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

Maxim Levitsky
2022-09-19T13:43:21Z

On Mon, 2022-08-01 at 19:05 +0300, Maxim Levitsky wrote:
> 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.

Another very gentle ping on these patches.

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