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From: Thomas Gleixner <tglx@linutronix.de>
To: Stephen Hemminger <stephen@networkplumber.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Stephen Hemminger <sthemmin@microsoft.com>,
	Simon Xiao <sixiao@microsoft.com>,
	KY Srinivasan <kys@microsoft.com>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Denys Vlasenko <dvlasenk@redhat.com>,
	Brian Gerst <brgerst@gmail.com>, Borislav Petkov <bp@alien8.de>,
	Andy Lutomirski <luto@kernel.org>
Subject: Re: [PATCH] x86/idt: Unbreak MS HyperV hypercall vector install
Date: Fri, 8 Sep 2017 19:09:18 +0200 (CEST)	[thread overview]
Message-ID: <alpine.DEB.2.20.1709081907460.1888@nanos> (raw)
In-Reply-To: <20170908095726.35b82463@xeon-e3>

On Fri, 8 Sep 2017, Stephen Hemminger wrote:
> On Fri, 8 Sep 2017 01:19:52 -0700
> "Thomas Gleixner" <tglx@linutronix.de> wrote:
> 
> > The rework of the IDT setup changed the way how unused system gates are
> > accounted. At the end of the gate initialization all unused gates in the
> > system vector area are set to the spurios handler and marked as used for
> > consistency reasons.
> > 
> > Marking them as used breaks MS HyperV because it installs its hypercall
> > vector after that point and the installation is guarded by the bit in the
> > used_vectors map. So the hyperv vector stays directed to the spurious
> > interrupt handler.
> > 
> > Leave them marked as unused again and unbreak HyperV that way.
> > 
> > Fixes: dc20b2d52653 ("x86/idt: Move interrupt gate initialization to IDT
> > code")
> > Reported-by: Stephen Hemminger <sthemmin@microsoft.com>
> > Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> 
> This fixes it, thanks.
> 
> Tested-by: Stephen Hemminger <sthemmin@microsoft.com>

What's the reason that the vector is not set up early in the boot process?

Thanks,

	tglx
	

  reply	other threads:[~2017-09-08 17:09 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-08  8:19 Thomas Gleixner
2017-09-08 16:12 ` Haiyang Zhang
2017-09-08 16:57 ` Stephen Hemminger
2017-09-08 17:09   ` Thomas Gleixner [this message]
2017-09-08 17:15     ` KY Srinivasan

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