Re: [PATCH v6 8/8] kvm: vmx: virtualize split lock detection

[Xiaoyao Li]

On 3/26/2020 10:55 PM, Thomas Gleixner wrote:
> Xiaoyao Li <xiaoyao.li@xxxxxxxxx> writes:
> > On 3/26/2020 7:10 PM, Thomas Gleixner wrote:
> > If the host has it disabled, !split_lock_detect_on() is true, it skips
> > following check due to ||
> >
> > if (!boot_cpu_has(X86_FEATURE_SPLIT_LOCK)) {
> > 	inject #AC back to guest
and 	return 1;

> That'd be a regular #AC, right?

Yes.

> > } else {
> > 	if (guest_alignment_check_enabled() || guest_sld_on())
> > 		inject #AC back to guest
and 		return 1;

> Here is clearly an else path missing.

the else path is fall through.

i.e. calling handle_user_split_lock().

If cannot handle, it falls through to report #AC to user space (QEMU)

> > }

If there is no problem with the above. So what's the problem of the 
original?