Re: [PATCH v2 3/6] kvm: x86: Emulate split-lock access as a write

[Paolo Bonzini]

On 03/02/20 16:16, Xiaoyao Li wrote:
> A sane guest should never tigger emulation on a split-lock access, but
> it cannot prevent malicous guest from doing this. So just emulating the
> access as a write if it's a split-lock access to avoid malicous guest
> polluting the kernel log.

Saying that anything doing a split lock access is malicious makes little
sense.

Split lock detection is essentially a debugging feature, there's a
reason why the MSR is called "TEST_CTL".  So you don't want to make the
corresponding behavior wrong.  Just kill the guest with a
KVM_INTERNAL_ERROR userspace exit so people will notice quickly and
either disable the feature or see if they can fix the guest.

Paolo