All of lore.kernel.org
 help / color / mirror / Atom feed
From: Dave Hansen <dave.hansen@intel.com>
To: Ira Weiny <ira.weiny@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Andy Lutomirski <luto@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Fenghua Yu <fenghua.yu@intel.com>,
	x86@kernel.org, linux-kernel@vger.kernel.org,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-doc@vger.kernel.org, linux-nvdimm@lists.01.org,
	linux-mm@kvack.org, linux-kselftest@vger.kernel.org,
	Greg KH <gregkh@linuxfoundation.org>
Subject: Re: [NEEDS-REVIEW] [PATCH V3 04/10] x86/pks: Preserve the PKRS MSR on context switch
Date: Fri, 18 Dec 2020 07:33:03 -0800	[thread overview]
Message-ID: <7666e039-d005-a732-7ec9-35ac7f36ead3@intel.com> (raw)
In-Reply-To: <20201218041012.GC2506510@iweiny-DESK2.sc.intel.com>

On 12/17/20 8:10 PM, Ira Weiny wrote:
> On Thu, Dec 17, 2020 at 12:41:50PM -0800, Dave Hansen wrote:
>> On 11/6/20 3:29 PM, ira.weiny@intel.com wrote:
>>>  void disable_TSC(void)
>>> @@ -644,6 +668,8 @@ void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p)
>>>  
>>>  	if ((tifp ^ tifn) & _TIF_SLD)
>>>  		switch_to_sld(tifn);
>>> +
>>> +	pks_sched_in();
>>>  }
>>
>> Does the selftest for this ever actually schedule()?
> 
> At this point I'm not sure.  This code has been in since the beginning.  So its
> seen a lot of soak time.

Think about it another way.  Let's say this didn't get called on the
first context switch away from the PKS-using task.  Would anyone notice?
 How likely is this to happen?

The function tracers or kprobes tend to be a great tool for this, at
least for testing whether the code path you expect to hit is getting hit.
_______________________________________________
Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org
To unsubscribe send an email to linux-nvdimm-leave@lists.01.org

WARNING: multiple messages have this Message-ID (diff)
From: Dave Hansen <dave.hansen@intel.com>
To: Ira Weiny <ira.weiny@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Andy Lutomirski <luto@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Fenghua Yu <fenghua.yu@intel.com>,
	x86@kernel.org, linux-kernel@vger.kernel.org,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-doc@vger.kernel.org, linux-nvdimm@lists.01.org,
	linux-mm@kvack.org, linux-kselftest@vger.kernel.org,
	Dan Williams <dan.j.williams@intel.com>,
	Greg KH <gregkh@linuxfoundation.org>
Subject: Re: [NEEDS-REVIEW] [PATCH V3 04/10] x86/pks: Preserve the PKRS MSR on context switch
Date: Fri, 18 Dec 2020 07:33:03 -0800	[thread overview]
Message-ID: <7666e039-d005-a732-7ec9-35ac7f36ead3@intel.com> (raw)
In-Reply-To: <20201218041012.GC2506510@iweiny-DESK2.sc.intel.com>

On 12/17/20 8:10 PM, Ira Weiny wrote:
> On Thu, Dec 17, 2020 at 12:41:50PM -0800, Dave Hansen wrote:
>> On 11/6/20 3:29 PM, ira.weiny@intel.com wrote:
>>>  void disable_TSC(void)
>>> @@ -644,6 +668,8 @@ void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p)
>>>  
>>>  	if ((tifp ^ tifn) & _TIF_SLD)
>>>  		switch_to_sld(tifn);
>>> +
>>> +	pks_sched_in();
>>>  }
>>
>> Does the selftest for this ever actually schedule()?
> 
> At this point I'm not sure.  This code has been in since the beginning.  So its
> seen a lot of soak time.

Think about it another way.  Let's say this didn't get called on the
first context switch away from the PKS-using task.  Would anyone notice?
 How likely is this to happen?

The function tracers or kprobes tend to be a great tool for this, at
least for testing whether the code path you expect to hit is getting hit.


  reply	other threads:[~2020-12-18 15:33 UTC|newest]

Thread overview: 100+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-06 23:28 [PATCH V3 00/10] PKS: Add Protection Keys Supervisor (PKS) support V3 ira.weiny
2020-11-06 23:28 ` ira.weiny
2020-11-06 23:28 ` [PATCH V3 01/10] x86/pkeys: Create pkeys_common.h ira.weiny
2020-11-06 23:28   ` ira.weiny
2020-11-06 23:29 ` [PATCH V3 02/10] x86/fpu: Refactor arch_set_user_pkey_access() for PKS support ira.weiny
2020-11-06 23:29   ` ira.weiny
2020-11-06 23:29 ` [PATCH V3 03/10] x86/pks: Add PKS defines and Kconfig options ira.weiny
2020-11-06 23:29   ` ira.weiny
2020-11-06 23:29 ` [PATCH V3 04/10] x86/pks: Preserve the PKRS MSR on context switch ira.weiny
2020-11-06 23:29   ` ira.weiny
2020-12-17 14:50   ` Thomas Gleixner
2020-12-17 14:50     ` Thomas Gleixner
2020-12-17 22:43     ` Thomas Gleixner
2020-12-17 22:43       ` Thomas Gleixner
2020-12-18 13:57       ` Thomas Gleixner
2020-12-18 13:57         ` Thomas Gleixner
2020-12-18 19:20         ` Dan Williams
2020-12-18 19:20           ` Dan Williams
2020-12-18 19:20           ` Dan Williams
2020-12-18 21:06           ` Thomas Gleixner
2020-12-18 21:06             ` Thomas Gleixner
2020-12-18 21:58             ` Dan Williams
2020-12-18 21:58               ` Dan Williams
2020-12-18 21:58               ` Dan Williams
2020-12-18 22:44               ` Thomas Gleixner
2020-12-18 22:44                 ` Thomas Gleixner
2020-12-18 19:42         ` Ira Weiny
2020-12-18 19:42           ` Ira Weiny
2020-12-18 20:10           ` Dave Hansen
2020-12-18 20:10             ` Dave Hansen
2020-12-18 21:30           ` Thomas Gleixner
2020-12-18 21:30             ` Thomas Gleixner
2020-12-18  4:05     ` Ira Weiny
2020-12-18  4:05       ` Ira Weiny
2020-12-17 20:41   ` [NEEDS-REVIEW] " Dave Hansen
2020-12-17 20:41     ` Dave Hansen
2020-12-18  4:10     ` Ira Weiny
2020-12-18  4:10       ` Ira Weiny
2020-12-18 15:33       ` Dave Hansen [this message]
2020-12-18 15:33         ` Dave Hansen
2020-11-06 23:29 ` [PATCH V3 05/10] x86/entry: Pass irqentry_state_t by reference ira.weiny
2020-11-06 23:29   ` ira.weiny
2020-11-15 18:58   ` Thomas Gleixner
2020-11-15 18:58     ` Thomas Gleixner
2020-11-16 18:49     ` Ira Weiny
2020-11-16 18:49       ` Ira Weiny
2020-11-16 20:36       ` Thomas Gleixner
2020-11-16 20:36         ` Thomas Gleixner
2020-11-24  6:09   ` [PATCH V3.1] entry: " ira.weiny
2020-11-24  6:09     ` ira.weiny
2020-12-11 22:14     ` Andy Lutomirski
2020-12-11 22:14       ` Andy Lutomirski
2020-12-11 22:14       ` Andy Lutomirski
2020-12-16  1:32       ` Ira Weiny
2020-12-16  1:32         ` Ira Weiny
2020-12-16  1:32         ` Ira Weiny
2020-12-16  2:09         ` Andy Lutomirski
2020-12-16  2:09           ` Andy Lutomirski
2020-12-16  2:09           ` Andy Lutomirski
2020-12-17  0:38           ` Ira Weiny
2020-12-17  0:38             ` Ira Weiny
2020-12-17  0:38             ` Ira Weiny
2020-12-17 13:07       ` Thomas Gleixner
2020-12-17 13:07         ` Thomas Gleixner
2020-12-17 13:07         ` Thomas Gleixner
2020-12-17 13:19         ` Peter Zijlstra
2020-12-17 13:19           ` Peter Zijlstra
2020-12-17 13:19           ` Peter Zijlstra
2020-12-17 15:35           ` Andy Lutomirski
2020-12-17 15:35             ` Andy Lutomirski
2020-12-17 15:35             ` Andy Lutomirski
2020-12-17 16:58     ` Thomas Gleixner
2020-12-17 16:58       ` Thomas Gleixner
2020-11-06 23:29 ` [PATCH V3 06/10] x86/entry: Preserve PKRS MSR across exceptions ira.weiny
2020-11-06 23:29   ` ira.weiny
2020-12-17 15:28   ` Thomas Gleixner
2020-12-17 15:28     ` Thomas Gleixner
2020-11-06 23:29 ` [PATCH V3 07/10] x86/fault: Report the PKRS state on fault ira.weiny
2020-11-06 23:29   ` ira.weiny
2020-11-06 23:29 ` [PATCH V3 08/10] x86/pks: Add PKS kernel API ira.weiny
2020-11-06 23:29   ` ira.weiny
2020-12-23 20:39   ` Randy Dunlap
2020-12-23 20:39     ` Randy Dunlap
2020-11-06 23:29 ` [PATCH V3 09/10] x86/pks: Enable Protection Keys Supervisor (PKS) ira.weiny
2020-11-06 23:29   ` ira.weiny
2020-11-06 23:29 ` [PATCH V3 10/10] x86/pks: Add PKS test code ira.weiny
2020-11-06 23:29   ` ira.weiny
2020-12-17 20:55   ` Dave Hansen
2020-12-17 20:55     ` Dave Hansen
2020-12-18  4:05     ` Ira Weiny
2020-12-18  4:05       ` Ira Weiny
2020-12-18 16:59       ` Dan Williams
2020-12-18 16:59         ` Dan Williams
2020-12-18 16:59         ` Dan Williams
2020-12-07 22:14 ` [PATCH V3 00/10] PKS: Add Protection Keys Supervisor (PKS) support V3 Ira Weiny
2020-12-07 22:14   ` Ira Weiny
2020-12-08 15:55   ` Thomas Gleixner
2020-12-08 15:55     ` Thomas Gleixner
2020-12-08 17:22     ` Ira Weiny
2020-12-08 17:22       ` Ira Weiny

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=7666e039-d005-a732-7ec9-35ac7f36ead3@intel.com \
    --to=dave.hansen@intel.com \
    --cc=akpm@linux-foundation.org \
    --cc=bp@alien8.de \
    --cc=dave.hansen@linux.intel.com \
    --cc=fenghua.yu@intel.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=ira.weiny@intel.com \
    --cc=linux-doc@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-kselftest@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=linux-nvdimm@lists.01.org \
    --cc=luto@kernel.org \
    --cc=mingo@redhat.com \
    --cc=peterz@infradead.org \
    --cc=tglx@linutronix.de \
    --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.