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[Qemu-devel] [PATCH v2 0/9] x86 CPU model versioning
From: |
Eduardo Habkost |
Subject: |
[Qemu-devel] [PATCH v2 0/9] x86 CPU model versioning |
Date: |
Thu, 27 Jun 2019 21:28:35 -0300 |
Changes v1 -> v2:
* Patch "i386: Infrastructure for versioned CPU models" was
rewritten and split in two:
* i386: Register versioned CPU models
* i386: Make unversioned CPU models be aliases
* -IBRS, -noTSX, -IBPB CPU models are now aliases
* Enable rdctl-no, ibrs-all, skip-l1dfl-vmentry in
Cascadelake-Server-v2
* New patch added:
* i386: Get model-id from CPU object on "-cpu help"
---
Original description in v1:
This series implements basic infrastructure for CPU model
versioning, as discussed before[1][2][3]. This will finally
allow us to update CPU models in ways that introduce new software
or hardware requirements.
My original plan was to use "query-cpu-model-expansion
mode=static" to resolve aliases, but I dropped that plan because
it would increase complexity for management software a lot.
static CPU models are documented as not being affected by the
machine type and accelerator at all, which would make the
versioned CPU models very inconvenient to use in the command
line. e.g.: users would be forced to replace:
-cpu Haswell
with:
-cpu
Haswell-4.1,+2apic,+monitor,+kvmclock,+kvm-nopiodelay,+kvm-asyncpf,+kvm-steal-time,+kvm-pv-eoi,+kvmclock-stable-bit,+x2apic,-acpi,-monitor,-svm
In the end, making the versioned CPU models static is not a
requirement at all: what we really need is to drop the
runnability guarantees from unversioned CPU model names, and
require management software to resolve the unversioned alias
before saving the VM configuration.
Guest ABI compatibility and live migration guarantees are going
to be kept: unversioned CPU models will still be usable with live
migration. Only runnability guarantees when updating the machine
type will be dropped. This means unversioned CPU models are
still reported as migration-safe in query-cpu-definitions.
The last patch in the series demonstrates how the new feature can
be used to update a CPU model: it adds a Cascadelake-Server-4.1.1
CPU model, including "arch-capabilities=on" and "stepping=5".
Unfortunately we can't enable arch-capabilities in the -4.1
version of Cascadelake-Server because it would break our existing
runnability guarantees.
[1] https://www.mail-archive.com/address@hidden/msg167342.html
[2] https://www.mail-archive.com/address@hidden/msg590034.html
[3] https://www.mail-archive.com/address@hidden/msg611244.html
---
Cc: Paolo Bonzini <address@hidden>
Cc: Pavel Hrdina <address@hidden>
Cc: Jiri Denemark <address@hidden>
Cc: "Hu, Robert" <address@hidden>
Cc: Tao Xu <address@hidden>
Cc: Richard Henderson <address@hidden>
Cc: "Dr. David Alan Gilbert" <address@hidden>
Cc: "Daniel P. Berrange" <address@hidden>
Cc: Igor Mammedov <address@hidden>
Eduardo Habkost (9):
qmp: Add "alias-of" field to query-cpu-definitions
i386: Add x-force-features option for testing
i386: Get model-id from CPU object on "-cpu help"
i386: Register versioned CPU models
i386: Define -IBRS, -noTSX, -IBRS versions of CPU models
i386: Replace -noTSX, -IBRS, -IBPB CPU models with aliases
i386: Make unversioned CPU models be aliases
docs: Deprecate CPU model runnability guarantees
i386: Add Cascadelake-Server-v2 CPU model
qapi/target.json | 9 +-
include/hw/i386/pc.h | 3 +
target/i386/cpu-qom.h | 10 +-
target/i386/cpu.h | 28 +
hw/i386/pc.c | 3 +
hw/i386/pc_piix.c | 4 +
hw/i386/pc_q35.c | 4 +
target/i386/cpu.c | 1028 +++++++++-----------
qemu-deprecated.texi | 19 +
tests/acceptance/x86_cpu_model_versions.py | 304 ++++++
10 files changed, 831 insertions(+), 581 deletions(-)
create mode 100644 tests/acceptance/x86_cpu_model_versions.py
--
2.18.0.rc1.1.g3f1ff2140
- [Qemu-devel] [PATCH v2 0/9] x86 CPU model versioning,
Eduardo Habkost <=
- [Qemu-devel] [PATCH v2 1/9] qmp: Add "alias-of" field to query-cpu-definitions, Eduardo Habkost, 2019/06/27
- [Qemu-devel] [PATCH v2 2/9] i386: Add x-force-features option for testing, Eduardo Habkost, 2019/06/27
- [Qemu-devel] [PATCH v2 3/9] i386: Get model-id from CPU object on "-cpu help", Eduardo Habkost, 2019/06/27
- [Qemu-devel] [PATCH v2 4/9] i386: Register versioned CPU models, Eduardo Habkost, 2019/06/27
- [Qemu-devel] [PATCH v2 5/9] i386: Define -IBRS, -noTSX, -IBRS versions of CPU models, Eduardo Habkost, 2019/06/27
- [Qemu-devel] [PATCH v2 6/9] i386: Replace -noTSX, -IBRS, -IBPB CPU models with aliases, Eduardo Habkost, 2019/06/27
- [Qemu-devel] [PATCH v2 7/9] i386: Make unversioned CPU models be aliases, Eduardo Habkost, 2019/06/27
- [Qemu-devel] [PATCH v2 8/9] docs: Deprecate CPU model runnability guarantees, Eduardo Habkost, 2019/06/27
- [Qemu-devel] [PATCH v2 9/9] i386: Add Cascadelake-Server-v2 CPU model, Eduardo Habkost, 2019/06/27
- Re: [Qemu-devel] [PATCH v2 0/9] x86 CPU model versioning, no-reply, 2019/06/27