On Fri, Mar 7, 2025 at 4:55 AM Suthikulpanit, Suravee < [email protected]> wrote:
> > > On 3/5/2025 1:52 PM, Michael S. Tsirkin wrote: > > On Tue, Mar 04, 2025 at 06:37:47PM +0000, Suravee Suthikulpanit wrote: > >> The QEMU-emulated AMD IOMMU PCI device is implemented based on the AMD > I/O > >> Virtualization Technology (IOMMU) Specification [1]. The PCI id for this > >> device is platform-specific. > >> > >> Currently, the QEMU-emulated AMD IOMMU device is using AMD vendor id and > >> undefined device id. > > undefined? > > > >> Therefore, change the vendor id to Red Hat and request a new > QEMU-specific > >> device id. > > Won't the drivers fail to load then? > > > > > >> [1] > https://www.amd.com/content/dam/amd/en/documents/processor-tech-docs/ > >> specifications/48882_IOMMU.pdf > > what is this link teaching us? It's a 300 page document. Where to look > > in there? > > What I am trying to say is that all AMD IOMMU implementations must > adhere to this specification including the QEMU-emulated AMD IOMMU. > Unlike cpu emulation, we don't need to exactly mimic a particular > hardware implementation. > > QEMU-emulated AMD IOMMU device can have its own set of features that it > supports. Going forward, we might even have QEMU-specific feature / > behavior. So, we should not be using an existing PCI ID. > > And in this case how "other" (namely Windows) OSes will know how to use the device? > Thanks, > Suravee > >
