This patch series aims to harden the cpuid code against the case when
the hypervisor exposes a broken CPUID configuration to the guest,
in the form of having a feature disabled but not features that depend on it.
This is the more generic way to fix kernel panic in aes-ni kernel driver,
which was triggered by CPUID configuration in which AVX is disabled but
not AVX2.
https://lore.kernel.org/all/[email protected]/T/
This was tested by booting a guest with AVX disabled and not AVX2,
and observing that both a warning is now printed in dmesg, and
that avx2 is gone from /proc/cpuinfo.
V2:
I hopefully addressed all the (very good) review feedback.
Best regards,
Maxim Levitsky
Maxim Levitsky (5):
perf/x86/intel/lbr: use setup_clear_cpu_cap instead of clear_cpu_cap
x86/cpuid: refactor setup_clear_cpu_cap()/clear_cpu_cap()
x86/cpuid: move filter_cpuid_features to cpuid-deps.c
x86/cpuid: remove 'warn' parameter from filter_cpuid_features
x86/cpuid: check for dependencies violations in CPUID and attempt to
fix them
arch/x86/events/intel/lbr.c | 2 +-
arch/x86/include/asm/cpufeature.h | 1 +
arch/x86/kernel/cpu/common.c | 51 +-------------------
arch/x86/kernel/cpu/cpuid-deps.c | 80 +++++++++++++++++++++++++++----
4 files changed, 74 insertions(+), 60 deletions(-)
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2.34.3