From: Brian Gerst <brgerst@gmail.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>,
LKML <linux-kernel@vger.kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>, Ingo Molnar <mingo@kernel.org>,
Borislav Petkov <bp@alien8.de>,
Denys Vlasenko <dvlasenk@redhat.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Rik van Riel <riel@redhat.com>,
Daniel Gruss <daniel.gruss@iaik.tugraz.at>,
Hugh Dickins <hughd@google.com>, Kees Cook <keescook@google.com>,
Linux-MM <linux-mm@kvack.org>,
michael.schwarz@iaik.tugraz.at, moritz.lipp@iaik.tugraz.at,
richard.fellner@student.tugraz.at
Subject: Re: [patch V2 1/5] x86/kaiser: Respect disabled CPU features
Date: Mon, 27 Nov 2017 07:31:37 -0500 [thread overview]
Message-ID: <CAMzpN2joDWU41SpNTu30pnOsZbdNcDMiCZ99HBy53SFVwvxMuw@mail.gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.20.1711271241100.1799@nanos>
On Mon, Nov 27, 2017 at 6:47 AM, Thomas Gleixner <tglx@linutronix.de> wrote:
> On Mon, 27 Nov 2017, Peter Zijlstra wrote:
>> On Mon, Nov 27, 2017 at 12:14:04AM +0100, Thomas Gleixner wrote:
>> > PAGE_NX and PAGE_GLOBAL might be not supported or disabled on the command
>> > line, but KAISER sets them unconditionally.
>>
>> So KAISER is x86_64 only, right? AFAIK there is no x86_64 without NX
>> support. So would it not make sense to mandate NX for KAISER?, that is
>> instead of making "noexec" + KAISER work, make "noexec" kill KAISER +
>> emit a warning.
>
> OTOH, disabling NX is a simple way to verify that DEBUG_WX works correctly
> also on the shadow maps.
>
> But surely we can drop the PAGE_GLOBAL thing, as all 64bit systems have it.
I seem to recall that some virtualized environments (maybe Xen?) don't
support global pages.
--
Brian Gerst
next prev parent reply other threads:[~2017-11-27 12:31 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-26 23:14 [patch V2 0/5] x86/kaiser: Boot time disabling and debug support Thomas Gleixner
2017-11-26 23:14 ` [patch V2 1/5] x86/kaiser: Respect disabled CPU features Thomas Gleixner
2017-11-27 9:57 ` Peter Zijlstra
2017-11-27 11:47 ` Thomas Gleixner
2017-11-27 12:31 ` Brian Gerst [this message]
2017-11-27 13:18 ` Thomas Gleixner
2017-11-27 18:11 ` Dave Hansen
2017-11-27 18:37 ` Kees Cook
2017-11-26 23:14 ` [patch V2 2/5] x86/kaiser: Simplify disabling of global pages Thomas Gleixner
2017-11-27 11:49 ` Thomas Gleixner
2017-11-27 18:15 ` Dave Hansen
2017-11-27 20:28 ` Thomas Gleixner
2017-11-26 23:14 ` [patch V2 3/5] x86/dump_pagetables: Check KAISER shadow page table for WX pages Thomas Gleixner
2017-11-27 18:17 ` Dave Hansen
2017-11-26 23:14 ` [patch V2 4/5] x86/mm/debug_pagetables: Allow dumping current pagetables Thomas Gleixner
2017-11-27 9:41 ` Peter Zijlstra
2017-11-27 10:06 ` [PATCH] vfs: Add PERM_* symbolic helpers for common file mode/permissions Ingo Molnar
2017-11-27 19:21 ` Linus Torvalds
2017-11-28 10:54 ` Ingo Molnar
2017-11-28 11:12 ` Ingo Molnar
2017-11-29 8:52 ` Michael Ellerman
2017-11-27 18:18 ` [patch V2 4/5] x86/mm/debug_pagetables: Allow dumping current pagetables Dave Hansen
2017-11-26 23:14 ` [patch V2 5/5] x86/kaiser: Add boottime disable switch Thomas Gleixner
2017-11-27 9:48 ` Peter Zijlstra
2017-11-27 10:22 ` Peter Zijlstra
2017-11-27 11:50 ` Thomas Gleixner
2017-11-27 12:49 ` Peter Zijlstra
2017-11-27 21:43 ` Peter Zijlstra
2017-11-27 18:22 ` Dave Hansen
2017-11-27 19:00 ` Thomas Gleixner
2017-11-27 19:18 ` Josh Poimboeuf
2017-11-27 20:47 ` Thomas Gleixner
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