Re: [PATCH v5 00/20] KVM RISC-V Support

Anup Patel
2019-08-23T12:19:25Z

On Fri, Aug 23, 2019 at 5:40 PM Paolo Bonzini <pbonzini@redhat.com> wrote:
>
> On 23/08/19 13:44, Graf (AWS), Alexander wrote:
> >> Overall, I'm quite happy with the code. It's a very clean implementation
> >> of a KVM target.
>
> Yup, I said the same even for v1 (I prefer recursive implementation of
> page table walking but that's all I can say).
>
> >> I will send v6 next week. I will try my best to implement unpriv
> >> trap handling in v6 itself.
> > Are you sure unpriv is the only exception that can hit there? What
> > about NMIs? Do you have #MCs yet (ECC errors)? Do you have something
> > like ARM's #SError which can asynchronously hit at any time because
> > of external bus (PCI) errors?
>
> As far as I know, all interrupts on RISC-V are disabled by
> local_irq_disable()/local_irq_enable().

Yes, we don't have per-CPU interrupts for async bus errors or
non-maskable interrupts. The local_irq_disable() and local_irq_enable()
affect all interrupts (excepts traps).

Although, the async bus errors can certainly be routed to Linux
via PLIC (interrupt-controller) as regular peripheral interrupts.

Regards,
Anup

>
> Paolo