Re: [libvirt] [Qemu-devel] [PATCH qom-cpu 6/9] target-i386: Add "feature-words" property
On 04/22/2013 01:00 PM, Eduardo Habkost wrote:
This property will be useful for libvirt, as libvirt already has
logic
based on low-level feature bits (not feature names), so it will be
really easy to convert the current libvirt logic to something using the
"feature-words" property.
The property will have two main use cases:
- Checking host capabilities, by checking the features of the "host"
CPU model
- Checking which features are enabled on each CPU model
item[6].cpuid-register: ECX
item[6].cpuid-input-eax: 1
item[6].features: 2155880449
item[7].cpuid-register: EDX
item[7].cpuid-input-eax: 1
item[7].features: 126614521
I'm guessing the corresponding JSON passed over QMP would look something
like:
[ ...
{ "cpuid-register": "ECX",
"cpuid-input-eax": 1,
"features": 2155880449 },
{ "cpuid-register": "EDX",
"cpuid-input-eax": 1,
"features": 126614521 } ]
which libvirt can reasonably parse.
Signed-off-by: Eduardo Habkost <ehabkost(a)redhat.com>
---
Changes v1 -> v2:
* Merge the non-qapi and qapi patches, to keep series simpler
* Use the feature word array series as base, so we don't have
to set the feature word values one-by-one in the code
* Change type name of property from "x86-cpu-feature-words" to
"X86CPUFeatureWordInfo"
* Remove cpu-qapi-schema.json and simply add the type definitions
to qapi-schema.json, to keep the changes simpler
* This required compiling qapi-types.o and qapi-visit.o into
*-user as well
---
.gitignore | 2 ++
Makefile.objs | 7 +++++-
qapi-schema.json | 31 ++++++++++++++++++++++++
target-i386/cpu.c | 70 +++++++++++++++++++++++++++++++++++++++++++++----------
4 files changed, 97 insertions(+), 13 deletions(-)
I'm not sure I'm the best person to review cpu.c, but I can at least
review the interface from what libvirt plans on using:
+++ b/qapi-schema.json
@@ -3505,3 +3505,34 @@
'*asl_compiler_rev': 'uint32',
'*file': 'str',
'*data': 'str' }}
+
+# @X86CPURegister32
+#
+# A X86 32-bit register
+#
+# Since: 1.5
Yes, I'd still like to get this into 1.5. On some enums, we have called
out doc-text for each enum value; but I'm fine with your choice here to
omit that.
+##
+{ 'enum': 'X86CPURegister32',
+ 'data': [ 'EAX', 'EBX', 'ECX', 'EDX',
'ESP', 'EBP', 'ESI', 'EDI' ] }
Any reason you favored ALL-CAPS names? But it doesn't matter to me, as
long as we stick to the name once baked into a release.
+
+##
+# @X86CPUFeatureWordInfo
+#
+# Information about a X86 CPU feature word
+#
+# @cpuid-input-eax: Input EAX value for CPUID instruction for that feature word
+#
+# @cpuid-input-ecx: #optional Input ECX value for CPUID instruction for that
+# feature word
+#
+# @cpuid-register: Output register containing the feature bits
+#
+# @features: value of output register, containing the feature bits
+#
+# Since: 1.5
+##
+{ 'type': 'X86CPUFeatureWordInfo',
+ 'data': { 'cpuid-input-eax': 'int',
+ '*cpuid-input-ecx': 'int',
+ 'cpuid-register': 'X86CPURegister32',
+ 'features': 'int' } }
Looks reasonable for the interface side of things.
+static void x86_cpu_get_feature_words(Object *obj, Visitor *v, void *opaque,
+ const char *name, Error **errp)
Indentation looks off.
Reviewed-by: Eric Blake <eblake(a)redhat.com>
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
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