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SubjectRe: [PATCH v4] powerpc/pseries: read the lpar name from the firmware
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Happy New Year, Michael!

Do you consider taking that patch soon?

Thanks,
Laurent.

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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