From: Steven Rostedt <rostedt@goodmis.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Linus Torvalds <torvalds@linux-foundation.org>,
"H. Peter Anvin" <hpa@zytor.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Jason Baron <jbaron@redhat.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
"H. Peter Anvin" <hpa@linux.intel.com>,
Paul Turner <pjt@google.com>
Subject: Re: [RFC][PATCH 3/3] x86: Add workaround to NMI iret woes
Date: Fri, 09 Dec 2011 10:25:29 -0500 [thread overview]
Message-ID: <1323444329.1937.22.camel@frodo> (raw)
In-Reply-To: <1323443432.16764.2.camel@twins>
On Fri, 2011-12-09 at 16:10 +0100, Peter Zijlstra wrote:
> KVM does NMIs, the write_idt thing is a paravirt call. Then again, a
> vcpu is a single thread of execution, there can only ever be 1 hypercall
> at the same time.
>
> The only thing that remains is if the hypercall interface is NMI-safe,
> what if the NMI comes in just as another context is also starting a
> hypercall. I really don't know enough about all that crap to know.
Hmm, well we can detect that we are a paravirt guest or not (that's the
nature of paravirt). We can keep the current methods around, an for
paravirt guests, it will fall back to the old stop_machine() method.
Heck guests have issues with latencies anyway.
For running on bare-metal, we can switch to this method.
-- Steve
next prev parent reply other threads:[~2011-12-09 15:25 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-08 19:30 [RFC][PATCH 0/3] x86: Find a way to allow breakpoints in NMIs Steven Rostedt
2011-12-08 19:30 ` [RFC][PATCH 1/3] x86: Do not schedule while still in NMI context Steven Rostedt
2011-12-08 19:30 ` [RFC][PATCH 2/3] x86: Document the NMI handler about not using paranoid_exit Steven Rostedt
2011-12-08 19:30 ` [RFC][PATCH 3/3] x86: Add workaround to NMI iret woes Steven Rostedt
2011-12-08 19:36 ` Steven Rostedt
2011-12-09 2:43 ` Steven Rostedt
2011-12-09 9:22 ` Peter Zijlstra
2011-12-09 15:00 ` Steven Rostedt
2011-12-09 15:10 ` Peter Zijlstra
2011-12-09 15:25 ` Steven Rostedt [this message]
2011-12-09 15:20 ` Steven Rostedt
2011-12-09 16:34 ` Steven Rostedt
2011-12-09 17:19 ` Steven Rostedt
2011-12-09 17:49 ` Borislav Petkov
2011-12-09 18:20 ` Steven Rostedt
2011-12-09 16:49 ` Jason Baron
2011-12-09 17:14 ` Steven Rostedt
2011-12-09 12:40 ` Mathieu Desnoyers
2011-12-09 13:02 ` Mathieu Desnoyers
2011-12-09 14:49 ` Steven Rostedt
2011-12-09 15:02 ` Mathieu Desnoyers
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