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From: Dave Hansen <dave.hansen@linux.intel.com>
To: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org, Dave Hansen <dave.hansen@linux.intel.com>,
	luto@kernel.org, torvalds@linux-foundation.org,
	keescook@google.com, hughd@google.com, jgross@suse.com,
	x86@kernel.org
Subject: [PATCH 0/3] Use global pages with PTI
Date: Thu, 15 Feb 2018 05:20:53 -0800	[thread overview]
Message-ID: <20180215132053.6C9B48C8@viggo.jf.intel.com> (raw)

The later verions of the KAISER pathces (pre-PTI) allowed the user/kernel
shared areas to be GLOBAL.  The thought was that this would reduce the
TLB overhead of keeping two copies of these mappings.

During the switch over to PTI, we seem to have lost our ability to have
GLOBAL mappings.  This adds them back.

Did we have some reason for leaving out global pages entirely?  We
_should_ have all the TLB flushing mechanics in place to handle these
already since all of our kernel mapping changes have to know how to
flush global pages regardless.

Cc: Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Kees Cook <keescook@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: x86@kernel.org

WARNING: multiple messages have this Message-ID (diff)
From: Dave Hansen <dave.hansen@linux.intel.com>
To: linux-kernel@vger.kernel.org
Cc: linux-mm@kvack.org, Dave Hansen <dave.hansen@linux.intel.com>,
	luto@kernel.org, torvalds@linux-foundation.org,
	keescook@google.com, hughd@google.com, jgross@suse.com,
	x86@kernel.org
Subject: [PATCH 0/3] Use global pages with PTI
Date: Thu, 15 Feb 2018 05:20:53 -0800	[thread overview]
Message-ID: <20180215132053.6C9B48C8@viggo.jf.intel.com> (raw)

The later verions of the KAISER pathces (pre-PTI) allowed the user/kernel
shared areas to be GLOBAL.  The thought was that this would reduce the
TLB overhead of keeping two copies of these mappings.

During the switch over to PTI, we seem to have lost our ability to have
GLOBAL mappings.  This adds them back.

Did we have some reason for leaving out global pages entirely?  We
_should_ have all the TLB flushing mechanics in place to handle these
already since all of our kernel mapping changes have to know how to
flush global pages regardless.

Cc: Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Kees Cook <keescook@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: x86@kernel.org

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             reply	other threads:[~2018-02-15 13:25 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-15 13:20 Dave Hansen [this message]
2018-02-15 13:20 ` [PATCH 0/3] Use global pages with PTI Dave Hansen
2018-02-15 13:20 ` [PATCH 1/3] x86/mm: factor out conditional pageattr PTE bit setting code Dave Hansen
2018-02-15 13:20   ` Dave Hansen
2018-02-15 13:20 ` [PATCH 2/3] x86/mm: introduce __PAGE_KERNEL_GLOBAL Dave Hansen
2018-02-15 13:20   ` Dave Hansen
2018-02-16 17:47   ` Nadav Amit
2018-02-16 17:47     ` Nadav Amit
2018-02-16 18:03     ` Dave Hansen
2018-02-16 18:03       ` Dave Hansen
2018-02-16 18:25       ` Nadav Amit
2018-02-16 18:25         ` Nadav Amit
2018-02-16 19:06         ` Dave Hansen
2018-02-16 19:06           ` Dave Hansen
2018-02-16 19:54           ` Nadav Amit
2018-02-16 19:54             ` Nadav Amit
2018-02-16 20:00             ` Dave Hansen
2018-02-16 20:00               ` Dave Hansen
2018-02-16 23:19         ` Dave Hansen
2018-02-16 23:19           ` Dave Hansen
2018-02-15 13:20 ` [PATCH 3/3] x86/pti: enable global pages for shared areas Dave Hansen
2018-02-15 13:20   ` Dave Hansen
2018-02-15 17:47 ` [PATCH 0/3] Use global pages with PTI Linus Torvalds
2018-02-15 17:47   ` Linus Torvalds
2018-02-15 18:13   ` Dave Hansen
2018-02-15 18:13     ` Dave Hansen
2018-02-15 23:55   ` Dave Hansen
2018-02-15 23:55     ` Dave Hansen
  -- strict thread matches above, loose matches on Subject: below --
2018-02-13 23:19 Dave Hansen

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