Re: [PATCH v2 0/5] x86: cpuid: improve support for broken CPUID configurations

Maxim Levitsky
2022-08-01T16:05:46Z

On Thu, 2022-07-28 at 10:30 +0300, Maxim Levitsky wrote:
> On Mon, 2022-07-18 at 17:11 +0300, Maxim Levitsky wrote:
> > 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@gondor.apana.org.au/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(-)
> >
> > --
> > 2.34.3
> >
> >
> A very kind ping on these patches.

Another kind ping on these patches.

Best regards,
Maxim Levitsky
>
> Best regards,
> Maxim Levitsky