Re: [PULL 01/53] qapi, target/i386/sev: Add cpu0-id to query-sev-capabilities

[Dov Murik]

On 19/04/2022 10:16, Dov Murik wrote:
> Thanks Paolo.
> 
> On 19/04/2022 8:50, Paolo Bonzini wrote:
>> From: Dov Murik <dovmurik@linux.ibm.com>
>>
>> Add a new field 'cpu0-id' to the response of query-sev-capabilities QMP
>> command.  The value of the field is the base64-encoded unique ID of CPU0
>> (socket 0), which can be used to retrieve the signed CEK of the CPU from
>> AMD's Key Distribution Service (KDS).
>>
>> Signed-off-by: Dov Murik <dovmurik@linux.ibm.com>
>>
>> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
>> Message-Id: <20220228093014.882288-1-dovmurik@linux.ibm.com>
>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>> ---
>>  qapi/misc-target.json |  4 ++++
>>  target/i386/sev.c     | 42 +++++++++++++++++++++++++++++++++++++++++-
>>  2 files changed, 45 insertions(+), 1 deletion(-)
>>
>> diff --git a/qapi/misc-target.json b/qapi/misc-target.json
>> index 036c5e4a91..bc9355b595 100644
>> --- a/qapi/misc-target.json
>> +++ b/qapi/misc-target.json
>> @@ -144,6 +144,8 @@
>>  #
>>  # @cert-chain:  PDH certificate chain (base64 encoded)
>>  #
>> +# @cpu0-id: Unique ID of CPU0 (base64 encoded) (since 7.0)
>> +#
> 
> Should this be changed to "since 7.1" ?
> 
> Paolo, can you modify the patch in your tree, or should I submit a new
> version?


I see the original is already merged to master, so I sent another fix-up patch:

Subject: [PATCH] qapi: Fix version of cpu0-id field
Message-ID: 20220420190129.3532623-1-dovmurik@linux.ibm.com

-Dov


> 
> -Dov
> 
>>  # @cbitpos: C-bit location in page table entry
>>  #
>>  # @reduced-phys-bits: Number of physical Address bit reduction when SEV is
>> @@ -154,6 +156,7 @@
>>  { 'struct': 'SevCapability',
>>    'data': { 'pdh': 'str',
>>              'cert-chain': 'str',
>> +            'cpu0-id': 'str',
>>              'cbitpos': 'int',
>>              'reduced-phys-bits': 'int'},
>>    'if': 'TARGET_I386' }
>> @@ -172,6 +175,7 @@
>>  #
>>  # -> { "execute": "query-sev-capabilities" }
>>  # <- { "return": { "pdh": "8CCDD8DDD", "cert-chain": "888CCCDDDEE",
>> +#                  "cpu0-id": "2lvmGwo+...61iEinw==",
>>  #                  "cbitpos": 47, "reduced-phys-bits": 5}}
>>  #
>>  ##
>> diff --git a/target/i386/sev.c b/target/i386/sev.c
>> index 025ff7a6f8..32f7dbac4e 100644
>> --- a/target/i386/sev.c
>> +++ b/target/i386/sev.c
>> @@ -531,12 +531,46 @@ e_free:
>>      return 1;
>>  }
>>  
>> +static int sev_get_cpu0_id(int fd, guchar **id, size_t *id_len, Error 
>> **errp)
>> +{
>> +    guchar *id_data;
>> +    struct sev_user_data_get_id2 get_id2 = {};
>> +    int err, r;
>> +
>> +    /* query the ID length */
>> +    r = sev_platform_ioctl(fd, SEV_GET_ID2, &get_id2, &err);
>> +    if (r < 0 && err != SEV_RET_INVALID_LEN) {
>> +        error_setg(errp, "SEV: Failed to get ID ret=%d fw_err=%d (%s)",
>> +                   r, err, fw_error_to_str(err));
>> +        return 1;
>> +    }
>> +
>> +    id_data = g_new(guchar, get_id2.length);
>> +    get_id2.address = (unsigned long)id_data;
>> +
>> +    r = sev_platform_ioctl(fd, SEV_GET_ID2, &get_id2, &err);
>> +    if (r < 0) {
>> +        error_setg(errp, "SEV: Failed to get ID ret=%d fw_err=%d (%s)",
>> +                   r, err, fw_error_to_str(err));
>> +        goto err;
>> +    }
>> +
>> +    *id = id_data;
>> +    *id_len = get_id2.length;
>> +    return 0;
>> +
>> +err:
>> +    g_free(id_data);
>> +    return 1;
>> +}
>> +
>>  static SevCapability *sev_get_capabilities(Error **errp)
>>  {
>>      SevCapability *cap = NULL;
>>      guchar *pdh_data = NULL;
>>      guchar *cert_chain_data = NULL;
>> -    size_t pdh_len = 0, cert_chain_len = 0;
>> +    guchar *cpu0_id_data = NULL;
>> +    size_t pdh_len = 0, cert_chain_len = 0, cpu0_id_len = 0;
>>      uint32_t ebx;
>>      int fd;
>>  
>> @@ -561,9 +595,14 @@ static SevCapability *sev_get_capabilities(Error **errp)
>>          goto out;
>>      }
>>  
>> +    if (sev_get_cpu0_id(fd, &cpu0_id_data, &cpu0_id_len, errp)) {
>> +        goto out;
>> +    }
>> +
>>      cap = g_new0(SevCapability, 1);
>>      cap->pdh = g_base64_encode(pdh_data, pdh_len);
>>      cap->cert_chain = g_base64_encode(cert_chain_data, cert_chain_len);
>> +    cap->cpu0_id = g_base64_encode(cpu0_id_data, cpu0_id_len);
>>  
>>      host_cpuid(0x8000001F, 0, NULL, &ebx, NULL, NULL);
>>      cap->cbitpos = ebx & 0x3f;
>> @@ -575,6 +614,7 @@ static SevCapability *sev_get_capabilities(Error **errp)
>>      cap->reduced_phys_bits = 1;
>>  
>>  out:
>> +    g_free(cpu0_id_data);
>>      g_free(pdh_data);
>>      g_free(cert_chain_data);
>>      close(fd);