From: Andrew Cooper <andrew.cooper3@citrix.com>
To: Jan Beulich <JBeulich@suse.com>
Cc: xen-devel@lists.xenproject.org, David Vrabel <david.vrabel@citrix.com>
Subject: Re: [PATCHv3 1/3] x86/fpu: improve check for XSAVE* not writing FIP/FDP fields
Date: Thu, 25 Feb 2016 15:07:15 +0000 [thread overview]
Message-ID: <56CF18A3.4040004@citrix.com> (raw)
In-Reply-To: <56CF1D7B02000078000D6367@prv-mh.provo.novell.com>
On 25/02/16 14:27, Jan Beulich wrote:
>>>> On 25.02.16 at 14:16, <andrew.cooper3@citrix.com> wrote:
>> No OS is plausibly going to hide non-IP information in FIP.
>>
>> If some theoretical OS does do something like that, there is always the
>> override available.
> But who says it needs to be an OS to do so? User mode code could
> as much (and would imo even be more likely to do so, compared to
> an OS).
Why does this matter? We *cannot* make a perfect heuristic in this case.
The new heuristic is wrong substantially less often than the old
heuristic, so is an improvement.
~Andrew
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next prev parent reply other threads:[~2016-02-25 15:07 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-25 10:58 [PATCHv3 0/3] x86: workaround inability to fully restore FPU state David Vrabel
2016-02-25 10:58 ` [PATCHv3 1/3] x86/fpu: improve check for XSAVE* not writing FIP/FDP fields David Vrabel
2016-02-25 11:32 ` Jan Beulich
2016-02-25 12:18 ` David Vrabel
2016-02-25 12:27 ` Jan Beulich
2016-02-25 12:49 ` David Vrabel
2016-02-25 13:16 ` Andrew Cooper
2016-02-25 14:27 ` Jan Beulich
2016-02-25 15:07 ` Andrew Cooper [this message]
2016-02-25 15:09 ` David Vrabel
2016-03-01 6:27 ` Tian, Kevin
2016-03-01 9:31 ` Jan Beulich
2016-02-25 10:58 ` [PATCHv3 2/3] x86/fpu: Add a per-domain field to set the width of FIP/FDP David Vrabel
2016-02-25 11:24 ` Jan Beulich
2016-02-25 11:38 ` David Vrabel
2016-02-25 11:55 ` Jan Beulich
2016-02-25 10:58 ` [PATCHv3 3/3] x86/hvm: add HVM_PARAM_X87_FIP_WIDTH David Vrabel
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