From: Dave Hansen <dave.hansen@linux.intel.com>
To: Jiri Kosina <jikos@kernel.org>
Cc: Yisheng Xie <xieyisheng1@huawei.com>,
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, Linus Torvalds <torvalds@linux-foundation.org>,
keescook@google.com, hughd@google.com, x86@kernel.org,
Andrea Arcangeli <aarcange@redhat.com>
Subject: Re: [PATCH 05/23] x86, kaiser: unmap kernel from userspace page tables (core patch)
Date: Fri, 5 Jan 2018 13:07:03 -0800 [thread overview]
Message-ID: <868196c9-52ed-4270-968f-97b7a6784f61@linux.intel.com> (raw)
In-Reply-To: <nycvar.YFH.7.76.1801052014050.11852@cbobk.fhfr.pm>
On 01/05/2018 11:17 AM, Jiri Kosina wrote:
> On Fri, 5 Jan 2018, Dave Hansen wrote:
>
>>> --- a/arch/x86/platform/efi/efi_64.c
>>> +++ b/arch/x86/platform/efi/efi_64.c
>>> @@ -95,6 +95,12 @@ pgd_t * __init efi_call_phys_prolog(void
>>> save_pgd[pgd] = *pgd_offset_k(pgd * PGDIR_SIZE);
>>> vaddress = (unsigned long)__va(pgd * PGDIR_SIZE);
>>> set_pgd(pgd_offset_k(pgd * PGDIR_SIZE), *pgd_offset_k(vaddress));
>>> + /*
>>> + * pgprot API doesn't clear it for PGD
>>> + *
>>> + * Will be brought back automatically in _epilog()
>>> + */
>>> + pgd_offset_k(pgd * PGDIR_SIZE)->pgd &= ~_PAGE_NX;
>>> }
>>> __flush_tlb_all();
>>
>> Wait a sec... Where does the _PAGE_USER come from? Shouldn't we see
>> the &init_mm in there and *not* set _PAGE_USER?
>
> That's because pgd_populate() uses _PAGE_TABLE and not _KERNPG_TABLE for
> reasons that are behind me.
>
> I did put this on my TODO list, but for later.
>
> (and yes, I tried clearing _PAGE_USER from init_mm's PGD, and no obvious
> breakages appeared, but I wanted to give it more thought later).
Feel free to add my Ack on this. I'd personally much rather muck with
random relatively unused bits of the efi code than touch the core PGD code.
We need to go look at it again in the 4.16 timeframe, probably.
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next prev parent reply other threads:[~2018-01-05 21:07 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-23 0:34 [PATCH 00/23] [v4] KAISER: unmap most of the kernel from userspace page tables Dave Hansen
2017-11-23 0:34 ` [PATCH 01/23] x86, kaiser: disable global pages by default with KAISER Dave Hansen
2017-11-23 0:34 ` [PATCH 02/23] x86, kaiser: prepare assembly for entry/exit CR3 switching Dave Hansen
2017-11-23 0:34 ` [PATCH 03/23] x86, kaiser: introduce user-mapped per-cpu areas Dave Hansen
2017-11-23 0:34 ` [PATCH 04/23] x86, kaiser: mark per-cpu data structures required for entry/exit Dave Hansen
2017-11-23 0:34 ` [PATCH 05/23] x86, kaiser: unmap kernel from userspace page tables (core patch) Dave Hansen
2017-11-23 4:07 ` Andy Lutomirski
2017-11-26 16:10 ` Andy Lutomirski
2017-11-26 16:24 ` Dave Hansen
2017-11-26 16:29 ` Andy Lutomirski
2018-01-05 4:16 ` Yisheng Xie
2018-01-05 5:18 ` Dave Hansen
2018-01-05 6:16 ` Yisheng Xie
2018-01-05 6:29 ` Dave Hansen
2018-01-05 11:49 ` Andrea Arcangeli
2018-01-05 18:19 ` Jiri Kosina
2018-01-05 19:00 ` Jiri Kosina
2018-01-05 19:03 ` Dave Hansen
2018-01-05 19:17 ` Jiri Kosina
2018-01-05 19:18 ` Jiri Kosina
2018-01-05 19:55 ` Andrea Arcangeli
2018-01-05 21:07 ` Dave Hansen [this message]
2018-01-05 21:14 ` Jiri Kosina
2018-01-05 21:29 ` Andy Lutomirski
2018-01-05 22:48 ` Hugh Dickins
2018-01-06 4:54 ` Hanjun Guo
2018-01-06 6:06 ` Dave Hansen
2018-01-06 6:28 ` Hanjun Guo
2018-01-06 6:53 ` Hanjun Guo
2018-01-06 7:55 ` Dave Hansen
2018-01-06 8:42 ` Hanjun Guo
2018-01-06 7:51 ` Dave Hansen
2018-01-06 17:22 ` Andrea Arcangeli
2017-11-23 0:34 ` [PATCH 06/23] x86, kaiser: allow NX poison to be set in p4d/pgd Dave Hansen
2017-11-23 0:34 ` [PATCH 07/23] x86, kaiser: make sure static PGDs are 8k in size Dave Hansen
2017-11-23 0:34 ` [PATCH 08/23] x86, kaiser: map cpu entry area Dave Hansen
2017-11-23 0:34 ` [PATCH 09/23] x86, kaiser: map dynamically-allocated LDTs Dave Hansen
2017-11-23 19:42 ` Eric Biggers
2017-11-23 20:12 ` Andy Lutomirski
2017-11-23 0:34 ` [PATCH 10/23] x86, kaiser: map espfix structures Dave Hansen
2017-11-23 0:34 ` [PATCH 11/23] x86, kaiser: map entry stack variables Dave Hansen
2017-11-23 3:31 ` Andy Lutomirski
2017-11-23 15:37 ` Dave Hansen
2017-11-23 15:55 ` Andy Lutomirski
2017-11-23 0:35 ` [PATCH 12/23] x86, kaiser: map virtually-addressed performance monitoring buffers Dave Hansen
2017-11-23 0:35 ` [PATCH 13/23] x86, mm: Move CR3 construction functions Dave Hansen
2017-11-23 0:35 ` [PATCH 14/23] x86, mm: remove hard-coded ASID limit checks Dave Hansen
2017-11-23 0:35 ` [PATCH 15/23] x86, mm: put mmu-to-h/w ASID translation in one place Dave Hansen
2017-11-23 0:35 ` [PATCH 16/23] x86, pcid, kaiser: allow flushing for future ASID switches Dave Hansen
2017-11-23 0:35 ` [PATCH 17/23] x86, kaiser: use PCID feature to make user and kernel switches faster Dave Hansen
2017-11-23 0:35 ` [PATCH 18/23] x86, kaiser: disable native VSYSCALL Dave Hansen
2017-11-23 0:35 ` [PATCH 19/23] x86, kaiser: add debugfs file to turn KAISER on/off at runtime Dave Hansen
2017-11-23 0:35 ` [PATCH 20/23] x86, kaiser: add a function to check for KAISER being enabled Dave Hansen
2017-11-25 1:23 ` Eduardo Valentin
2017-11-23 0:35 ` [PATCH 21/23] x86, kaiser: un-poison PGDs at runtime Dave Hansen
2017-11-25 1:17 ` Eduardo Valentin
2017-11-23 0:35 ` [PATCH 22/23] x86, kaiser: allow KAISER to be enabled/disabled " Dave Hansen
2017-11-23 0:35 ` [PATCH 23/23] x86, kaiser: add Kconfig Dave Hansen
2017-11-23 7:23 ` [PATCH 00/23] [v4] KAISER: unmap most of the kernel from userspace page tables Ingo Molnar
2017-11-23 7:27 ` Ingo Molnar
2017-11-23 7:32 ` Ingo Molnar
2017-11-23 15:02 ` Dave Hansen
2017-11-23 16:20 ` Dave Hansen
2017-11-24 6:35 ` Ingo Molnar
2017-11-24 6:41 ` Dave Hansen
2017-11-24 7:33 ` Ingo Molnar
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