Re: [Qemu-ppc] [PATCHv2 0/8] spapr: DRC cleanups (part VI)

[Daniel Henrique Barboza]

On 07/12/2017 09:57 PM, David Gibson wrote:
> On Wed, Jul 12, 2017 at 10:48:38AM -0300, Daniel Henrique Barboza wrote:
> > The dreaded Libvirt hotplug-migrate-hotunplug scenario is working nicely.
> Good to hear.
>
> > device_add when the machine is in RUN_STATE_PRELAUNCH (-S) still doesn't
> > work but it is expected - as discussed in "[RFC drcVI PATCH] spapr: reset
> > DRCs
> > on migration pre_load​", this scenario can't be fixed solely by this DRC
> > cleanup.
> Hmm.. what's the exact test case you're using here?  The prelaunch
> case I tried _did_ work (queueing the event during prelaunch, then
> completing the hotplug sequence once the guest had booted).

This is the test case:

sudo ./qemu-system-ppc64 -name migrate_qemu -boot strict=on --enable-kvm 
-device nec-usb-xhci,id=usb,bus=pci.0,addr=0xf -device 
spapr-vscsi,id=scsi0,reg=0x2000 -smp 
1,maxcpus=4,sockets=4,cores=1,threads=1 --machine 
pseries,accel=kvm,usb=off,dump-guest-core=off -m 4G,slots=32,maxmem=32G 
-drive 
file=/home/danielhb/vm_imgs/ubuntu1704.qcow2,format=qcow2,if=none,id=drive-virtio-disk0,cache=none 
-device 
virtio-blk-pci,scsi=off,bus=pci.0,addr=0x2,drive=drive-virtio-disk0,id=virtio-disk0,bootindex=1 
-nographic -S
QEMU 2.9.50 monitor - type 'help' for more information
(qemu)
(qemu) device_add host-spapr-cpu-core,id=core1,core-id=1
(qemu) cont

(...)

After OS boots:

address@hidden:~$ lscpu
Architecture:          ppc64le
Byte Order:            Little Endian
CPU(s):                1
On-line CPU(s) list:   0
Thread(s) per core:    1
Core(s) per socket:    1
Socket(s):             1
NUMA node(s):          1
Model:                 2.1 (pvr 004b 0201)
Model name:            POWER8E (raw), altivec supported
Hypervisor vendor:     horizontal
Virtualization type:   full
L1d cache:             64K
L1i cache:             32K
NUMA node0 CPU(s):     0
address@hidden:~$ (qemu)
(qemu) info cpus
* CPU #0: nip=0xc0000000000a3e0c thread_id=6134
  CPU #1: nip=0x0000000000000000 (halted) thread_id=6163
(qemu) info hotpluggable-cpus
Hotpluggable CPUs:
  type: "host-spapr-cpu-core"
  vcpus_count: "1"
  CPUInstance Properties:
    core-id: "3"
  type: "host-spapr-cpu-core"
  vcpus_count: "1"
  CPUInstance Properties:
    core-id: "2"
  type: "host-spapr-cpu-core"
  vcpus_count: "1"
  qom_path: "/machine/peripheral/core1"
  CPUInstance Properties:
    core-id: "1"
  type: "host-spapr-cpu-core"
  vcpus_count: "1"
  qom_path: "/machine/unattached/device[0]"
  CPUInstance Properties:
    core-id: "0"
(qemu)


I am not aware of anyone (e.g. Libvirt) using device_add at that point 
so it's not
urgent to make this work AFAIC. I was just curious of why it doesn't.


Daniel



> > Given that we'll review the DT code sometime in the future I guess we can
> > postpone the fix for device_adding in pre-launch for that time.
> >
> >
> > Tested-by: Daniel Barboza <address@hidden>
> >
> > On 07/12/2017 02:53 AM, David Gibson wrote:
> > > This sixth set of DRC cleanup patches is a complete rework of DRC
> > > state management.  We stop tracking some unnecessary things, and
> > > change the basic state representation to a simpler and more robust
> > > model.
> > >
> > > Many of the patches in this set "break" migration from earlier git
> > > snapshots, but not from any released qemu version.  The previous
> > > migration stream format had multiple problems, so better to fix them
> > > now, before 2.10 is out.
> > >
> > > Although there are certainly more things that can be improved in the
> > > DRC system, with this series we should have a solid foundation for
> > > migrating DRCs - the state trasferred is about as minimal and well
> > > defined as it's possible to be.
> > >
> > > Changes since v1:
> > >     * Rebased onto current tree
> > >     * Added cleanup to unplug path
> > >     * Added restriction of DR-indicator to physical DRCs
> > >     * Included revised version of Laurent's patch to correctly handle
> > >       things "hot" plugged before incoming migration
> > >
> > > David Gibson (7):
> > >     spapr: Remove 'awaiting_allocation' DRC flag
> > >     spapr: Simplify unplug path
> > >     spapr: Refactor spapr_drc_detach()
> > >     spapr: Cleanups relating to DRC awaiting_release field
> > >     spapr: Consolidate DRC state variables
> > >     spapr: Remove sPAPRConfigureConnectorState sub-structure
> > >     spapr: Implement DR-indicator for physical DRCs only
> > >
> > > Laurent Vivier (1):
> > >     spapr: Treat devices added before inbound migration as coldplugged
> > >
> > >    hw/ppc/spapr.c             |  89 +++-------
> > >    hw/ppc/spapr_drc.c         | 399 
> > > ++++++++++++++++++++++++---------------------
> > >    hw/ppc/spapr_pci.c         |  17 +-
> > >    hw/ppc/trace-events        |   3 +-
> > >    include/hw/ppc/spapr_drc.h |  74 ++++++---
> > >    5 files changed, 301 insertions(+), 281 deletions(-)