Re: [PATCH v5 07/29] s390x/diag: Implement DIAG 320 subcode 1

[Zhuoying Cai <zycai@linux.ibm.com>]

On 8/26/25 6:30 PM, Jared Rossi wrote:
> 
> 
> On 8/18/25 5:43 PM, Zhuoying Cai wrote:
>> DIAG 320 subcode 1 provides information needed to determine
>> the amount of storage to store one or more certificates from the
>> certificate store.
>>
>> Upon successful completion, this subcode returns information of the current
>> cert store, such as the number of certificates stored and allowed in the cert
>> store, amount of space may need to be allocate to store a certificate,
>> etc for verification-certificate blocks (VCBs).
>>
>> The subcode value is denoted by setting the left-most bit
>> of an 8-byte field.
>>
>> The verification-certificate-storage-size block (VCSSB) contains
>> the output data when the operation completes successfully. A VCSSB
>> length of 4 indicates that no certificate are available in the cert
>> store.
>>
>> Signed-off-by: Zhuoying Cai <zycai@linux.ibm.com>
>> ---
>>   docs/specs/s390x-secure-ipl.rst | 10 ++++++
>>   include/hw/s390x/ipl/diag320.h  | 22 +++++++++++++
>>   target/s390x/diag.c             | 56 ++++++++++++++++++++++++++++++++-
>>   3 files changed, 87 insertions(+), 1 deletion(-)
>>
>> diff --git a/docs/specs/s390x-secure-ipl.rst b/docs/specs/s390x-secure-ipl.rst
>> index 70e9a66fe0..ddc15f0322 100644
>> --- a/docs/specs/s390x-secure-ipl.rst
>> +++ b/docs/specs/s390x-secure-ipl.rst
>> @@ -23,3 +23,13 @@ Subcode 0 - query installed subcodes
>>       Returns a 256-bit installed subcodes mask (ISM) stored in the installed
>>       subcodes block (ISB). This mask indicates which sucodes are currently
>>       installed and available for use.
>> +
>> +Subcode 1 - query verification certificate storage information
>> +    Provides the information required to determine the amount of memory needed to
>> +    store one or more verification-certificates (VCs) from the certificate store (CS).
>> +
>> +    Upon successful completion, this subcode returns various storage size values for
>> +    verification-certificate blocks (VCBs).
>> +
>> +    The output is returned in the verification-certificate-storage-size block (VCSSB).
>> +    A VCSSB length of 4 indicates that no certificates are available in the CS.
>> diff --git a/include/hw/s390x/ipl/diag320.h b/include/hw/s390x/ipl/diag320.h
>> index aa04b699c6..6e4779c699 100644
>> --- a/include/hw/s390x/ipl/diag320.h
>> +++ b/include/hw/s390x/ipl/diag320.h
>> @@ -11,10 +11,32 @@
>>   #define S390X_DIAG320_H
>>   
>>   #define DIAG_320_SUBC_QUERY_ISM     0
>> +#define DIAG_320_SUBC_QUERY_VCSI    1
>>   
>>   #define DIAG_320_RC_OK              0x0001
>>   #define DIAG_320_RC_NOT_SUPPORTED   0x0102
>> +#define DIAG_320_RC_INVAL_VCSSB_LEN 0x0202
>>   
>>   #define DIAG_320_ISM_QUERY_SUBCODES 0x80000000
>> +#define DIAG_320_ISM_QUERY_VCSI     0x40000000
>> +
>> +#define VCSSB_NO_VC     4
>> +#define VCSSB_MIN_LEN   128
>> +#define VCE_HEADER_LEN  128
>> +#define VCB_HEADER_LEN  64
>> +
>> +struct VCStorageSizeBlock {
>> +    uint32_t length;
>> +    uint8_t reserved0[3];
>> +    uint8_t version;
>> +    uint32_t reserved1[6];
>> +    uint16_t total_vc_ct;
>> +    uint16_t max_vc_ct;
>> +    uint32_t reserved3[11];
>> +    uint32_t max_single_vcb_len;
>> +    uint32_t total_vcb_len;
>> +    uint32_t reserved4[10];
>> +};
>> +typedef struct VCStorageSizeBlock VCStorageSizeBlock;
> Previous versions included a build bug message for the size of this 
> structure,
> was it dropped by mistake?
> 

Thanks for pointing it out. The use of the build error message was
misunderstood as unnecessary in the last version.

I'll add it back in the next version.

>>   
>>   #endif
>> diff --git a/target/s390x/diag.c b/target/s390x/diag.c
>> index e67ee57f01..b42cf8fe98 100644
>> --- a/target/s390x/diag.c
>> +++ b/target/s390x/diag.c
>> @@ -191,11 +191,47 @@ out:
>>       }
>>   }
>>   
>> +static int handle_diag320_query_vcsi(S390CPU *cpu, uint64_t addr, uint64_t r1,
>> +                                     uintptr_t ra, S390IPLCertificateStore *qcs)
>> +{
>> +    g_autofree VCStorageSizeBlock *vcssb = NULL;
>> +
>> +    vcssb = g_new0(VCStorageSizeBlock, 1);
>> +    if (s390_cpu_virt_mem_read(cpu, addr, r1, vcssb, sizeof(*vcssb))) {
>> +        s390_cpu_virt_mem_handle_exc(cpu, ra);
>> +        return -1;
>> +    }
>> +
>> +    if (be32_to_cpu(vcssb->length) < VCSSB_MIN_LEN) {
>> +        return DIAG_320_RC_INVAL_VCSSB_LEN;
>> +    }
>> +
>> +    if (!qcs->count) {
>> +        vcssb->length = cpu_to_be32(VCSSB_NO_VC);
>> +    } else {
>> +        vcssb->version = 0;
>> +        vcssb->total_vc_ct = cpu_to_be16(qcs->count);
>> +        vcssb->max_vc_ct = cpu_to_be16(MAX_CERTIFICATES);
>> +        vcssb->max_single_vcb_len = cpu_to_be32(VCB_HEADER_LEN + VCE_HEADER_LEN +
>> +                                                qcs->max_cert_size);
>> +        vcssb->total_vcb_len = cpu_to_be32(VCB_HEADER_LEN + qcs->count * VCE_HEADER_LEN +
>> +                                           qcs->total_bytes);
>> +    }
>> +
>> +    if (s390_cpu_virt_mem_write(cpu, addr, r1, vcssb, be32_to_cpu(vcssb->length))) {
>> +        s390_cpu_virt_mem_handle_exc(cpu, ra);
>> +        return -1;
>> +    }
>> +    return DIAG_320_RC_OK;
>> +}
>> +
>>   void handle_diag_320(CPUS390XState *env, uint64_t r1, uint64_t r3, uintptr_t ra)
>>   {
>>       S390CPU *cpu = env_archcpu(env);
>> +    S390IPLCertificateStore *qcs = s390_ipl_get_certificate_store();
>>       uint64_t subcode = env->regs[r3];
>>       uint64_t addr = env->regs[r1];
>> +    int rc;
>>   
>>       if (env->psw.mask & PSW_MASK_PSTATE) {
>>           s390_program_interrupt(env, PGM_PRIVILEGED, ra);
>> @@ -219,7 +255,8 @@ void handle_diag_320(CPUS390XState *env, uint64_t r1, uint64_t r3, uintptr_t ra)
>>            * but the current set of subcodes can fit within a single word
>>            * for now.
>>            */
>> -        uint32_t ism_word0 = cpu_to_be32(DIAG_320_ISM_QUERY_SUBCODES);
>> +        uint32_t ism_word0 = cpu_to_be32(DIAG_320_ISM_QUERY_SUBCODES |
>> +                                         DIAG_320_ISM_QUERY_VCSI);
>>   
>>           if (s390_cpu_virt_mem_write(cpu, addr, r1, &ism_word0, sizeof(ism_word0))) {
>>               s390_cpu_virt_mem_handle_exc(cpu, ra);
>> @@ -228,6 +265,23 @@ void handle_diag_320(CPUS390XState *env, uint64_t r1, uint64_t r3, uintptr_t ra)
>>   
>>           env->regs[r1 + 1] = DIAG_320_RC_OK;
>>           break;
>> +    case DIAG_320_SUBC_QUERY_VCSI:
>> +        if (!diag_parm_addr_valid(addr, sizeof(VCStorageSizeBlock), true)) {
>> +            s390_program_interrupt(env, PGM_ADDRESSING, ra);
>> +            return;
>> +        }
>> +
>> +        if (addr & 0x7) {
>> +            s390_program_interrupt(env, PGM_ADDRESSING, ra);
>> +            return;
>> +        }
>> +
>> +        rc = handle_diag320_query_vcsi(cpu, addr, r1, ra, qcs);
>> +        if (rc == -1) {
>> +            return;
>> +        }
>> +        env->regs[r1 + 1] = rc;
>> +        break;
>>       default:
>>           env->regs[r1 + 1] = DIAG_320_RC_NOT_SUPPORTED;
>>           break;
> Regards,
> Jared rossi