From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Jan Beulich <JBeulich@suse.com>, Wei Liu <wei.liu2@citrix.com>
Cc: Xen-devel <xen-devel@lists.xenproject.org>
Subject: Re: Make hvm_fep available to non-debug build as well?
Date: Tue, 14 Jun 2016 12:36:09 +0100 [thread overview]
Message-ID: <575FEC29.902@citrix.com> (raw)
In-Reply-To: <575FFE8A02000078000F4BCF@prv-mh.provo.novell.com>
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.
~Andrew
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next prev parent reply other threads:[~2016-06-14 11:36 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 [this message]
2016-06-15 14:16 ` Wei Liu
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