From: Thomas Gleixner <tglx@linutronix.de>
To: Borislav Petkov <bp@alien8.de>
Cc: Feng Tang <feng.tang@intel.com>, Ingo Molnar <mingo@redhat.com>,
"H . Peter Anvin" <hpa@zytor.com>,
Peter Zijlstra <peterz@infradead.org>,
x86@kernel.org, linux-kernel@vger.kernel.org,
rui.zhang@intel.com, andi.kleen@intel.com, dave.hansen@intel.com,
len.brown@intel.com
Subject: Re: [RFC 1/2] x86/tsc: add a timer to make sure tsc_adjust is always checked
Date: Sat, 10 Apr 2021 20:43:27 +0200 [thread overview]
Message-ID: <87fszy2d68.ffs@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20210410094752.GB21691@zn.tnic>
On Sat, Apr 10 2021 at 11:47, Borislav Petkov wrote:
> On Sat, Apr 10, 2021 at 11:27:11AM +0200, Thomas Gleixner wrote:
>> On Tue, Mar 30 2021 at 16:25, Feng Tang wrote:
>> > Normally the tsc_sync will be checked every time system enters idle state,
>> > but there is still caveat that a system won't enter idle, either because
>> > it's too busy or configured purposely to not enter idle. Setup a periodic
>> > timer to make sure the check is always on.
>>
>> Bah. I really hate the fact that we don't have a knob to disable writes
>> to the TSC/TSC_ADJUST msrs. That would spare this business alltogether.
>
> We have the MSR filtering and I'd *love* to add those MSRs to a
> permanent ban list of MSRs which will never ever be written to from
> luserspace.
That's good, but what I really want is a knob which prevents BIOS/SMM
from writing to it. The only reason why BIOS ever needs to write is for
physical hotplug and perhaps for 4+ socket machines on boot. After that
every write is a bug.
Thanks,
tglx
next prev parent reply other threads:[~2021-04-10 18:43 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-30 8:25 [RFC 1/2] x86/tsc: add a timer to make sure tsc_adjust is always checked Feng Tang
2021-03-30 8:25 ` [RFC 2/2] x86/tsc: mark tsc reliable for qualified platforms Feng Tang
2021-04-10 9:27 ` [RFC 1/2] x86/tsc: add a timer to make sure tsc_adjust is always checked Thomas Gleixner
2021-04-10 9:47 ` Borislav Petkov
2021-04-10 12:11 ` [PATCH] x86/msr: Block writes to certain MSRs unconditionally Borislav Petkov
2021-04-10 14:51 ` Andy Lutomirski
2021-04-10 15:33 ` [PATCH -v1.1] " Borislav Petkov
2021-04-10 18:52 ` [PATCH] " Andi Kleen
2021-04-11 9:40 ` Borislav Petkov
2021-04-11 16:03 ` Andy Lutomirski
2021-04-11 16:43 ` Andi Kleen
2021-04-11 16:57 ` Andy Lutomirski
2021-04-11 17:03 ` Borislav Petkov
2021-04-11 23:21 ` Andy Lutomirski
2021-04-12 9:37 ` Borislav Petkov
2021-04-10 14:48 ` [RFC 1/2] x86/tsc: add a timer to make sure tsc_adjust is always checked Feng Tang
2021-04-10 15:38 ` Borislav Petkov
2021-04-10 18:43 ` Thomas Gleixner [this message]
2021-04-10 14:38 ` Feng Tang
2021-04-10 18:46 ` Thomas Gleixner
2021-04-11 7:21 ` Feng Tang
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87fszy2d68.ffs@nanos.tec.linutronix.de \
--to=tglx@linutronix.de \
--cc=andi.kleen@intel.com \
--cc=bp@alien8.de \
--cc=dave.hansen@intel.com \
--cc=feng.tang@intel.com \
--cc=hpa@zytor.com \
--cc=len.brown@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=rui.zhang@intel.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.