Re: [PATCH 06/11] RISC-V: drivers/iommu/riscv: Add command, fault, page-req queues

[Nick Kossifidis]

On 7/31/23 16:15, Zong Li wrote:
> On Mon, Jul 31, 2023 at 5:32 PM Nick Kossifidis <mick@xxxxxxxxxxxx> wrote:
> > On 7/29/23 15:58, Zong Li wrote:
> > > On Thu, Jul 20, 2023 at 3:34 AM Tomasz Jeznach <tjeznach@xxxxxxxxxxxx> wrote:
> > > > +       iommu->cap = riscv_iommu_readq(iommu, RISCV_IOMMU_REG_CAP);
> > > > +
> > > > +       /* For now we only support WSIs until we have AIA support */
> > >
> > > I'm not completely understand AIA support here, because I saw the pci
> > > case uses the MSI, and kernel seems to have the AIA implementation.
> > > Could you please elaborate it?
> >
> > When I wrote this we didn't have AIA in the kernel, and without IMSIC we
> > can't have MSIs in the hart (we can still have MSIs in the PCIe controller).
>
> Thanks for your clarification, do we support the MSI in next version?

I don't think there is an IOMMU implementation out there (emulated or in 
hw) that can do MSIs and is not a pcie device (the QEMU implementation 
is a pcie device). If we have something to test this against, and we 
also have an IMSIC etc, we can work on that.