[lkml]   [2022]   [Jul]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: Virt Call depth tracking mitigation
On Tue, Jul 19 2022 at 16:23, Andrew Cooper wrote:
> On 19/07/2022 15:13, Thomas Gleixner wrote:
>> Well, that makes the guest side "safe", but isn't a deep hypercall > 16
>> already underflowing in the hypervisor code before it returns to the
>> guest?
> Yeah, but that's the hypervisor's problem to deal with, in whatever
> manner it sees fit.
> And if the hypervisor is using IBeeRS then the first ret in guest
> context will underflow.

I have a look tomorrow.

>>> That said, after a return from the hypervisor, Linux has no idea what
>>> state the RSB is in, so the only safe course of action is to re-stuff.
>> Indeed.
>> Another proof for my claim that virt creates more problems than it
>> solves.
> So how did you like debugging the gsbase crash on native hardware. :)

First of all I said it's creating more problems than it solves, which
means it solves some problems.

But more important, I'm not a wimp.



 \ /
  Last update: 2022-07-19 23:17    [W:0.140 / U:0.120 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site