Messages in this thread | | | Date | Thu, 6 Jan 2022 10:17:48 +0100 | Subject | Re: [PATCH v4] powerpc/pseries: read the lpar name from the firmware | From | Laurent Dufour <> |
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On 06/01/2022, 02:17:21, Tyrel Datwyler wrote: > On 1/5/22 3:19 PM, Nathan Lynch wrote: >> Laurent Dufour <ldufour@linux.ibm.com> writes: >>> 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. >>> >>> Do you consider taking that patch soon? >> >> This version prints an error on non-PowerVM guests the first time >> lparcfg is read. > > I assume because QEMU doesn't implement the LPAR_NAME token for get_sysparm. > >> >> And I still contend that having this function fall back to reporting the >> partition name in the DT would provide a beneficial consistency in the >> user-facing API, allowing programs to avoid hypervisor-specific branches >> in their code. > > Agreed, if the get_sysparm fails just report the lpar-name from the device tree.
My aim is to not do in the kernel what can be easily done in user space but avoiding user space program hypervisor-specific branches is a good point.
Note that if the RTAS call has been available to unprivileged user, all that stuff would have been made in user space, so hypervisor-specific...
Anyway, I'll work on a new version fetching the DT value in the case the RTAS call is failing.
Thanks, Laurent.
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