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Re: [Qemu-ppc] [PATCHv3 0/4] Clean up compatibility mode handling
From: |
Greg Kurz |
Subject: |
Re: [Qemu-ppc] [PATCHv3 0/4] Clean up compatibility mode handling |
Date: |
Fri, 28 Apr 2017 11:29:22 +0200 |
On Thu, 27 Apr 2017 17:28:39 +1000
David Gibson <address@hidden> wrote:
> This is a rebased and revised version of my patches revising CPU
> compatiblity mode handling on ppc, last posted in November. Since
> then, many of the patches have already been merged (some for 2.9, some
> since). This is what's left.
>
> * There was conceptual confusion about what a compatibility mode
> means, and how it interacts with the machine type. This cleans
> that up, clarifying that a compatibility mode (as an externally set
> option) only makes sense on machine types that don't permit the
> guest hypervisor privilege (i.e. 'pseries')
>
> * It was previously the user's (or management layer's) responsibility
> to determine compatibility of CPUs on either end for migration.
> This uses the compatibility modes to check that properly during an
> incoming migration.
>
> This hasn't been extensively tested yet. There are quite a few
> migration cases to consider, for example:
>
Hi David,
I'll rerun the tests shortly.
Cheers,
--
Greg
> Basic:
>
> 1) Boot guest with -cpu host
> Should go into POWER8 compat mode after CAS
> Previously would have been raw mode
>
> 2) Boot guest with -machine pseries,max-cpu-compat=power7 -cpu host
> Should go into POWER7 compat mode
>
> 3) Boot guest with -cpu host,compat=power7
> Should act as (2), but print a warning
>
> 4) Boot guest via libvirt with power7 compat mode specified in XML
> Should act as (3), (2) once we fix libvirt
>
> 5) Hack guest to only advertise power7 compatibility, boot with -cpu host
> Should go into POWER7 compat mode after CAS
>
> 6) Hack guest to only advertise real PVRs
> Should remain in POWER8 raw mode after CAS
>
> 7) Hack guest to only advertise real PVRs
> Boot with -machine pseries,max-cpu-compat=power8
> Should fail at CAS time
>
> 8) Hack guest to only advertise power7 compatibility, boot with -cpu host
> Reboot to normal guest
> Should go to power7 compat mode after CAS of boot 1
> Should revert to raw mode on reboot
> SHould go to power8 compat mode after CAS of boot 2
>
> Migration:
>
> 9) Boot guest with qemu-2.6 -machine pseries-2.6 -cpu host
> Migrate to qemu-2.8 -machine pseries-2.6 -cpu host
> Should work, end up running in power8 raw mode
>
> 10) Boot guest with qemu-2.7 -machine pseries-2.7 -cpu host
> Migrate to qemu-2.8 -machine pseries-2.7 -cpu host
> Should work, end up running in power8 raw mode
>
> 11) Boot guest with qemu-2.7 -machine pseries-2.7 -cpu host,compat=power7
> Migrate to qemu-2.8 -machine pseries-2.7 -cpu host,compat=power7
> Should work, be running in POWER7 compat after, but give warning like
> (3)
>
> 12) Boot guest with qemu-2.7 -machine pseries-2.7 -cpu host,compat=power7
> Migrate to qemu-2.8 -machine pseries-2.7,max-cpu-compat=power7 -cpu host
> Should work, be running in POWER7 compat after, no warning
>
> 13) Boot to SLOF with qemu-2.6 -machine pseries-2.6 -cpu host
> Migrate to qemu-2.8 -machine pseries-2.6 -cpu host
>
> ?
>
> 14) Boot to SLOF with qemu-2.7 -machine pseries-2.7 -cpu host
> Migrate to qemu-2.8 -machine pseries-2.7 -cpu host
> ?
>
> 15) Boot to SLOF with qemu-2.7 -machine pseries-2.7 -cpu host,compat=power7
> Migrate to qemu-2.8 -machine pseries-2.7 -cpu host,compat=power7
> ?
>
> 16) Boot to SLOF with qemu-2.7 -machine pseries-2.7 -cpu host,compat=power7
> Migrate to qemu-2.8 -machine pseries-2.7,max-cpu-compat=power7 -cpu host
> ?
>
> 17) Boot guest with qemu-2.6 -machine pseries-2.6 -cpu host
> Migrate to qemu-2.7.z -machine pseries-2.6 -cpu host
> Should work
>
> 18) Hack guest to only advertise power7 compatibility, boot with -cpu host
> Boot with qemu-2.8, migrate to qemu-2.8
> Should be in power7 compat mode after CAS on source, and still
> in power7 compat mode on destination
>
>
> Changes since RFCv2:
> * Many patches dropped, since they're already merged
> * Rebased, fixed conflicts
> * Restored support for backwards migration (wasn't as complicated as
> I thought)
> * Updated final patch's description to more accurately reflect the
> logic
>
> Changes since RFCv1:
> * Change CAS logic to prefer compatibility modes over raw mode
> * Simplified by giving up on half-hearted attempts to maintain
> backwards migration
> * Folded migration stream changes into a single patch
> * Removed some preliminary patches which are already merged
>
>
>
> David Gibson (3):
> pseries: Move CPU compatibility property to machine
> pseries: Reset CPU compatibility mode
> ppc: Rework CPU compatibility testing across migration
>
> Greg Kurz (1):
> qapi: add explicit null to string input and output visitors
>
> hw/ppc/spapr.c | 8 ++++-
> hw/ppc/spapr_cpu_core.c | 47 +++++++++++++++++++------
> hw/ppc/spapr_hcall.c | 2 +-
> include/hw/ppc/spapr.h | 12 ++++---
> qapi/string-input-visitor.c | 11 ++++++
> qapi/string-output-visitor.c | 14 ++++++++
> target/ppc/compat.c | 65 ++++++++++++++++++++++++++++++++++
> target/ppc/cpu.h | 6 ++--
> target/ppc/machine.c | 71 +++++++++++++++++++++++++++++++++++--
> target/ppc/translate_init.c | 84
> ++++++++++++--------------------------------
> 10 files changed, 238 insertions(+), 82 deletions(-)
>
pgphZ9z2pH0TL.pgp
Description: OpenPGP digital signature
- [Qemu-ppc] [PATCHv3 0/4] Clean up compatibility mode handling, David Gibson, 2017/04/27
- [Qemu-ppc] [PATCHv3 1/4] qapi: add explicit null to string input and output visitors, David Gibson, 2017/04/27
- [Qemu-ppc] [PATCHv3 4/4] ppc: Rework CPU compatibility testing across migration, David Gibson, 2017/04/27
- [Qemu-ppc] [PATCHv3 3/4] pseries: Reset CPU compatibility mode, David Gibson, 2017/04/27
- [Qemu-ppc] [PATCHv3 2/4] pseries: Move CPU compatibility property to machine, David Gibson, 2017/04/27
- Re: [Qemu-ppc] [Qemu-devel] [PATCHv3 0/4] Clean up compatibility mode handling, no-reply, 2017/04/27
- Re: [Qemu-ppc] [PATCHv3 0/4] Clean up compatibility mode handling,
Greg Kurz <=