Re: [PATCH v4 0/4] Support RISC-V IOPMP

[Alistair Francis]

On Thu, Dec 21, 2023 at 4:38 PM Ethan Chen <ethan84@andestech.com> wrote:
>
> On Mon, Dec 18, 2023 at 02:18:58PM +1000, Alistair Francis wrote:
> > On Wed, Nov 22, 2023 at 3:36 PM Ethan Chen via <qemu-devel@nongnu.org> 
> > wrote:
> > >
> > > This series implements IOPMP specification v1.0.0-draft4 rapid-k model.
> > > The specification url:
> > > https://github.com/riscv-non-isa/iopmp-spec/blob/main/riscv_iopmp_specification.pdf
> > >
> > > When IOPMP is enabled, a DMA device ATCDMAC300 is added to RISC-V virt
> > > platform. This DMA device is connected to the IOPMP and has the 
> > > functionalities
> >
> > I don't think we want to add an Andes DMA device to the virt machine.
> >
> > I can't even find the spec for the ATCDMAC300, which isn't great
> >
> > Alistair
>
> Since the IOPMP does not take effect when there is no other device connects to
> IOPMP, I think it is necessary to have a DMA device for IOPMP demonstration.

That is true, but that device shouldn't be a vendor specific device
for the virt machine.

>
> Do you have any suggestions for supporting IOPMP on RISC-V virt machine?

A RVI device would be fine. Otherwise something that has become a
defacto standard by being commonly used (the SiFive PLIC for example).

I really don't think it should be some vendor IP, especially one that
doesn't have a public datasheet.

You could add an Andes machine that can use your vendor IP. Otherwise
we can look at adding IOPMP and not connecting it, but that is a pain.

What is the IOPMP spec group doing for testing?

Alistair