Re: [Qemu-devel] [PATCH v2 0/6] spapr: dedicated hotplug events and memory unplug support

[David Gibson <david@gibson.dropbear.id.au>]

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On Wed, Oct 26, 2016 at 04:59:19PM -0500, Michael Roth wrote:
> This series is based on David's ppc-for-2.8 branch, and is also available from:
> 
>   https://github.com/mdroth/qemu/commits/spapr-hotplug-event-update

Applied to ppc-for-2.8.

> 
> Changes since v1:
>   * Rebased on latest ppc-for-2.8
>   * Dropped patches relating to option vector manipulation (now merged)
>   * Moved patch introducing modern-hotplug-events option to come after
>     that actual implementation of modern-hotplug-events support. (David)
>   * Removed uneeded source name string from sPAPREventSource in favor of
>     manual lookup of the name when creating DT. (David)
>   * Don't split function return signatures across lines (David)
>   * Add comment to clarify hotplug events being enabled regardless
>     of CAS-negotiation.
>   * Avoid unecessary initialization of hotplug_ctrl in
>     spapr_lmb_release. (David)
> 
> Changes since RFC:
>   * Rebased on latest ppc-for-2.8 (with DT refactoring)
>   * Submitting as v1 now that PAPR Hotplug ACR is committed
>   * address Patchew warnings
>   * add comments to clarify spapr->ov5/ov5_cas usage. (David)
>   * revise comment to clarify intent when setting spapr->ov5
>     OV5_HP_EVT bit. (Bharata)
>   * drop internal usage of spapr_ovec_from_bitmap() in favor of
>     directly assigning bitmap to sPAPROptionVector instances. (David)
>   * standardize meaning of 'vector_len' variable through spapr_ovec_*
>     functions to be the byte-wise length of option vectors entries,
>     and not including the preceeding length byte itself. (David)
>   * fix spapr_ovec_populate_dt() to parse up to OV_MAXBITS bits
>     rather than OV_MAXBITS - 1. (David)
>   * fix spapr_ovec_populate_dt() encode the minimum of 1 option
>     vector byte instead of the max of OV_MAXBYTES in cases where
>     no option bits are set. (David)
>   * add some comments to spapr_ovec_populate_dt() to clarify what
>     is being encoded into length byte of ibm,architecture-vec-5
>   * switch 'legacy-hotplug-events' option to
>     'modern-hotplug-events' (David)
>   * modify rtas_event_log_to_source() to check for OV5_HP_EVT
>     option rather than relying on whether the hotplug source is
>     specifically enabled. Assert the latter in cases where
>     OV5_HP_EVT is set. (Bharata)
>   * drop global EventSource list in favor of an sPAPREventSource
>     list field within sPAPRMachineState (David)
>   * add CPU unplug hook in mc->unplug_request (Bharata)
> 
> 
> Patches 1-4 add support for an updated event format for hotplug events,
> which includes a new way to specify a range of DRCs/LMBs to hotplug/unplug
> using a starting position and count, which is necessary for memory unplug.
> 
> Patches 5-6 add support for memory unplug using the new event format.
> 
> In addition to kernel 4.8 or later, there are a number of patches required
> to enable support on the guest kernel side. I've including the minimum set
> of patches in my branch here:
> 
>    https://github.com/mdroth/linux/commits/spapr-hotplug-event-update
> 
>    *powerpc/pseries: advertise Hot Plug Event support to firmware
>    powerpc/pseries: Implement indexed-count hotplug memory remove
>    powerpc/pseries: Implement indexed-count hotplug memory add
> 
> Note that there is currently an issue that arises when attempting to
> offline an LMB that was onlined using a guest kernel's auto-onlining
> mechanism, which can prevent full completion of memory unplug requests.
> This is being investigated, but for the purposes of testing this can
> be worked around currently by disabling auto-onlining in guests via:
> 
>   "echo offline >/sys/devices/system/memory/auto_online_blocks"
> 
> and instead onlining the blocks manually or via udev.
> 
>  docs/specs/ppc-spapr-hotplug.txt |  55 +++++++++++++++++++++++++++------
>  hw/ppc/spapr.c                   | 178 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-----
>  hw/ppc/spapr_drc.c               |  17 +++++++++++
>  hw/ppc/spapr_events.c            | 278 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-------------------------------
>  include/hw/ppc/spapr.h           |  10 ++++--
>  include/hw/ppc/spapr_ovec.h      |   1 +
>  6 files changed, 469 insertions(+), 70 deletions(-)
> 

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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