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/20211103145231.GA4485@xxxxxxxxxxxxxxxxxxx/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. Best regards, Maxim Levitsky Maxim Levitsky (4): perf/x86/intel/lbr: use setup_clear_cpu_cap instead of clear_cpu_cap x86/cpuid: refactor setup_clear_cpu_cap/clear_feature x86/cpuid: move filter_cpuid_features to cpuid-deps.c 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 | 50 +----------------- arch/x86/kernel/cpu/cpuid-deps.c | 84 +++++++++++++++++++++++++++---- 4 files changed, 78 insertions(+), 59 deletions(-) -- 2.26.3
