>> +               len = report->manifestblob_len;
>>          } else {
>>                  out = report->auxblob;
>>                  len = report->auxblob_len;
>> @@ -188,7 +263,7 @@ static ssize_t read_cached_report(struct tsm_report *report, void *buf,
>>
>>          /*
>>           * A given TSM backend always fills in ->outblob regardless of
>> -        * whether the report includes an auxblob or not.
>> +        * whether the report includes an auxblob/manifestblob or not.
>>           */
>>          if (!report->outblob ||
>>              state->read_generation != state->write_generation)
>> @@ -224,8 +299,10 @@ static ssize_t tsm_report_read(struct tsm_report *report, void *buf,
>>
>>          kvfree(report->outblob);
>>          kvfree(report->auxblob);
>> +       kvfree(report->manifestblob);
>>          report->outblob = NULL;
>>          report->auxblob = NULL;
>> +       report->manifestblob = NULL;
>>          rc = ops->report_new(report, provider.data);
>>          if (rc < 0)
>>                  return rc;
>> @@ -252,6 +329,15 @@ static ssize_t tsm_report_auxblob_read(struct config_item *cfg, void *buf,
>>   }
>>   CONFIGFS_BIN_ATTR_RO(tsm_report_, auxblob, NULL, TSM_OUTBLOB_MAX);
>>
>> +static ssize_t tsm_report_manifestblob_read(struct config_item *cfg, void *buf,
>> +                                           size_t count)
>> +{
>> +       struct tsm_report *report = to_tsm_report(cfg);
>> +
>> +       return tsm_report_read(report, buf, count, TSM_MANIFEST);
>> +}
>> +CONFIGFS_BIN_ATTR_RO(tsm_report_, manifestblob, NULL, TSM_OUTBLOB_MAX);
>> +
>>   #define TSM_DEFAULT_ATTRS() \
>>          &tsm_report_attr_generation, \
>>          &tsm_report_attr_provider
>> @@ -265,6 +351,9 @@ static struct configfs_attribute *tsm_report_extra_attrs[] = {
>>          TSM_DEFAULT_ATTRS(),
>>          &tsm_report_attr_privlevel,
>>          &tsm_report_attr_privlevel_floor,
>> +       &tsm_report_attr_svsm,
>> +       &tsm_report_attr_service_guid,
>> +       &tsm_report_attr_service_version,
>>          NULL,
>>   };
>>
>> @@ -280,6 +369,7 @@ static struct configfs_bin_attribute *tsm_report_bin_attrs[] = {
>>   static struct configfs_bin_attribute *tsm_report_bin_extra_attrs[] = {
>>          TSM_DEFAULT_BIN_ATTRS(),
>>          &tsm_report_attr_auxblob,
>> +       &tsm_report_attr_manifestblob,
>>          NULL,
>>   };
>>
>> @@ -288,6 +378,7 @@ static void tsm_report_item_release(struct config_item *cfg)
>>          struct tsm_report *report = to_tsm_report(cfg);
>>          struct tsm_report_state *state = to_state(report);
>>
>> +       kvfree(report->manifestblob);
>>          kvfree(report->auxblob);
>>          kvfree(report->outblob);
>>          kfree(state);
>> diff --git a/include/linux/tsm.h b/include/linux/tsm.h
>> index de8324a2223c..7c36b8448b4f 100644
>> --- a/include/linux/tsm.h
>> +++ b/include/linux/tsm.h
>> @@ -4,6 +4,7 @@
>>
>>   #include <linux/sizes.h>
>>   #include <linux/types.h>
>> +#include <linux/uuid.h>
>>
>>   #define TSM_INBLOB_MAX 64
>>   #define TSM_OUTBLOB_MAX SZ_32K
>> @@ -19,11 +20,17 @@
>>    * @privlevel: optional privilege level to associate with @outblob
>>    * @inblob_len: sizeof @inblob
>>    * @inblob: arbitrary input data
>> + * @svsm: optional indicator of where to obtain the tsm report blob
>> + * @service_guid: optional SVSM service guid to attest
>> + * @service_version: optional SVSM service manifest version requested
>>    */
>>   struct tsm_desc {
>>          unsigned int privlevel;
>>          size_t inblob_len;
>>          u8 inblob[TSM_INBLOB_MAX];
>> +       bool svsm;
>> +       guid_t service_guid;
>> +       unsigned int service_version;
>>   };
>>
>>   /**
>> @@ -33,6 +40,8 @@ struct tsm_desc {
>>    * @outblob: generated evidence to provider to the attestation agent
>>    * @auxblob_len: sizeof(@auxblob)
>>    * @auxblob: (optional) auxiliary data to the report (e.g. certificate data)
>> + * @manifestblob_len: sizeof(@manifestblob)
>> + * @manifestblob: (optional) manifest data associated with the report
>>    */
>>   struct tsm_report {
>>          struct tsm_desc desc;
>> @@ -40,6 +49,8 @@ struct tsm_report {
>>          u8 *outblob;
>>          size_t auxblob_len;
>>          u8 *auxblob;
>> +       size_t manifestblob_len;
>> +       u8 *manifestblob;
>>   };
>>
>>   /**
>> --
>> 2.42.0
>>
>>
> 
>