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[Qemu-devel] [PULL v4 39/43] docs: Deprecate CPU model runnability guara
From: |
Eduardo Habkost |
Subject: |
[Qemu-devel] [PULL v4 39/43] docs: Deprecate CPU model runnability guarantees |
Date: |
Wed, 3 Jul 2019 15:07:22 -0300 |
Document that CPU model runnability guarantees won't apply to
unversioned CPU models anymore.
Signed-off-by: Eduardo Habkost <address@hidden>
Message-Id: <address@hidden>
Reviewed-by: Daniel P. Berrangé <address@hidden>
Signed-off-by: Eduardo Habkost <address@hidden>
---
qemu-deprecated.texi | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/qemu-deprecated.texi b/qemu-deprecated.texi
index 9cba82d5ec..18f85f70e1 100644
--- a/qemu-deprecated.texi
+++ b/qemu-deprecated.texi
@@ -276,3 +276,22 @@ Note that if you are exposing the export via /dev/nbd0, it
is easier
to just export the entire image and then mount only /dev/nbd0p1 than
it is to reinvoke @command{qemu-nbd -c /dev/nbd0} limited to just a
subset of the image.
+
+@section Backwards compatibility
+
+@subsection Runnability guarantee of CPU models (since 4.1.0)
+
+Previous versions of QEMU never changed existing CPU models in
+ways that introduced additional host software or hardware
+requirements to the VM. This allowed management software to
+safely change the machine type of an existing VM without
+introducing new requirements ("runnability guarantee"). This
+prevented CPU models from being updated to include CPU
+vulnerability mitigations, leaving guests vulnerable in the
+default configuration.
+
+The CPU model runnability guarantee won't apply anymore to
+existing CPU models. Management software that needs runnability
+guarantees must resolve the CPU model aliases using te
+``alias-of'' field returned by the ``query-cpu-definitions'' QMP
+command.
--
2.18.0.rc1.1.g3f1ff2140
- [Qemu-devel] [PULL v4 26/43] i386: Remove unused host_cpudef variable, (continued)
- [Qemu-devel] [PULL v4 26/43] i386: Remove unused host_cpudef variable, Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 27/43] target/i386: Add CPUID.1F generation support for multi-dies PCMachine, Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 29/43] vl.c: Add -smp, dies=* command line support and update doc, Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 28/43] machine: Refactor smp_parse() in vl.c as MachineClass::smp_parse(), Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 33/43] i386: Add x-force-features option for testing, Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 30/43] qmp: Add deprecation information to query-machines, Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 35/43] i386: Register versioned CPU models, Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 36/43] i386: Define -IBRS, -noTSX, -IBRS versions of CPU models, Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 37/43] i386: Replace -noTSX, -IBRS, -IBPB CPU models with aliases, Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 38/43] i386: Make unversioned CPU models be aliases, Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 39/43] docs: Deprecate CPU model runnability guarantees,
Eduardo Habkost <=
- [Qemu-devel] [PULL v4 40/43] i386: Add Cascadelake-Server-v2 CPU model, Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 41/43] numa: Make deprecation warnings conditional on !qtest_enabled(), Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 42/43] numa: allow memory-less nodes when using memdev as backend, Eduardo Habkost, 2019/07/03
- [Qemu-devel] [PULL v4 43/43] tests: use -numa memdev option in tests instead of legacy 'mem' option, Eduardo Habkost, 2019/07/03
- Re: [Qemu-devel] [PULL v4 00/43] Machine and x86 queue, 2019-07-03, Eduardo Habkost, 2019/07/03