Re: [PATCH v2 5/6] kvm: x86: Emulate MSR IA32_CORE_CAPABILITIES

From: Peter Zijlstra
Date: Tue Feb 04 2020 - 04:37:39 EST


On Tue, Feb 04, 2020 at 05:19:26PM +0800, Xiaoyao Li wrote:

> > > + case MSR_IA32_CORE_CAPS:
> > > + if (!msr_info->host_initiated)
> >
> > Shouldn't @data be checked against kvm_get_core_capabilities()?
>
> Maybe it's for the case that userspace might have the ability to emulate SLD
> feature? And we usually let userspace set whatever it wants, e.g.,
> ARCH_CAPABILITIES.

If the 'sq_misc.split_lock' event is sufficiently accurate, I suppose
the host could use that to emulate the feature at the cost of one
counter used.