[v7,0/1] qapi: introduce 'query-cpu-model-cpuid' action

Message

Valeriy Vdovin May 4, 2021, 12:26 p.m. UTC

In version 7 of the subject patch, I wanted to try to implement this qmp
method with the help of existing kvm ioctl KVM_GET_CPUID2. The reasoning
behind my decision is the fact that QEMU uses KVM_SET_CPUID2 to set full
cpuid response table to the virtual cpu, and KVM_GET_CPUID2 is a convenient
and complementary method for extracting the same cpuid entry table back
from the kernel.

So I've pushed a patch into Linux KVM subtree to fine tune ioctl
KVM_GET_CPUID2 for this type of application. This has triggered a small
discussion.
One of the responses here https://lkml.org/lkml/2021/5/4/109 is from
Paolo Bonzini. There he suggests to cache the the whole cpuid entries
table that we pass to the kernel via KVM_SET_CPUID2 and later just output
this cached data instead of calling the same table via KVM_GET_CPUID2.
Current patch is the reflection of that idea.

Valeriy Vdovin (1):
  qapi: introduce 'query-cpu-model-cpuid' action

 qapi/machine-target.json   | 51 ++++++++++++++++++++++++++++++++++++++
 target/i386/kvm/kvm.c      | 45 ++++++++++++++++++++++++++++++---
 tests/qtest/qmp-cmd-test.c |  1 +
 3 files changed, 93 insertions(+), 4 deletions(-)