From: Thomas Gleixner <tglx@linutronix.de>
To: Andy Lutomirski <luto@kernel.org>
Cc: X86 ML <x86@kernel.org>, Borislav Petkov <bpetkov@suse.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Brian Gerst <brgerst@gmail.com>,
Dave Hansen <dave.hansen@intel.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Josh Poimboeuf <jpoimboe@redhat.com>
Subject: Re: [PATCH 2/2] x86/kpti: Reference all cpu_entry_area pagetables in the usermode tables
Date: Sat, 2 Dec 2017 11:38:09 +0100 (CET) [thread overview]
Message-ID: <alpine.DEB.2.20.1712021136290.2199@nanos> (raw)
In-Reply-To: <6b7540535dccc043cee1a2d2e399e1eebf9eb332.1512195450.git.luto@kernel.org>
On Fri, 1 Dec 2017, Andy Lutomirski wrote:
> We were manually configuring cpu_entry_area in the usermode tables.
> This was error-prone and wasted memory. (Not much memory, but
> still.) Instead, just reference the same pagetables.
>
> This avoids needing to keep the KPTI code and the normal
> cpu_entry_area code in sync, since the KPTI code no longer cares
> what's in cpu_entry_area.
>
> [This does *not* work on the current KPTI series. It requires that
> all the kernelmode cpu_entry_tables are pre-allocated. That
> happens in the series as I submitted it, but tglx changed it for
> reasons that I haven't figured out.]
As I said it crashed and burned for yet unknown reasons. I'll dig into
that.
Thanks,
tglx
prev parent reply other threads:[~2017-12-02 10:38 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-02 6:20 [PATCH 0/2] KPTI: get rid of cpu_entry_area mapping duplication Andy Lutomirski
2017-12-02 6:20 ` [PATCH 1/2] Undo the split of setup_cpu_entry_area Andy Lutomirski
2017-12-02 10:34 ` Thomas Gleixner
2017-12-02 10:47 ` Thomas Gleixner
2017-12-02 13:34 ` Andy Lutomirski
2017-12-02 14:20 ` Thomas Gleixner
2017-12-02 6:20 ` [PATCH 2/2] x86/kpti: Reference all cpu_entry_area pagetables in the usermode tables Andy Lutomirski
2017-12-02 10:38 ` Thomas Gleixner [this message]
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