lkml.org 
[lkml]   [2019]   [Oct]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v9 09/17] x86/split_lock: Handle #AC exception for split lock
On Wed, Oct 16, 2019 at 04:08:14PM +0200, Paolo Bonzini wrote:
> SIGBUS (actually a new KVM_EXIT_INTERNAL_ERROR result from KVM_RUN is
> better, but that's the idea) is for when you're debugging guests.
> Global disable (or alternatively, disable SMT) is for production use.

Alternatively, for guests without split-lock #AC enabled, what if KVM were
to emulate the faulting instruction with split-lock detection temporarily
disabled?

The emulator can presumably handle all such lock instructions, and an
unhandled instruction would naturally exit to userspace.

The latency of VM-Enter+VM-Exit should be enough to guard against DoS from
a malicious guest. KVM could also artificially rate-limit a guest that is
generating copious amounts of split-lock #ACs.

\
 
 \ /
  Last update: 2019-10-16 17:42    [W:0.101 / U:14.844 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site