From: Peter Zijlstra <peterz@infradead.org>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Andy Lutomirski <luto@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
LKML <linux-kernel@vger.kernel.org>, X86 ML <x86@kernel.org>
Subject: Re: [RFC][PATCH 0/4] x86/entry: disallow #DB more
Date: Mon, 25 May 2020 20:08:34 +0200 [thread overview]
Message-ID: <20200525180834.GF317569@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <2E6DBDE0-FEEA-467F-A380-4ED736B6C912@amacapital.net>
On Mon, May 25, 2020 at 10:19:08AM -0700, Andy Lutomirski wrote:
> How about adding it to cpu_tlbstate? A lot of NMIs are going to read
> that anyway to check CR3.
That might work I suppose; we're really pushing the name of it though.
Also, that's PTI specific IIRC, and we're getting to the point where a
significant number of CPUs no longer need that, right?
> And blaming KVM is a bit misplaced. This isn’t KVM’s fault — it’s
> Intel’s. VT-x has two modes: DR access exits and DR access doesn’t
> exit. There’s no shadow mode.
It's virt, I can't be arsed to care, whoever misdesigned it.
We already have debugreg pvops, they can do shadow there.
prev parent reply other threads:[~2020-05-25 18:08 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-22 20:47 [RFC][PATCH 0/4] x86/entry: disallow #DB more Peter Zijlstra
2020-05-22 20:47 ` [RFC][PATCH 1/4] x86/entry: Introduce local_db_{rave,restore}() Peter Zijlstra
2020-05-22 20:47 ` [RFC][PATCH 2/4] x86/entry, nmi: Disable #DB Peter Zijlstra
2020-05-22 20:47 ` [RFC][PATCH 3/4] x86/entry: Remove debug IST frobbing Peter Zijlstra
2020-05-22 20:47 ` [RFC][PATCH 4/4] x86/entry, mce: Disallow #DB during #MC Peter Zijlstra
2020-05-22 22:13 ` [RFC][PATCH 0/4] x86/entry: disallow #DB more Andy Lutomirski
2020-05-22 22:20 ` Sean Christopherson
2020-05-22 22:43 ` Andy Lutomirski
2020-05-23 12:59 ` Peter Zijlstra
2020-05-23 21:32 ` Peter Zijlstra
2020-05-25 10:02 ` Rasmus Villemoes
2020-05-25 10:40 ` Peter Zijlstra
2020-05-25 11:01 ` Peter Zijlstra
2020-05-25 17:19 ` Andy Lutomirski
2020-05-25 18:08 ` Peter Zijlstra [this message]
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