Re: [patch 0/2] x86: Prevent Split-Lock-Detection wreckage on VMX hypervisors

From: Nadav Amit
Date: Thu Apr 02 2020 - 10:47:42 EST


> On Apr 2, 2020, at 7:37 AM, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
>
> "Kenneth R. Crudup" <kenny@xxxxxxxxx> writes:
>
>> On Thu, 2 Apr 2020, Thomas Gleixner wrote:
>>
>>> As Peter and myself don't have access to a SLD enabled machine, the
>>> KVM/VMX part is untested. The module scan part works.
>>
>> I just applied both of these patches to my (Linus' tip) tree, and unfortunately
>> VMWare still hangs if split_lock_detect= is set to anything but "off".
>>
>> Was there anything else I'd needed to do?
>
> Hmm. Not really. Does dmesg show the warning when the VMWare module loads?
> Something like:
>
> x86/split lock detection: disabled due to VMLAUNCH in module: â.

I ran an objdump on VMware workstation and indeed I do not see a
VMLAUNCH/VMRESUME. I do see however VMXON which should also be good for
detecting hypervisors. I will try to understand why VMLAUNCH is not there.