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From: Borislav Petkov <bp@alien8.de>
To: Maxim Levitsky <mlevitsk@redhat.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	Pawan Gupta <pawan.kumar.gupta@linux.intel.com>,
	Ingo Molnar <mingo@redhat.com>,
	Josh Poimboeuf <jpoimboe@kernel.org>,
	Namhyung Kim <namhyung@kernel.org>,
	Tony Luck <tony.luck@intel.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Tim Chen <tim.c.chen@linux.intel.com>,
	"David S. Miller" <davem@davemloft.net>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	"Chang S. Bae" <chang.seok.bae@intel.com>,
	Jane Malalane <jane.malalane@citrix.com>,
	Kees Cook <keescook@chromium.org>,
	Kan Liang <kan.liang@linux.intel.com>,
	Peter Zijlstra <peterz@infradead.org>,
	"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
	<x86@kernel.org>, Herbert Xu <herbert@gondor.apana.org.au>,
	Jiri Olsa <jolsa@kernel.org>, Mark Rutland <mark.rutland@arm.com>,
	linux-perf-users@vger.kernel.org,
	"open list:CRYPTO API" <linux-crypto@vger.kernel.org>
Subject: Re: [PATCH v2 1/5] perf/x86/intel/lbr: use setup_clear_cpu_cap instead of clear_cpu_cap
Date: Thu, 20 Oct 2022 10:59:48 +0200	[thread overview]
Message-ID: <Y1EOBAaLbv2CXBDL@zn.tnic> (raw)
In-Reply-To: <c1168e8bd9077a2cc9ef61ee06db7a4e8c0f1600.camel@redhat.com>

On Wed, Sep 28, 2022 at 01:49:34PM +0300, Maxim Levitsky wrote:
> Patch 5 is the main fix - it makes the kernel to be tolerant to a
> broken CPUID config (coming hopefully from hypervisor), where you have
> a feature (AVX2 in my case) but not a feature on which this feature
> depends (AVX).

I really really don't like it when people are fixing the wrong thing.

Why does the kernel need to get fixed when something else can't get its
CPUID dependencies straight? I don't even want to know why something
would set AVX2 without AVX?!?!

Srsly.

Some of your other bits look sensible and I'd take a deeper look but
this does not make any sense. This is a hypervisor problem - not a
kernel one.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette

  reply	other threads:[~2022-10-20  9:00 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-18 14:11 [PATCH v2 0/5] x86: cpuid: improve support for broken CPUID configurations Maxim Levitsky
2022-07-18 14:11 ` [PATCH v2 1/5] perf/x86/intel/lbr: use setup_clear_cpu_cap instead of clear_cpu_cap Maxim Levitsky
2022-09-19 14:31   ` Borislav Petkov
2022-09-20  8:20     ` Maxim Levitsky
2022-09-26 13:12       ` Borislav Petkov
2022-09-28 10:49         ` Maxim Levitsky
2022-10-20  8:59           ` Borislav Petkov [this message]
2022-10-20  9:05             ` Herbert Xu
2022-10-20 10:21               ` Maxim Levitsky
2022-10-20 11:13                 ` Borislav Petkov
2022-10-22 21:08             ` H. Peter Anvin
2022-11-02 13:40             ` Paolo Bonzini
2022-11-02 14:27               ` Elliott, Robert (Servers)
2022-11-02 16:23                 ` H. Peter Anvin
2022-11-02 18:19                   ` H. Peter Anvin
2022-11-02 19:14                     ` Elliott, Robert (Servers)
2022-11-03 13:26                   ` Paolo Bonzini
2022-11-03 13:30                 ` Paolo Bonzini
2022-07-18 14:11 ` [PATCH v2 2/5] x86/cpuid: refactor setup_clear_cpu_cap()/clear_cpu_cap() Maxim Levitsky
2022-10-21 16:19   ` Borislav Petkov
2022-11-07 19:10     ` Borislav Petkov
2022-11-07 21:57       ` Borislav Petkov
2022-07-18 14:11 ` [PATCH v2 3/5] x86/cpuid: move filter_cpuid_features to cpuid-deps.c Maxim Levitsky
2022-07-18 14:11 ` [PATCH v2 4/5] x86/cpuid: remove 'warn' parameter from filter_cpuid_features Maxim Levitsky
2022-07-18 14:11 ` [PATCH v2 5/5] x86/cpuid: check for dependencies violations in CPUID and attempt to fix them Maxim Levitsky
2022-07-28  7:30 ` [PATCH v2 0/5] x86: cpuid: improve support for broken CPUID configurations Maxim Levitsky
2022-08-01 16:05   ` Maxim Levitsky
2022-08-01 16:31     ` Dave Hansen
2022-08-01 16:41       ` Maxim Levitsky
2022-09-19 13:43     ` Maxim Levitsky

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