lkml.org 
[lkml]   [2020]   [Mar]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v5 3/9] x86/split_lock: Re-define the kernel param option for split_lock_detect
On Tue, Mar 24, 2020 at 11:40:18AM +0100, Thomas Gleixner wrote:
> Xiaoyao Li <xiaoyao.li@intel.com> writes:
> > On 3/24/2020 1:10 AM, Thomas Gleixner wrote:
> >> Xiaoyao Li <xiaoyao.li@intel.com> writes:
> >>
> >>> Change sld_off to sld_disable, which means disabling feature split lock
> >>> detection and it cannot be used in kernel nor can kvm expose it guest.
> >>> Of course, the X86_FEATURE_SPLIT_LOCK_DETECT is not set.
> >>>
> >>> Add a new optioin sld_kvm_only, which means kernel turns split lock
> >>> detection off, but kvm can expose it to guest.
> >>
> >> What's the point of this? If the host is not clean, then you better fix
> >> the host first before trying to expose it to guests.
> >
> > It's not about whether or not host is clean. It's for the cases that
> > users just don't want it enabled on host, to not break the applications
> > or drivers that do have split lock issue.
>
> It's very much about whether the host is split lock clean.
>
> If your host kernel is not, then this wants to be fixed first. If your
> host application is broken, then either fix it or use "warn".

The "kvm only" option was my suggestion. The thought was to provide a way
for users to leverage KVM to debug/test kernels without having to have a
known good kernel and/or to minimize the risk of crashing their physical
system. E.g. debug a misbehaving driver by assigning its associated device
to a guest.

\
 
 \ /
  Last update: 2020-03-24 19:02    [W:0.119 / U:0.308 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site