[uq/master PATCH 0/7] x86 CPU subclasses, take 7

Eduardo Habkost
2014-01-30T19:49:06Z

Is there any hope to get this into QEMU 2.0, or it is now too late? I got
almost no feedback on take 6 (submitted November 27).

This is the main blocker to allow libvirt finally implement an equivalent to the
"enforce" flag, finally making the CPU configuration safe and sane (today
libvirt simply ignores GET_SUPPORTED_CPUID information, and features are
silently disabled because "enforce" is not used).

This blocks libvirt because the current available interfaces requires re-running
QEMU for each CPU model to be probed. Having the x86 CPU subclasses allow
libvirt to simply create and destroy CPU objects from each available CPU class,
and query for the results using QMP.

Demonstration of how this can be used, below:

Running QEMU as:
$ qemu-system-x86_64 -enable-kvm -machine none -monitor stdio -qmp unix:/tmp/qmp,server,nowait -nographic

Then running qmp-shell as:
$ ./scripts/qmp/qmp-shell /tmp/qmp
[...]
(QEMU) object-add qom-type=host-x86_64-cpu id=probing-host-cpu-type
{u'return': {}}
(QEMU) object-add qom-type=Nehalem-x86_64-cpu id=probing-cpu-type-Nehalem
{u'return': {}}
(QEMU) object-add qom-type=Westmere-x86_64-cpu id=probing-cpu-type-Westmere
{u'return': {}}
(QEMU) object-add qom-type=Haswell-x86_64-cpu id=probing-cpu-type-Haswell
(QEMU) qom-list path=/objects/
{u'return': [{u'type': u'child<Haswell-x86_64-cpu>', u'name': u'probing-cpu-type-Haswell'}, {u'type': u'child<Westmere-x86_64-cpu>', u'name': u'probing-cpu-type-Westmere'}, {u'type': u'child<Nehalem-x86_64-cpu>', u'name': u'probing-cpu-type-Nehalem'}, {u'type': u'child<host-x86_64-cpu>', u'name': u'probing-host-cpu-type'}, {u'type': u'string', u'name': u'type'}]}
(QEMU) qom-list path=/objects/probing-cpu-type-Haswell/
{u'return': [{u'type': u'X86CPUFeatureWordInfo', u'name': u'filtered-features'}, {u'type': u'X86CPUFeatureWordInfo', u'name': u'feature-words'}, {u'type': u'int', u'name': u'apic-id'}, {u'type': u'int', u'name': u'tsc-frequency'}, {u'type': u'string', u'name': u'model-id'}, {u'type': u'string', u'name': u'vendor'}, {u'type': u'int', u'name': u'xlevel'}, {u'type': u'int', u'name': u'level'}, {u'type': u'int', u'name': u'stepping'}, {u'type': u'int', u'name': u'model'}, {u'type': u'int', u'name': u'family'}, {u'type': u'link<bus>', u'name': u'parent_bus'}, {u'type': u'boolean', u'name': u'enforce'}, {u'type': u'boolean', u'name': u'check'}, {u'type': u'boolean', u'name': u'hv-time'}, {u'type': u'boolean', u'name': u'hv-vapic'}, {u'type': u'boolean', u'name': u'hv-relaxed'}, {u'type': u'int',
u'name': u'hv-spinlocks'}, {u'type': u'boolean', u'name': u'pmu'}, {u'type': u'bool', u'name': u'realized'}, {u'type': u'string', u'name': u'type'}]}
(QEMU) qom-get path=/objects/probing-cpu-type-Haswell property=feature-words
{u'return': [{u'cpuid-register': u'EDX', u'cpuid-input-eax': 2147483658, u'features': 0}, {u'cpuid-register': u'EAX', u'cpuid-input-eax': 1073741825, u'features': 16777339}, {u'cpuid-register': u'EDX', u'cpuid-input-eax': 3221225473, u'features': 0}, {u'cpuid-register': u'ECX', u'cpuid-input-eax': 2147483649, u'features': 1}, {u'cpuid-register': u'EDX', u'cpuid-input-eax': 2147483649, u'features': 672139264}, {u'cpuid-register': u'EBX', u'cpuid-input-eax': 7, u'features': 4025, u'cpuid-input-ecx': 0}, {u'cpuid-register': u'ECX', u'cpuid-input-eax': 1, u'features': 2549756419}, {u'cpuid-register': u'EDX', u'cpuid-input-eax': 1, u'features': 126614525}]}
(QEMU) qom-get path=/objects/probing-cpu-type-Haswell property=filtered-features
{u'return': [{u'cpuid-register': u'EDX', u'cpuid-input-eax': 2147483658, u'features': 0}, {u'cpuid-register': u'EAX', u'cpuid-input-eax': 1073741825, u'features': 0}, {u'cpuid-register': u'EDX', u'cpuid-input-eax': 3221225473, u'features': 0}, {u'cpuid-register': u'ECX', u'cpuid-input-eax': 2147483649, u'features': 0}, {u'cpuid-register': u'EDX', u'cpuid-input-eax': 2147483649, u'features': 0}, {u'cpuid-register': u'EBX', u'cpuid-input-eax': 7, u'features': 0, u'cpuid-input-ecx': 0}, {u'cpuid-register': u'ECX', u'cpuid-input-eax': 1, u'features': 0}, {u'cpuid-register': u'EDX', u'cpuid-input-eax': 1, u'features': 0}]}
(QEMU) qom-get path=/objects/probing-host-cpu-type property=feature-words
{u'return': [{u'cpuid-register': u'EDX', u'cpuid-input-eax': 2147483658, u'features': 0}, {u'cpuid-register': u'EAX', u'cpuid-input-eax': 1073741825, u'features': 16777467}, {u'cpuid-register': u'EDX', u'cpuid-input-eax': 3221225473, u'features': 0}, {u'cpuid-register': u'ECX', u'cpuid-input-eax': 2147483649, u'features': 1}, {u'cpuid-register': u'EDX', u'cpuid-input-eax': 2147483649, u'features': 697564159}, {u'cpuid-register': u'EBX', u'cpuid-input-eax': 7, u'features': 2, u'cpuid-input-ecx': 0}, {u'cpuid-register': u'ECX', u'cpuid-input-eax': 1, u'features': 2193236483}, {u'cpuid-register': u'EDX', u'cpuid-input-eax': 1, u'features': 260832255}]}
(QEMU) qom-get path=/objects/probing-host-cpu-type property=filtered-features
{u'return': [{u'cpuid-register': u'EDX', u'cpuid-input-eax': 2147483658, u'features': 0}, {u'cpuid-register': u'EAX', u'cpuid-input-eax': 1073741825, u'features': 0}, {u'cpuid-register': u'EDX', u'cpuid-input-eax': 3221225473, u'features': 0}, {u'cpuid-register': u'ECX', u'cpuid-input-eax': 2147483649, u'features': 0}, {u'cpuid-register': u'EDX', u'cpuid-input-eax': 2147483649, u'features': 0}, {u'cpuid-register': u'EBX', u'cpuid-input-eax': 7, u'features': 0, u'cpuid-input-ecx': 0}, {u'cpuid-register': u'ECX', u'cpuid-input-eax': 1, u'features': 0}, {u'cpuid-register': u'EDX', u'cpuid-input-eax': 1, u'features': 0}]}

Changes from take 6:

* Rebase against uq/master
* Patch 1/7:
* Check for __i386__ on host_cpuid() so the code compiles properly
on non-x86 hosts.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
* Don't add assert(kvm_enabled()) line, which is not necessary to help
the compiler (and wouldn't help it if using -DNDEBUG, anyway).
Reported-by: Richard Henderson <rth@twiddle.net>
* Commit message update

Eduardo Habkost (7):
target-i386: Eliminate CONFIG_KVM #ifdefs
target-i386: Don't change x86_def_t struct on cpu_x86_register()
target-i386: Move KVM default-vendor hack to instance_init
target-i386: Rename cpu_x86_register() to x86_cpu_load_def()
target-i386: Call x86_cpu_load_def() earlier
target-i386: Rename x86_def_t to X86CPUDefinition
target-i386: CPU model subclasses

target-i386/cpu-qom.h | 13 ++
target-i386/cpu.c | 402 ++++++++++++++++++++++++++++++--------------------
target-i386/cpu.h | 2 -
3 files changed, 256 insertions(+), 161 deletions(-)

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1.8.4.2