From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: x86@kernel.org, Song Liu <songliubraving@fb.com>,
Joerg Roedel <jroedel@suse.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Rik van Riel <riel@surriel.com>
Subject: [patch 0/2] x86/mm/pti: Robustness updates
Date: Wed, 28 Aug 2019 16:24:45 +0200 [thread overview]
Message-ID: <20190828142445.454151604@linutronix.de> (raw)
Following up on the discussions around the patch Song submitted to 'cure' a
iTLB related performance regression, I picked up Song's patch which makes
clone_page_tables() more robust by handling unaligned addresses proper and
added one which prevents calling into the PTI code when PTI is enabled
compile time, but disabled at runtime (command line or CPU not affected).
There is no point in calling into those PTI functions unconditionally. The
resulting page tables are the same before and after the change which makes
sense as the code clones the kernel page table into the secondary page
table space which is available but not used when PTI is boot time disabled.
But even if it does not do damage today, this could have nasty side effect
when the PTI code is changed, extended etc. later.
Thanks,
tglx
8<----------------
pti.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
next reply other threads:[~2019-08-28 14:31 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-28 14:24 Thomas Gleixner [this message]
2019-08-28 14:24 ` [patch 1/2] x86/mm/pti: Handle unaligned address gracefully in pti_clone_pagetable() Thomas Gleixner
2019-08-28 15:46 ` Dave Hansen
2019-08-28 15:51 ` Thomas Gleixner
2019-08-28 17:58 ` Song Liu
2019-08-28 20:05 ` Thomas Gleixner
2019-08-28 20:32 ` Song Liu
2019-08-28 22:31 ` [PATCH] x86/mm/cpa: Prevent large page split when ftrace flips RW on kernel text Thomas Gleixner
2019-08-28 23:03 ` Song Liu
2019-08-29 13:01 ` Peter Zijlstra
2019-08-29 18:55 ` [tip: x86/urgent] " tip-bot2 for Thomas Gleixner
2019-08-28 18:58 ` [patch 1/2] x86/mm/pti: Handle unaligned address gracefully in pti_clone_pagetable() Ingo Molnar
2019-08-28 19:45 ` Thomas Gleixner
2019-08-28 20:54 ` [patch V2 " Thomas Gleixner
2019-08-28 21:52 ` Thomas Gleixner
2019-08-28 21:54 ` [patch V3 " Thomas Gleixner
2019-08-28 23:22 ` Ingo Molnar
2019-08-29 19:02 ` [tip: x86/pti] " tip-bot2 for Song Liu
2019-08-30 10:24 ` [patch V3 1/2] " Joerg Roedel
2019-08-28 14:24 ` [patch 2/2] x86/mm/pti: Do not invoke PTI functions when PTI is disabled Thomas Gleixner
2019-08-28 15:47 ` Dave Hansen
2019-08-28 17:49 ` Song Liu
2019-08-28 19:00 ` Ingo Molnar
2019-08-29 19:02 ` [tip: x86/pti] " tip-bot2 for Thomas Gleixner
2019-08-30 10:25 ` [patch 2/2] " Joerg Roedel
2019-08-28 16:03 ` [patch 0/2] x86/mm/pti: Robustness updates Peter Zijlstra
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