Re: [PATCH v2 1/3] qapi/machine-target: refactor machine-target
First of all, my sincere apologies for the delayed review. The patch series needs a rebase. But let me review it first. Dinah Baum writes: > Moved architecture agnostic data types to their own > file to avoid "attempt to use poisoned TARGET_*" > error that results when including qapi header > with commands that aren't defined for all architectures. > Required to implement enabling `query-cpu-model-expansion` > on all architectures > > Signed-off-by: Dinah Baum > Reviewed-by: Philippe Mathieu-Daudé > --- > MAINTAINERS | 1 + > qapi/machine-target-common.json | 79 + > qapi/machine-target.json| 73 +- > qapi/meson.build| 1 + > 4 files changed, 82 insertions(+), 72 deletions(-) > create mode 100644 qapi/machine-target-common.json Do we really want to create qapi/machine-target-common.json? Before we can answer this, I think I should explain how we use QAPI modules so far. You already know about target-independent vs. target-dependent code. In target-dependent code, a multitude of additional macros are available, such as TARGET_S390X, TARGET_I386, TARGET_ARM, ... We poison them to prevent accidental use in target-independent code. Since target-dependent code needs to be compiled per target, we try to keep as much code as we can target-independent. QAPI-generated code is target-independent except for code generated for QAPI modules whose name ends with "-target". Yes, that's a bit of a hack. See qapi/meson.build. When a subsystem needs QAPI schema stuff, we generally put it into its own module. For instance, the PCI subsystem's QAPI schema is in the pci module (qapi/pci.json). See MAINTAINERS for more. Most subsystems' QAPI schema is entirely target-independent. If a subsystem needs some target-dependence in its schema, we split the QAPI module into a target-dependent and a target-independent part. We have two such pairs: misc and misc-target, machine and machine-target. Can we stick to this convention? I.e. move to existing machine.json instead to new machine-target-common.json. Let's have a closer look. This patch moves a few types from (machine-dependent) machine-target.json to new (and machine-independent) machine-target-common.json. The next patch moves another type and a command after removing their machine-dependence. After both moves, machine-target.json needs to include machine-target-common.json for CpuModelInfo and CpuModelCompareResult. Aside: the latter is only ever used in machine-target.json. We could keep it there. If we move to machine.json instead, then machine-target.json needs to include that. Would that work? If not: I think the name machine-target-common.json is unfortunate, because it kind of suggests machine-dependence. [...]
[PATCH v2 1/3] qapi/machine-target: refactor machine-target
Moved architecture agnostic data types to their own
file to avoid "attempt to use poisoned TARGET_*"
error that results when including qapi header
with commands that aren't defined for all architectures.
Required to implement enabling `query-cpu-model-expansion`
on all architectures
Signed-off-by: Dinah Baum
Reviewed-by: Philippe Mathieu-Daudé
---
MAINTAINERS | 1 +
qapi/machine-target-common.json | 79 +
qapi/machine-target.json| 73 +-
qapi/meson.build| 1 +
4 files changed, 82 insertions(+), 72 deletions(-)
create mode 100644 qapi/machine-target-common.json
diff --git a/MAINTAINERS b/MAINTAINERS
index ef45b5e71e..fbc4d7be66 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1751,6 +1751,7 @@ F: hw/core/numa.c
F: hw/cpu/cluster.c
F: qapi/machine.json
F: qapi/machine-target.json
+F: qapi/machine-target-common.json
F: include/hw/boards.h
F: include/hw/core/cpu.h
F: include/hw/cpu/cluster.h
diff --git a/qapi/machine-target-common.json b/qapi/machine-target-common.json
new file mode 100644
index 00..1e6da3177d
--- /dev/null
+++ b/qapi/machine-target-common.json
@@ -0,0 +1,79 @@
+# -*- Mode: Python -*-
+# vim: filetype=python
+
+##
+# = Common data types for machine target commands
+##
+
+##
+# @CpuModelInfo:
+#
+# Virtual CPU model.
+#
+# A CPU model consists of the name of a CPU definition, to which
+# delta changes are applied (e.g. features added/removed). Most magic values
+# that an architecture might require should be hidden behind the name.
+# However, if required, architectures can expose relevant properties.
+#
+# @name: the name of the CPU definition the model is based on
+# @props: a dictionary of QOM properties to be applied
+#
+# Since: 2.8
+##
+{ 'struct': 'CpuModelInfo',
+'data': { 'name': 'str',
+ '*props': 'any' } }
+
+##
+# @CpuModelExpansionType:
+#
+# An enumeration of CPU model expansion types.
+#
+# @static: Expand to a static CPU model, a combination of a static base
+# model name and property delta changes. As the static base model will
+# never change, the expanded CPU model will be the same, independent
of
+# QEMU version, machine type, machine options, and accelerator
options.
+# Therefore, the resulting model can be used by tooling without having
+# to specify a compatibility machine - e.g. when displaying the "host"
+# model. The @static CPU models are migration-safe.
+
+# @full: Expand all properties. The produced model is not guaranteed to be
+#migration-safe, but allows tooling to get an insight and work with
+#model details.
+#
+# Note: When a non-migration-safe CPU model is expanded in static mode, some
+# features enabled by the CPU model may be omitted, because they can't be
+# implemented by a static CPU model definition (e.g. cache info
passthrough and
+# PMU passthrough in x86). If you need an accurate representation of the
+# features enabled by a non-migration-safe CPU model, use @full. If you
need a
+# static representation that will keep ABI compatibility even when
changing QEMU
+# version or machine-type, use @static (but keep in mind that some
features may
+# be omitted).
+#
+# Since: 2.8
+##
+{ 'enum': 'CpuModelExpansionType',
+ 'data': [ 'static', 'full' ] }
+
+##
+# @CpuModelCompareResult:
+#
+# An enumeration of CPU model comparison results. The result is usually
+# calculated using e.g. CPU features or CPU generations.
+#
+# @incompatible: If model A is incompatible to model B, model A is not
+#guaranteed to run where model B runs and the other way around.
+#
+# @identical: If model A is identical to model B, model A is guaranteed to run
+# where model B runs and the other way around.
+#
+# @superset: If model A is a superset of model B, model B is guaranteed to run
+#where model A runs. There are no guarantees about the other way.
+#
+# @subset: If model A is a subset of model B, model A is guaranteed to run
+# where model B runs. There are no guarantees about the other way.
+#
+# Since: 2.8
+##
+{ 'enum': 'CpuModelCompareResult',
+ 'data': [ 'incompatible', 'identical', 'superset', 'subset' ] }
diff --git a/qapi/machine-target.json b/qapi/machine-target.json
index 2e267fa458..1cacfde88e 100644
--- a/qapi/machine-target.json
+++ b/qapi/machine-target.json
@@ -4,78 +4,7 @@
# This work is licensed under the terms of the GNU GPL, version 2 or later.
# See the COPYING file in the top-level directory.
-##
-# @CpuModelInfo:
-#
-# Virtual CPU model.
-#
-# A CPU model consists of the name of a CPU definition, to which
-# delta changes are applied (e.g. features added/removed). Most magic values
-# that an architecture might require should be hidden behind the name.
-# However, if required, architectures can expose relevant properties.
-#
-# @name: the name of the CPU
Re: [PATCH v2 1/3] qapi/machine-target: refactor machine-target
On 14/3/23 11:00, Dinah Baum wrote: Moved architecture agnostic data types to their own file to avoid "attempt to use poisoned TARGET_*" error that results when including qapi header with commands that aren't defined for all architectures. Required to implement enabling `query-cpu-model-expansion` on all architectures Signed-off-by: Dinah Baum --- MAINTAINERS | 1 + qapi/machine-target-common.json | 79 + qapi/machine-target.json| 73 +- qapi/meson.build| 1 + 4 files changed, 82 insertions(+), 72 deletions(-) create mode 100644 qapi/machine-target-common.json diff --git a/qapi/meson.build b/qapi/meson.build index 9fd480c4d8..48be47170f 100644 --- a/qapi/meson.build +++ b/qapi/meson.build @@ -38,6 +38,7 @@ qapi_all_modules = [ 'job', 'machine', 'machine-target', + 'machine-target-common', 'migration', 'misc', 'misc-target', Eh, this reminds me of https://lore.kernel.org/qemu-devel/20220204152924.6253-5-f4...@amsat.org/ I wonder between -common / -any / -all. Anyhow, Reviewed-by: Philippe Mathieu-Daudé
[PATCH v2 1/3] qapi/machine-target: refactor machine-target
Moved architecture agnostic data types to their own
file to avoid "attempt to use poisoned TARGET_*"
error that results when including qapi header
with commands that aren't defined for all architectures.
Required to implement enabling `query-cpu-model-expansion`
on all architectures
Signed-off-by: Dinah Baum
---
MAINTAINERS | 1 +
qapi/machine-target-common.json | 79 +
qapi/machine-target.json| 73 +-
qapi/meson.build| 1 +
4 files changed, 82 insertions(+), 72 deletions(-)
create mode 100644 qapi/machine-target-common.json
diff --git a/MAINTAINERS b/MAINTAINERS
index 95c957d587..bc4a6ba399 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1750,6 +1750,7 @@ F: hw/core/numa.c
F: hw/cpu/cluster.c
F: qapi/machine.json
F: qapi/machine-target.json
+F: qapi/machine-target-common.json
F: include/hw/boards.h
F: include/hw/core/cpu.h
F: include/hw/cpu/cluster.h
diff --git a/qapi/machine-target-common.json b/qapi/machine-target-common.json
new file mode 100644
index 00..1e6da3177d
--- /dev/null
+++ b/qapi/machine-target-common.json
@@ -0,0 +1,79 @@
+# -*- Mode: Python -*-
+# vim: filetype=python
+
+##
+# = Common data types for machine target commands
+##
+
+##
+# @CpuModelInfo:
+#
+# Virtual CPU model.
+#
+# A CPU model consists of the name of a CPU definition, to which
+# delta changes are applied (e.g. features added/removed). Most magic values
+# that an architecture might require should be hidden behind the name.
+# However, if required, architectures can expose relevant properties.
+#
+# @name: the name of the CPU definition the model is based on
+# @props: a dictionary of QOM properties to be applied
+#
+# Since: 2.8
+##
+{ 'struct': 'CpuModelInfo',
+'data': { 'name': 'str',
+ '*props': 'any' } }
+
+##
+# @CpuModelExpansionType:
+#
+# An enumeration of CPU model expansion types.
+#
+# @static: Expand to a static CPU model, a combination of a static base
+# model name and property delta changes. As the static base model will
+# never change, the expanded CPU model will be the same, independent
of
+# QEMU version, machine type, machine options, and accelerator
options.
+# Therefore, the resulting model can be used by tooling without having
+# to specify a compatibility machine - e.g. when displaying the "host"
+# model. The @static CPU models are migration-safe.
+
+# @full: Expand all properties. The produced model is not guaranteed to be
+#migration-safe, but allows tooling to get an insight and work with
+#model details.
+#
+# Note: When a non-migration-safe CPU model is expanded in static mode, some
+# features enabled by the CPU model may be omitted, because they can't be
+# implemented by a static CPU model definition (e.g. cache info
passthrough and
+# PMU passthrough in x86). If you need an accurate representation of the
+# features enabled by a non-migration-safe CPU model, use @full. If you
need a
+# static representation that will keep ABI compatibility even when
changing QEMU
+# version or machine-type, use @static (but keep in mind that some
features may
+# be omitted).
+#
+# Since: 2.8
+##
+{ 'enum': 'CpuModelExpansionType',
+ 'data': [ 'static', 'full' ] }
+
+##
+# @CpuModelCompareResult:
+#
+# An enumeration of CPU model comparison results. The result is usually
+# calculated using e.g. CPU features or CPU generations.
+#
+# @incompatible: If model A is incompatible to model B, model A is not
+#guaranteed to run where model B runs and the other way around.
+#
+# @identical: If model A is identical to model B, model A is guaranteed to run
+# where model B runs and the other way around.
+#
+# @superset: If model A is a superset of model B, model B is guaranteed to run
+#where model A runs. There are no guarantees about the other way.
+#
+# @subset: If model A is a subset of model B, model A is guaranteed to run
+# where model B runs. There are no guarantees about the other way.
+#
+# Since: 2.8
+##
+{ 'enum': 'CpuModelCompareResult',
+ 'data': [ 'incompatible', 'identical', 'superset', 'subset' ] }
diff --git a/qapi/machine-target.json b/qapi/machine-target.json
index 2e267fa458..1cacfde88e 100644
--- a/qapi/machine-target.json
+++ b/qapi/machine-target.json
@@ -4,78 +4,7 @@
# This work is licensed under the terms of the GNU GPL, version 2 or later.
# See the COPYING file in the top-level directory.
-##
-# @CpuModelInfo:
-#
-# Virtual CPU model.
-#
-# A CPU model consists of the name of a CPU definition, to which
-# delta changes are applied (e.g. features added/removed). Most magic values
-# that an architecture might require should be hidden behind the name.
-# However, if required, architectures can expose relevant properties.
-#
-# @name: the name of the CPU definition the model is based on
-# @
