From: Wei Liu <wei.liu2@citrix.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Xen-devel <xen-devel@lists.xenproject.org>,
Wei Liu <wei.liu2@citrix.com>, Jan Beulich <JBeulich@suse.com>
Subject: Re: Make hvm_fep available to non-debug build as well?
Date: Wed, 15 Jun 2016 15:16:44 +0100 [thread overview]
Message-ID: <20160615141643.GD28116@citrix.com> (raw)
In-Reply-To: <575FEC29.902@citrix.com>
On Tue, Jun 14, 2016 at 12:36:09PM +0100, Andrew Cooper wrote:
> On 14/06/16 11:54, Jan Beulich wrote:
> >>>> On 14.06.16 at 12:47, <wei.liu2@citrix.com> wrote:
> >> Andrew and I had a short conversation on IRC about why hvm_fep is only
> >> available to debug build. Here is what he said:
> >>
> >> <andyhhp> liuw: because hvm_fep puts a very large attack surface back
> >> into the hypervisor
> >> <andyhhp> I intoduced it originally to make it easy to test the
> >> instruction emulator without requiring a race condition between
> >> two
> >> vcpus
> >> <andyhhp> so I guess paranoia is the underlying answer to your question
> >> <andyhhp> there is nothing wrong in principle with making available in
> >> non-debug builds
> >>
> >> I think I agree with him that in principle it should be possible to
> >> make hvm_fep available to non-debug build. Andrew also suggested a
> >> sync_console style warning, which I think makes sense.
> > Properly documented I'm not heavily opposed (but also not fully
> > convinced of this being a good idea).
>
> I have had one case where I needed to make FEP available in non-debug
> build, as a bug I was chasing had its repro symptoms disappeared in a
> debug build.
> (https://github.com/xenserver/xen-4.6.pg/commit/5826deab561dd92efaaeeb222c27184be257fad5
> for those who are interested)
>
> So long as it is obvious when it is enabled, I am a hesitant +1.
>
OK, I think I can start writing patch(es) to do that now.
Wei.
> ~Andrew
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prev parent reply other threads:[~2016-06-15 14:16 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-14 10:47 Make hvm_fep available to non-debug build as well? Wei Liu
2016-06-14 10:54 ` Jan Beulich
2016-06-14 11:36 ` Andrew Cooper
2016-06-15 14:16 ` Wei Liu [this message]
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