Linux-Fsdevel Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Peter Zijlstra <peterz@infradead.org>
To: 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>,
	Fenghua Yu <fenghua.yu@intel.com>,
	x86@kernel.org, Dave Hansen <dave.hansen@linux.intel.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Vishal Verma <vishal.l.verma@intel.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-nvdimm@lists.01.org, linux-fsdevel@vger.kernel.org,
	linux-mm@kvack.org, linux-kselftest@vger.kernel.org
Subject: Re: [RFC PATCH 04/15] x86/pks: Preserve the PKRS MSR on context switch
Date: Tue, 14 Jul 2020 10:27:01 +0200	[thread overview]
Message-ID: <20200714082701.GO10769@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20200714070220.3500839-5-ira.weiny@intel.com>

On Tue, Jul 14, 2020 at 12:02:09AM -0700, ira.weiny@intel.com wrote:
> From: Ira Weiny <ira.weiny@intel.com>
> 
> The PKRS MSR is defined as a per-core register.  This isolates memory
> access by CPU.  Unfortunately, the MSR is not preserved by XSAVE.
> Therefore, We must preserve the protections for individual tasks even if
> they are context switched out and placed on another cpu later.

This is a contradiction and utter trainwreck. We're not going to do more
per-core MSRs and pretend they make sense per-task.

  reply	other threads:[~2020-07-14  8:27 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-14  7:02 [RFC PATCH 00/15] PKS: Add Protection Keys Supervisor (PKS) support ira.weiny
2020-07-14  7:02 ` [RFC PATCH 01/15] x86/pkeys: Create pkeys_internal.h ira.weiny
2020-07-14  7:02 ` [RFC PATCH 02/15] x86/fpu: Refactor arch_set_user_pkey_access() for PKS support ira.weiny
2020-07-14  7:02 ` [RFC PATCH 03/15] x86/pks: Enable Protection Keys Supervisor (PKS) ira.weiny
2020-07-14  7:02 ` [RFC PATCH 04/15] x86/pks: Preserve the PKRS MSR on context switch ira.weiny
2020-07-14  8:27   ` Peter Zijlstra [this message]
2020-07-14 18:53     ` Ira Weiny
2020-07-14 18:56       ` Dave Hansen
2020-07-14 19:05       ` Peter Zijlstra
2020-07-14 19:09         ` Ira Weiny
2020-07-14  7:02 ` [RFC PATCH 05/15] x86/pks: Add PKS kernel API ira.weiny
2020-07-14  7:02 ` [RFC PATCH 06/15] x86/pks: Add a debugfs file for allocated PKS keys ira.weiny
2020-07-14  7:02 ` [RFC PATCH 07/15] Documentation/pkeys: Update documentation for kernel pkeys ira.weiny
2020-07-14  7:02 ` [RFC PATCH 08/15] x86/pks: Add PKS Test code ira.weiny
2020-07-14  7:02 ` [RFC PATCH 09/15] fs/dax: Remove unused size parameter ira.weiny
2020-07-14  7:02 ` [RFC PATCH 10/15] drivers/dax: Expand lock scope to cover the use of addresses ira.weiny
2020-07-14  7:02 ` [RFC PATCH 11/15] memremap: Add zone device access protection ira.weiny
2020-07-14  8:40   ` Peter Zijlstra
2020-07-14 19:10     ` Ira Weiny
2020-07-14 19:40       ` Peter Zijlstra
2020-07-14  7:02 ` [RFC PATCH 12/15] kmap: Add stray write protection for device pages ira.weiny
2020-07-14  8:44   ` Peter Zijlstra
2020-07-14 19:06     ` Ira Weiny
2020-07-14 19:29       ` Peter Zijlstra
2020-07-14 19:42         ` Dave Hansen
2020-07-14 19:49           ` Peter Zijlstra
2020-07-14 20:00           ` Ira Weiny
2020-07-14  7:02 ` [RFC PATCH 13/15] dax: Stray write protection for dax_direct_access() ira.weiny
2020-07-14  7:02 ` [RFC PATCH 14/15] nvdimm/pmem: Stray write protection for pmem->virt_addr ira.weiny
2020-07-14  7:02 ` [RFC PATCH 15/15] [dax|pmem]: Enable stray write protection 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=20200714082701.GO10769@hirez.programming.kicks-ass.net \
    --to=peterz@infradead.org \
    --cc=akpm@linux-foundation.org \
    --cc=bp@alien8.de \
    --cc=dan.j.williams@intel.com \
    --cc=dave.hansen@linux.intel.com \
    --cc=fenghua.yu@intel.com \
    --cc=ira.weiny@intel.com \
    --cc=linux-doc@vger.kernel.org \
    --cc=linux-fsdevel@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=tglx@linutronix.de \
    --cc=vishal.l.verma@intel.com \
    --cc=x86@kernel.org \
    --subject='Re: [RFC PATCH 04/15] x86/pks: Preserve the PKRS MSR on context switch' \
    /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

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).