Messages in this thread | | | Subject | Re: [PATCH v5] powerpc/pseries: read the lpar name from the firmware | From | Tyrel Datwyler <> | Date | Thu, 6 Jan 2022 13:38:02 -0800 |
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On 1/6/22 8:13 AM, 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. > > However the hypervisor, like Qemu/KVM, may not support this RTAS > parameter. In that case the value reported in lparcfg is read from the > device tree and so is not updated accordingly. > > Cc: Nathan Lynch <nathanl@linux.ibm.com> > Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
My only nit would be that in general for consistency with other function names _RTAS_ and _DT_ should be lowercase. Seeing as they are statically scoped within lparcfg.c maybe its ok. Otherwise,
Reviewed-by: Tyrel Datwyler <tyreld@linux.ibm.com>
> --- > v5: > fallback to the device tree value if RTAS is not providing the value. > 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 | 93 ++++++++++++++++++++++++ > 1 file changed, 93 insertions(+) > > diff --git a/arch/powerpc/platforms/pseries/lparcfg.c b/arch/powerpc/platforms/pseries/lparcfg.c > index c7940fcfc911..8ca08fc306e7 100644 > --- a/arch/powerpc/platforms/pseries/lparcfg.c > +++ b/arch/powerpc/platforms/pseries/lparcfg.c > @@ -311,6 +311,98 @@ 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 > + > +/** > + * Read the lpar name using the RTAS ibm,get-system-parameter call. > + * > + * The name read through this call is updated if changes are made by the end > + * user on the hypervisor side. > + * > + * Some hypervisor (like Qemu) may not provide this value. In that case, a non > + * null value is returned. > + */ > +static int read_RTAS_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 -EINVAL; > + > + local_buffer = kmalloc(sizeof(*local_buffer), GFP_KERNEL); > + if (!local_buffer) > + return -ENOMEM; > + > + 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 > + rc = -ENODATA; > + > + kfree(local_buffer); > + return rc; > +} > + > +/** > + * Read the LPAR name from the Device Tree. > + * > + * The value read in the DT is not updated if the end-user is touching the LPAR > + * name on the hypervisor side. > + */ > +static int read_DT_lpar_name(struct seq_file *m) > +{ > + struct device_node *rootdn; > + const char *name; > + > + rootdn = of_find_node_by_path("/"); > + if (!rootdn) > + return -ENOENT; > + > + name = of_get_property(rootdn, "ibm,partition-name", NULL); > + if (!name) > + return -ENOENT; > + > + seq_printf(m, "partition_name=%s\n", name); > + return 0; > +} > + > +static void read_lpar_name(struct seq_file *m) > +{ > + if (read_RTAS_lpar_name(m) && read_DT_lpar_name(m)) > + pr_err_once("Error can't get the LPAR name"); > +} > + > #define SPLPAR_CHARACTERISTICS_TOKEN 20 > #define SPLPAR_MAXLENGTH 1026*(sizeof(char)) > > @@ -496,6 +588,7 @@ 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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