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From: Dave Hansen <dave.hansen@linux.intel.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	richard.fellner@student.tugraz.at, moritz.lipp@iaik.tugraz.at,
	daniel.gruss@iaik.tugraz.at, michael.schwarz@iaik.tugraz.at,
	luto@kernel.org, torvalds@linux-foundation.org,
	keescook@google.com, hughd@google.com, x86@kernel.org
Subject: Re: [PATCH 08/30] x86, kaiser: unmap kernel from userspace page tables (core patch)
Date: Wed, 22 Nov 2017 14:54:29 -0800	[thread overview]
Message-ID: <63daa6c0-76de-ee67-6a77-fef601a22943@linux.intel.com> (raw)
In-Reply-To: <alpine.DEB.2.20.1711201518490.1734@nanos>

On 11/20/2017 09:21 AM, Thomas Gleixner wrote:
>> +page tables are switched to the full "kernel" copy.  When the
>> +system switches back to user mode, the user/shadow copy is used.
>> +
>> +The minimalistic kernel portion of the user page tables try to
>> +map only what is needed to enter/exit the kernel such as the
>> +entry/exit functions themselves and the interrupt descriptor
>> +table (IDT).
> s/try to//

Actually, they do _aspire_ "to map only what is needed".  But, there
*is* some non-necessary cruft (like the first C function in an
interrupt).  So, removing this language actually makes the description
less precise.

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  parent reply	other threads:[~2017-11-22 22:54 UTC|newest]

Thread overview: 77+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-10 19:30 [PATCH 00/30] [v3] KAISER: unmap most of the kernel from userspace page tables Dave Hansen
2017-11-10 19:31 ` [PATCH 01/30] x86, mm: do not set _PAGE_USER for init_mm " Dave Hansen
2017-11-10 19:31 ` [PATCH 02/30] x86, tlb: Make CR4-based TLB flushes more robust Dave Hansen
2017-11-10 19:31 ` [PATCH 03/30] x86/mm: Document X86_CR4_PGE toggling behavior Dave Hansen
2017-11-10 19:31 ` [PATCH 04/30] x86, kaiser: disable global pages by default with KAISER Dave Hansen
2017-11-14 19:38   ` Rik van Riel
2017-11-26 14:48     ` Ingo Molnar
2017-11-27 11:37       ` Thomas Gleixner
2017-11-27 13:20         ` [PATCH v2] x86/mm/kaiser: Disable " Ingo Molnar
2017-11-27 13:23           ` Thomas Gleixner
2017-11-27 13:27             ` Ingo Molnar
2017-11-10 19:31 ` [PATCH 05/30] x86, kaiser: prepare assembly for entry/exit CR3 switching Dave Hansen
2017-11-20 12:17   ` Thomas Gleixner
2017-11-10 19:31 ` [PATCH 06/30] x86, kaiser: introduce user-mapped per-cpu areas Dave Hansen
2017-11-10 19:31 ` [PATCH 07/30] x86, kaiser: mark per-cpu data structures required for entry/exit Dave Hansen
2017-11-10 19:31 ` [PATCH 08/30] x86, kaiser: unmap kernel from userspace page tables (core patch) Dave Hansen
2017-11-20 17:21   ` Thomas Gleixner
2017-11-22 22:45     ` Dave Hansen
2017-11-22 22:50     ` Dave Hansen
2017-11-22 22:54     ` Dave Hansen [this message]
2017-11-22 23:11     ` Dave Hansen
2017-11-10 19:31 ` [PATCH 09/30] x86, kaiser: only populate shadow page tables for userspace Dave Hansen
2017-11-20 20:12   ` Thomas Gleixner
2017-11-21  7:05     ` Ingo Molnar
2017-11-21 22:09     ` Dave Hansen
2017-11-22  3:44       ` Andy Lutomirski
2017-11-22 23:30         ` Dave Hansen
2017-11-10 19:31 ` [PATCH 10/30] x86, kaiser: allow NX poison to be set in p4d/pgd Dave Hansen
2017-11-10 19:31 ` [PATCH 11/30] x86, kaiser: make sure static PGDs are 8k in size Dave Hansen
2017-11-10 19:31 ` [PATCH 12/30] x86, kaiser: map GDT into user page tables Dave Hansen
2017-11-20 20:22   ` Thomas Gleixner
2017-11-20 20:46     ` Andy Lutomirski
2017-11-20 20:55       ` Thomas Gleixner
2017-11-21 21:19       ` Dave Hansen
2017-11-21 22:46         ` Andy Lutomirski
2017-11-21 23:17           ` Dave Hansen
2017-11-21 23:32             ` Andy Lutomirski
2017-11-21 23:42               ` Dave Hansen
2017-11-22  0:17                 ` Andy Lutomirski
2017-11-22  0:37                   ` Dave Hansen
2017-11-21 22:12     ` Dave Hansen
2017-11-10 19:31 ` [PATCH 13/30] x86, kaiser: map dynamically-allocated LDTs Dave Hansen
2017-11-10 19:31 ` [PATCH 14/30] x86, kaiser: map espfix structures Dave Hansen
2017-11-10 19:31 ` [PATCH 15/30] x86, kaiser: map entry stack variables Dave Hansen
2017-11-10 19:31 ` [PATCH 16/30] x86, kaiser: map trace interrupt entry Dave Hansen
2017-11-10 19:31 ` [PATCH 17/30] x86, kaiser: map debug IDT tables Dave Hansen
2017-11-20 20:40   ` Thomas Gleixner
2017-11-21 22:16     ` Dave Hansen
2017-11-20 20:44   ` Andy Lutomirski
2017-11-20 20:54     ` Thomas Gleixner
2017-11-10 19:31 ` [PATCH 18/30] x86, kaiser: map virtually-addressed performance monitoring buffers Dave Hansen
2017-11-14 18:20   ` Peter Zijlstra
2017-11-14 18:28     ` Dave Hansen
2017-11-14 19:10       ` Hugh Dickins
2017-11-14 19:24         ` Andy Lutomirski
2017-11-15  9:41         ` Peter Zijlstra
2017-11-10 19:31 ` [PATCH 19/30] x86, mm: Move CR3 construction functions Dave Hansen
2017-11-10 19:31 ` [PATCH 20/30] x86, mm: remove hard-coded ASID limit checks Dave Hansen
2017-11-20 20:47   ` Thomas Gleixner
2017-11-10 19:31 ` [PATCH 21/30] x86, mm: put mmu-to-h/w ASID translation in one place Dave Hansen
2017-11-10 22:03   ` Andy Lutomirski
2017-11-10 22:09     ` Dave Hansen
2017-11-10 22:10       ` Andy Lutomirski
2017-11-10 19:31 ` [PATCH 22/30] x86, pcid, kaiser: allow flushing for future ASID switches Dave Hansen
2017-11-10 19:31 ` [PATCH 23/30] x86, kaiser: use PCID feature to make user and kernel switches faster Dave Hansen
2017-11-16 19:19   ` Andrea Arcangeli
2017-11-16 19:25     ` Dave Hansen
2017-11-10 19:31 ` [PATCH 24/30] x86, kaiser: disable native VSYSCALL Dave Hansen
2017-11-10 19:31 ` [PATCH 25/30] x86, kaiser: add debugfs file to turn KAISER on/off at runtime Dave Hansen
2017-11-10 19:31 ` [PATCH 26/30] x86, kaiser: add a function to check for KAISER being enabled Dave Hansen
2017-11-10 19:31 ` [PATCH 27/30] x86, kaiser: un-poison PGDs at runtime Dave Hansen
2017-11-10 19:31 ` [PATCH 28/30] x86, kaiser: allow KAISER to be enabled/disabled " Dave Hansen
2017-11-10 19:32 ` [PATCH 29/30] x86, kaiser: add Kconfig Dave Hansen
2017-11-10 19:32 ` [PATCH 30/30] x86, kaiser, xen: Dynamically disable KAISER when running under Xen PV Dave Hansen
2017-11-20 16:02 ` [PATCH 00/30] [v3] KAISER: unmap most of the kernel from userspace page tables Juerg Haefliger
  -- strict thread matches above, loose matches on Subject: below --
2017-11-08 19:46 [PATCH 00/30] [v2] " Dave Hansen
2017-11-08 19:47 ` [PATCH 08/30] x86, kaiser: unmap kernel from userspace page tables (core patch) Dave Hansen
2017-11-10 12:57   ` Ingo Molnar

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