On 12/13/2016 02:24 PM, Andrew Cooper wrote:
Hello,
All of this came about while reviewing some of Jans improvements to the
x86 instruction emulator.
It turns out that the XSA-156 / CVE-2015-8104 fix, c/s bd2239d9
"x86/HVM: always intercept #AC and #DB", introduced an awkward bug on
Intel har
On 14/12/16 07:29, Tian, Kevin wrote:
>> From: Andrew Cooper [mailto:andrew.coop...@citrix.com]
>> Sent: Wednesday, December 14, 2016 3:25 AM
>>
>> Hello,
>>
>> All of this came about while reviewing some of Jans improvements to the
>> x86 instruction emulator.
>>
>> It turns out that the XSA-156 /
>>> On 13.12.16 at 20:24, wrote:
> Experimentally, on both Intel and AMD hardware, the mov_ss shadow
> inhibits #DB and the VMexit caused by its interception, whereas the sti
> shadow doesn't inhibit #DB. Therefore, my planned fix for VT-x is to
> unconditionally clobber the sti shadow if we inte
>>> On 14.12.16 at 08:29, wrote:
>> From: Andrew Cooper [mailto:andrew.coop...@citrix.com]
>> Sent: Wednesday, December 14, 2016 3:25 AM
>> Executing a sti while singlestepping is active currently causes a
>> VMEntry failure, because the #DB is still intercepted, but on re-entry,
>> the sti inter
> From: Andrew Cooper [mailto:andrew.coop...@citrix.com]
> Sent: Wednesday, December 14, 2016 3:25 AM
>
> Hello,
>
> All of this came about while reviewing some of Jans improvements to the
> x86 instruction emulator.
>
> It turns out that the XSA-156 / CVE-2015-8104 fix, c/s bd2239d9
> "x86/HVM:
Hello,
All of this came about while reviewing some of Jans improvements to the
x86 instruction emulator.
It turns out that the XSA-156 / CVE-2015-8104 fix, c/s bd2239d9
"x86/HVM: always intercept #AC and #DB", introduced an awkward bug on
Intel hardware.
Executing a sti while singlestepping is a
