2022-07-28 07:35:10

by Maxim Levitsky

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

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/[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(-)
>
> --
> 2.34.3
>
>
A very kind ping on these patches.

Best regards,
Maxim Levitsky


2022-08-01 16:09:20

by Maxim Levitsky

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

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/[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(-)
> >
> > --
> > 2.34.3
> >
> >
> A very kind ping on these patches.

Another kind ping on these patches.


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



2022-08-01 16:36:53

by Dave Hansen

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

On 8/1/22 09:05, Maxim Levitsky wrote:
>> A very kind ping on these patches.
> Another kind ping on these patches.

Maxim,

This series is not forgotten. Its latest version was simply posted too
close to the merge window. It'll get looked at in a week or two when
things calm down.

Please be patient.

2022-08-01 16:43:47

by Maxim Levitsky

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

On Mon, 2022-08-01 at 09:31 -0700, Dave Hansen wrote:
> On 8/1/22 09:05, Maxim Levitsky wrote:
> > > A very kind ping on these patches.
> > Another kind ping on these patches.
>
> Maxim,
>
> This series is not forgotten. Its latest version was simply posted too
> close to the merge window. It'll get looked at in a week or two when
> things calm down.
>
> Please be patient.
>

Thanks!

Best regards,
Maxim Levitsky