lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <f2cf136e-bf38-54ce-a0dc-31b0192d1dd6@linux.intel.com>
Date:   Wed, 23 Nov 2022 14:33:32 +0800
From:   Jiaxi Chen <jiaxi.chen@...ux.intel.com>
To:     Dave Hansen <dave.hansen@...el.com>
Cc:     kvm@...r.kernel.org, tglx@...utronix.de, mingo@...hat.com,
        bp@...en8.de, dave.hansen@...ux.intel.com, x86@...nel.org,
        hpa@...or.com, seanjc@...gle.com, pbonzini@...hat.com,
        ndesaulniers@...gle.com, alexandre.belloni@...tlin.com,
        peterz@...radead.org, jpoimboe@...nel.org,
        chang.seok.bae@...el.com, pawan.kumar.gupta@...ux.intel.com,
        babu.moger@....com, jmattson@...gle.com, sandipan.das@....com,
        tony.luck@...el.com, sathyanarayanan.kuppuswamy@...ux.intel.com,
        fenghua.yu@...el.com, keescook@...omium.org, nathan@...nel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 1/6] x86: KVM: Advertise CMPccXADD CPUID to user space



On 11/21/2022 11:29 PM, Dave Hansen wrote:
> On 11/21/22 06:46, Jiaxi Chen wrote:
>> Features which has been enabled in kernel usually should be added to
>> /proc/cpuinfo.
> 
> Features that the kernel *itself* is actually using always get in there.
>  Things like "smep".
> 
> But, things that the kernel "enables" but that only get used by
> userspace don't generally show up in /proc/cpuinfo.
> 
> KVM is kinda a weird case.  The kernel is making the feature available
> to guests, but it's not _using_ it in any meaningful way.  To me, this
> seems much more akin to the features that are just available to
> userspace than something that the kernel is truly using.
> 
> Also, these feature names are just long and ugly, and the "flags" line
> is already a human-*un*readable mess.  I think we should just leave them
> out.

True and agree. As for these cpuids are not truly used by kernel except
for advertising to kvm userspace, we can hide them in /proc/cpuinfo by
overriding their name with "".

-- 
Regards,
Jiaxi

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ