[PATCH V11 00/17] riscv: Add Native/Paravirt qspinlock support

[Guo Ren]

On Tue, Sep 12, 2023 at 4:08 PM Conor Dooley <conor.dooley at microchip.com> wrote:
>
> On Tue, Sep 12, 2023 at 09:33:57AM +0800, Guo Ren wrote:
> > On Mon, Sep 11, 2023 at 8:53 PM Conor Dooley <conor.dooley at microchip.com> wrote:
>
> > > I added the new "riscv,isa-extensions" property in part to make
> > > communicating vendor extensions like this easier. Please try to use
> > > that. "qspinlock" is software configuration though, the vendor extension
> > > should focus on the guarantee of strong forward progress, since that is
> > > the non-standard aspect of your IP.
> >
> > The qspinlock contains three paths:
> >  - Native qspinlock, this is your strong forward progress.
> >  - virt_spin_lock, for KVM guest when paravirt qspinlock disabled.
> >    https://lore.kernel.org/linux-riscv/20230910082911.3378782-9-guoren@kernel.org/
> >  - paravirt qspinlock, for KVM guest
> >
> > So, we need a software configuration here, "riscv,isa-extensions" is
> > all about vendor extension.
>
> Ah right, yes it would only be able to be used to determine whether or
> not the platform is capable of supporting these spinlocks, not whether or
> not the kernel is a guest. I think I misinterpreted that snippet you posted,
> thinking you were trying to disable your new spinlock for KVM, sorry.
> On that note though, what about other sorts of guests? Will non-KVM
> guests not also want to use this virt spinlock?
I only put KVM guests here, and I can't answer other hypervisor that
is another topic.

>
> Thanks,
> Conor.



-- 
Best Regards
 Guo Ren