Re: [PATCH] x86/fpu: CR0.TS should be set before trap into PV guest's #NM exception handle

[Sarah Newman <srn@prgmr.com>]

On 11/29/2013 01:42 AM, Jan Beulich wrote:
> I'm personally not eager to see something like this go in, most
> importantly because I think bugs should be fixed where they
> got introduced, not worked around elsewhere, and also
> because I think that a generally available workaround would
> lower the chances of the bug getting fixed properly.
If the proper bug fix was released first would that help?

> 
> Apart from that this workaround of yours would have very
> ugly behavior: If a guest later got updated to a fixed kernel,
> you'd have to alter its configuration along with booting into
> the new kernel (i.e. a simple reboot of the VM won't do), or
> else your new kernel would crash due to not clearing CR0.TS
> before trying to restore FPU context.
Assuming it predictably crashed, that would be easier to deal with than occasional silent memory
corruption.

I think something could be done with the on_reboot action, maybe a reload-restart?