Re: [PATCH] pci-ids.rst: Add Red Hat pci-id for AMD IOMMU device

["Michael S. Tsirkin" <mst@redhat.com>]

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?

> Cc: Gerd Hoffmann <kraxel@redhat.com>
> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
> ---
>  docs/specs/pci-ids.rst | 2 ++
>  hw/i386/amd_iommu.c    | 3 ++-
>  include/hw/pci/pci.h   | 1 +
>  3 files changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/docs/specs/pci-ids.rst b/docs/specs/pci-ids.rst
> index 261b0f359f..2416a70a2d 100644
> --- a/docs/specs/pci-ids.rst
> +++ b/docs/specs/pci-ids.rst
> @@ -100,6 +100,8 @@ PCI devices (other than virtio):
>    PCI UFS device (``-device ufs``)
>  1b36:0014
>    PCI RISC-V IOMMU device
> +1b36:0015
> +  PCI AMD IOMMU device (``-device amd-iommu``)
>  
>  All these devices are documented in :doc:`index`.
>  
> diff --git a/hw/i386/amd_iommu.c b/hw/i386/amd_iommu.c
> index dda1a5781f..4d8564249c 100644
> --- a/hw/i386/amd_iommu.c
> +++ b/hw/i386/amd_iommu.c
> @@ -1766,7 +1766,8 @@ static void amdvi_pci_class_init(ObjectClass *klass, void *data)
>      DeviceClass *dc = DEVICE_CLASS(klass);
>      PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
>  
> -    k->vendor_id = PCI_VENDOR_ID_AMD;
> +    k->vendor_id = PCI_VENDOR_ID_REDHAT;
> +    k->device_id = PCI_DEVICE_ID_REDHAT_AMD_IOMMU;
>      k->class_id = 0x0806;
>      k->realize = amdvi_pci_realize;
>  
> diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
> index 4002bbeebd..da44e6673d 100644
> --- a/include/hw/pci/pci.h
> +++ b/include/hw/pci/pci.h
> @@ -117,6 +117,7 @@ extern bool pci_available;
>  #define PCI_DEVICE_ID_REDHAT_ACPI_ERST   0x0012
>  #define PCI_DEVICE_ID_REDHAT_UFS         0x0013
>  #define PCI_DEVICE_ID_REDHAT_RISCV_IOMMU 0x0014
> +#define PCI_DEVICE_ID_REDHAT_AMD_IOMMU   0x0015
>  #define PCI_DEVICE_ID_REDHAT_QXL         0x0100
>  
>  #define FMT_PCIBUS                      PRIx64
> -- 
> 2.34.1