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SubjectRe: [PATCH v4] powerpc/pseries: read the lpar name from the firmware
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Laurent Dufour <ldufour@linux.ibm.com> writes:
> Happy New Year, Michael!
>
> Do you consider taking that patch soon?

I did but I was hoping you and Nathan could come to an agreement.

Looks like you did while I was sleeping, perfect :)

I'll pick up v5.

cheers


> On 07/12/2021, 18:11:09, Laurent Dufour wrote:
>> The LPAR name may be changed after the LPAR has been started in the HMC.
>> In that case lparstat command is not reporting the updated value because it
>> reads it from the device tree which is read at boot time.
>>
>> However this value could be read from RTAS.
>>
>> Adding this value in the /proc/powerpc/lparcfg output allows to read the
>> updated value.
>>
>> Cc: Nathan Lynch <nathanl@linux.ibm.com>
>> Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
>> ---
>> v4:
>> address Nathan's new comments limiting size of the buffer.
>> v3:
>> address Michael's comments.
>> v2:
>> address Nathan's comments.
>> change title to partition_name aligning with existing partition_id
>> ---
>> arch/powerpc/platforms/pseries/lparcfg.c | 54 ++++++++++++++++++++++++
>> 1 file changed, 54 insertions(+)
>>
>> diff --git a/arch/powerpc/platforms/pseries/lparcfg.c b/arch/powerpc/platforms/pseries/lparcfg.c
>> index f71eac74ea92..058d9a5fe545 100644
>> --- a/arch/powerpc/platforms/pseries/lparcfg.c
>> +++ b/arch/powerpc/platforms/pseries/lparcfg.c
>> @@ -311,6 +311,59 @@ static void parse_mpp_x_data(struct seq_file *m)
>> seq_printf(m, "coalesce_pool_spurr=%ld\n", mpp_x_data.pool_spurr_cycles);
>> }
>>
>> +/*
>> + * PAPR defines, in section "7.3.16 System Parameters Option", the token 55 to
>> + * read the LPAR name, and the largest output data to 4000 + 2 bytes length.
>> + */
>> +#define SPLPAR_LPAR_NAME_TOKEN 55
>> +#define GET_SYS_PARM_BUF_SIZE 4002
>> +#if GET_SYS_PARM_BUF_SIZE > RTAS_DATA_BUF_SIZE
>> +#error "GET_SYS_PARM_BUF_SIZE is larger than RTAS_DATA_BUF_SIZE"
>> +#endif
>> +static void read_lpar_name(struct seq_file *m)
>> +{
>> + int rc, len, token;
>> + union {
>> + char raw_buffer[GET_SYS_PARM_BUF_SIZE];
>> + struct {
>> + __be16 len;
>> + char name[GET_SYS_PARM_BUF_SIZE-2];
>> + };
>> + } *local_buffer;
>> +
>> + token = rtas_token("ibm,get-system-parameter");
>> + if (token == RTAS_UNKNOWN_SERVICE)
>> + return;
>> +
>> + local_buffer = kmalloc(sizeof(*local_buffer), GFP_KERNEL);
>> + if (!local_buffer)
>> + return;
>> +
>> + do {
>> + spin_lock(&rtas_data_buf_lock);
>> + memset(rtas_data_buf, 0, sizeof(*local_buffer));
>> + rc = rtas_call(token, 3, 1, NULL, SPLPAR_LPAR_NAME_TOKEN,
>> + __pa(rtas_data_buf), sizeof(*local_buffer));
>> + if (!rc)
>> + memcpy(local_buffer->raw_buffer, rtas_data_buf,
>> + sizeof(local_buffer->raw_buffer));
>> + spin_unlock(&rtas_data_buf_lock);
>> + } while (rtas_busy_delay(rc));
>> +
>> + if (!rc) {
>> + /* Force end of string */
>> + len = min((int) be16_to_cpu(local_buffer->len),
>> + (int) sizeof(local_buffer->name)-1);
>> + local_buffer->name[len] = '\0';
>> +
>> + seq_printf(m, "partition_name=%s\n", local_buffer->name);
>> + } else
>> + pr_err_once("Error calling get-system-parameter (0x%x)\n", rc);
>> +
>> + kfree(local_buffer);
>> +}
>> +
>> +
>> #define SPLPAR_CHARACTERISTICS_TOKEN 20
>> #define SPLPAR_MAXLENGTH 1026*(sizeof(char))
>>
>> @@ -496,6 +549,7 @@ static int pseries_lparcfg_data(struct seq_file *m, void *v)
>>
>> if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
>> /* this call handles the ibm,get-system-parameter contents */
>> + read_lpar_name(m);
>> parse_system_parameter_string(m);
>> parse_ppp_data(m);
>> parse_mpp_data(m);

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