Re: [Xen-devel] [PATCH 2/2] libxl: fix osvm cpuid flag

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 28/06/17 17:14, Marek Marczykowski-Górecki wrote:
> On Wed, Jun 28, 2017 at 11:16:33AM +0100, Andrew Cooper wrote:
>> On 28/06/17 07:09, Jan Beulich wrote:
>>>>>> Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx> 06/28/17 
>>>>>> 3:09 AM >>>
>>>> It's bit 9 not 10 (which is ibs).
>>> Indeed, but shouldn't it rather be removed? We don't expose it from the
>>> hypervisor at all anymore:
>>>
>>> XEN_CPUFEATURE(OSVW,          3*32+ 9) /*   OS Visible Workaround */
>>>
>>> (note the absence of any marker character immediately inside the comment).
>> I don't believe we have ever actually offered OSVW to guests, despite
>> the pretence of being able to.  ISTR it was always clobbered before
>> being given to a guest.
>>
>> Having said that, we should be advertising OSVW.  It's entire purpose is
>> to tell the OS that there is something it can do to manually work round
>> a specific erratum.  OTOH, making this migrate safe is liable to be very
>> complicated...
> I don't have opinion on either approach here, but the current state is
> clearly wrong. You've got two versions of the patch, choose one ;)
>

I'd prefer this version of the patch, so it doesn't suddenly remove a
piece of libxl API, but it is up to Wei / Ian at the end of the day.

One option which was being discussed in the context of my CPUID (part 3)
work was to automatically this list of keywords.

~Andrew

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel