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SubjectRe: [PATCH 0/5] KVM: x86: Use kernel x86 cpuid utilities in KVM selftests
On Thu, Apr 22, 2021 at 09:02:09AM +0200, Paolo Bonzini wrote:
> On 22/04/21 02:56, Ricardo Koller wrote:
> > The kernel has a set of utilities and definitions to deal with x86 cpu
> > features. The x86 KVM selftests don't use them, and instead have
> > evolved to use differing and ad-hoc methods for checking features. The
> > advantage of the kernel feature definitions is that they use a format
> > that embeds the info needed to extract them from cpuid (function, index,
> > and register to use).
> >
> > The first 3 patches massage the related cpuid header files in the kernel
> > side, then copy them into tools/ so they can be included by selftests.
> > The last 2 patches replace the tests checking for cpu features to use
> > the definitions and utilities introduced from the kernel.
>
> I queued the first, but I am not sure about the rest.
>
> An alternative is to copy over the code from kvm-unit-tests which encodes
> the leaf/subleaf/register/bit values into the X86_FEATURE_* value. Sharing
> code with kvm-unit-tests is probably simpler than adding #ifdef __KERNEL__
> and keeping the headers in sync.
>
> Paolo
>

Thanks. I was thinking about kvm-unit-tests, but the issue is that it
would also be a copy. And just like with kernel headers, it would be
ideal to keep them in-sync. The advantage of the kernel headers is that
it's much easier to check and fix diffs with them. On the other hand, as
you say, there would not be any #ifdef stuff with kvm=unit-tests. Please
let me know what you think.

Thanks,
Ricardo

> > Thanks,
> > Ricardo
> >
> > Ricardo Koller (5):
> > KVM: x86: Move reverse CPUID helpers to separate header file
> > x86/cpu: Expose CPUID regs, leaf and index definitions to tools
> > tools headers x86: Copy cpuid helpers from the kernel
> > KVM: selftests: Introduce utilities for checking x86 features
> > KVM: selftests: Use kernel x86 cpuid features format
> >
> > arch/x86/events/intel/pt.c | 1 +
> > arch/x86/include/asm/cpufeature.h | 23 +-
> > arch/x86/include/asm/processor.h | 11 -
> > arch/x86/kernel/cpu/scattered.c | 2 +-
> > arch/x86/kernel/cpuid.c | 2 +-
> > arch/x86/kvm/cpuid.h | 177 +-----------
> > arch/x86/kvm/reverse_cpuid.h | 185 +++++++++++++
> > tools/arch/x86/include/asm/cpufeature.h | 257 ++++++++++++++++++
> > tools/arch/x86/include/asm/cpufeatures.h | 3 +
> > .../selftests/kvm/include/x86_64/cpuid.h | 61 +++++
> > .../selftests/kvm/include/x86_64/processor.h | 16 --
> > .../kvm/include/x86_64/reverse_cpuid.h | 185 +++++++++++++
> > .../selftests/kvm/include/x86_64/svm_util.h | 11 +-
> > tools/testing/selftests/kvm/lib/x86_64/svm.c | 6 +-
> > tools/testing/selftests/kvm/lib/x86_64/vmx.c | 5 +-
> > tools/testing/selftests/kvm/steal_time.c | 5 +-
> > .../kvm/x86_64/cr4_cpuid_sync_test.c | 23 +-
> > .../selftests/kvm/x86_64/set_sregs_test.c | 25 +-
> > .../selftests/kvm/x86_64/vmx_pmu_msrs_test.c | 8 +-
> > .../kvm/x86_64/vmx_set_nested_state_test.c | 5 +-
> > .../selftests/kvm/x86_64/xss_msr_test.c | 10 +-
> > 21 files changed, 749 insertions(+), 272 deletions(-)
> > create mode 100644 arch/x86/kvm/reverse_cpuid.h
> > create mode 100644 tools/arch/x86/include/asm/cpufeature.h
> > create mode 100644 tools/testing/selftests/kvm/include/x86_64/cpuid.h
> > create mode 100644 tools/testing/selftests/kvm/include/x86_64/reverse_cpuid.h
> >
>

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