Re: [PATCH v2 0/9] arm64: KVM: debug infrastructure support

Christoffer Dall
2014-05-25T15:34:26Z

On Tue, May 20, 2014 at 05:55:36PM +0100, Marc Zyngier wrote:
> This patch series adds debug support, a key feature missing from the
> KVM/arm64 port.
>
> The main idea is to keep track of whether the debug registers are
> "dirty" (changed by the guest) or not. In this case, perform the usual
> save/restore dance, for one run only. It means we only have a penalty
> if a guest is actively using the debug registers.
>
> The amount of registers is properly frightening, but CPUs actually
> only implement a subset of them. Also, there is a number of registers
> we don't bother emulating (things having to do with external debug and
> OSlock).

What is the rationale about not having to deal with external debug and
OSlock?

-Christoffer