Re: [Qemu-devel] [PATCH v3 00/12] spapr: add support for pci hotplug

[Alexey Kardashevskiy <aik@ozlabs.ru>]

On 08/19/2014 10:21 AM, Michael Roth wrote:
> These patches are based on ppc-next, and can also be obtained from:
> 
> https://github.com/mdroth/qemu/commits/spapr-pci-hotplug-v3-ppc-next
> 
> v3:
>  * dropped emulation of firmware-managed BAR allocation. this will be
>    introduced via a follow-up series via a -machine flag and tied to
>    a separate hotplug event to avoid a race condition with guest vs.
>    "firmware"-managed BAR allocation, in conjunction with required
>    fixes to rpaphp hotplug kernel module to utilize this mode.
>  * moved drc_table into sPAPREnvironment (Alexey)
>  * moved INDICATOR_* constants and friends into spapr_pci.c (Alexey)
>  * use prefixes for global types (DrcEntry/ConfigureConnectorState) (Alexey)
>  * updated for new hotplug interface (Alexey)
>  * fixed get-power-level to report current power-level rather than
>    desired (Alexey)
>  * rebased to latest ppc-next
> 
> v2:
>   * re-ordered patches to fix build bisectability (Alexey)
>   * replaced g_warning with DPRINTF in RTAS calls for guest errors (Alexey)
>   * replaced g_warning with fprintf for qemu errors (Alexey)
>   * updated RTAS calls to use pre-existing error/success macros (Alexey)
>   * replaced DR_*/SENSOR_* macros with INDICATOR_* for set-indicator/
>     get-sensor-state (Alexey)
> 
> OVERVIEW
> 
> These patches add support for PCI hotplug for SPAPR guests. We advertise
> each PHB as DR-capable (as defined by PAPR 13.5/13.6) with 32 hotpluggable
> PCI slots per PHB, which models a standard PCI expansion device for Power
> machines where the DRC name/loc-code/index for each slot are generated
> based on bus/slot number.
> 
> This is compatible with existing guest kernel's via the rpaphp hotplug
> module, and existing userspace tools such as drmgr/librtas/rtas_errd for
> managing devices, in theory...


It would help if you described roughly what happens step-by-step when
hotplugging - when HotplugHandlerClass is called, when RTAS calls are made,
what format is used between (it is something like device tree but not
exactly), when check exception interrupt is triggered...




> 
> NOTES / ADDITIONAL DEPENDENCIES
> 
> This series relies on v1.2.19 or later of powerppc-utils (drmgr, rtas_errd,
> ppc64-diag, and librtas components, specificially), which will automate
> guest-side hotplug setup in response to an EPOW event emitted by QEMU. For
> guests with older versions of powerpc-utils, a manual workaround must be
> used (documented below).
> 
> PATCH LAYOUT
> 
> Patches
>         1-3   advertise PHBs and associated slots as hotpluggable to guests
>         4-7   add RTAS interfaces required for device configuration
>         8     fix for ppc (and other) guests that allocate IO bars starting
>               at 0x0
>         9     enables device_add/device_del for spapr machines and
>               guest-driven hotplug
>         10-12 define hotplug event structure and emit them in response to
>               device_add/device_del
> 
> USAGE
> 
> For guests with powerpc-utils 1.2.19+:
>   hotplug:
>     qemu:
>       device_add e1000,id=slot0
>   unplug:
>     qemu:
>       device_del slot0
> 
> For guests with powerpc-utils prior to 1.2.19:
>   hotplug:
>     qemu:
>       device_add e1000,id=slot0
>     guest:
>       drmgr -c pci -s "Slot 0" -n -a
>       echo 1 >/sys/bus/pci/rescan
>   unplug:
>     guest:
>       drmgr -c pci -s "Slot 0" -n -r
>       echo 1 >/sys/bus/pci/devices/0000:00:00.0/remove
>     qemu:
>       device_del slot0
> 
>  hw/pci/pci.c                |   2 +-
>  hw/ppc/spapr.c              | 172 +++++++++++++++++++++++++++++++++-
>  hw/ppc/spapr_events.c       | 224 ++++++++++++++++++++++++++++++++++++--------
>  hw/ppc/spapr_pci.c          | 689 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
>  include/hw/pci-host/spapr.h |   1 +
>  include/hw/ppc/spapr.h      |  46 ++++++++-
>  6 files changed, 1083 insertions(+), 51 deletions(-)
> 


-- 
Alexey