Re: [PATCH v2 1/5] pci-ids: drop PCI_DEVICE_ID_VIRTIO_IOMMU

[Peter Maydell]

On Fri, 30 Sept 2022 at 14:58, Gerd Hoffmann <kraxel@redhat.com> wrote:
>
> Not needed for a virtio 1.0 device.
>
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> ---
>  include/hw/pci/pci.h         | 1 -
>  hw/virtio/virtio-iommu-pci.c | 4 +---
>  2 files changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
> index b54b6ef88fc3..89eaca429389 100644
> --- a/include/hw/pci/pci.h
> +++ b/include/hw/pci/pci.h
> @@ -85,7 +85,6 @@ extern bool pci_available;
>  #define PCI_DEVICE_ID_VIRTIO_9P          0x1009
>  #define PCI_DEVICE_ID_VIRTIO_VSOCK       0x1012
>  #define PCI_DEVICE_ID_VIRTIO_PMEM        0x1013
> -#define PCI_DEVICE_ID_VIRTIO_IOMMU       0x1014
>  #define PCI_DEVICE_ID_VIRTIO_MEM         0x1015
>
>  #define PCI_VENDOR_ID_REDHAT             0x1b36
> diff --git a/hw/virtio/virtio-iommu-pci.c b/hw/virtio/virtio-iommu-pci.c
> index 844d64770406..79ea8334f04e 100644
> --- a/hw/virtio/virtio-iommu-pci.c
> +++ b/hw/virtio/virtio-iommu-pci.c
> @@ -74,8 +74,6 @@ static void virtio_iommu_pci_class_init(ObjectClass *klass, 
> void *data)
>      k->realize = virtio_iommu_pci_realize;
>      set_bit(DEVICE_CATEGORY_MISC, dc->categories);
>      device_class_set_props(dc, virtio_iommu_pci_properties);
> -    pcidev_k->vendor_id = PCI_VENDOR_ID_REDHAT_QUMRANET;
> -    pcidev_k->device_id = PCI_DEVICE_ID_VIRTIO_IOMMU;
>      pcidev_k->revision = VIRTIO_PCI_ABI_VERSION;
>      pcidev_k->class_id = PCI_CLASS_OTHERS;
>      dc->hotpluggable = false;

So does this mean:
 * these ID values on the device were never used, because some
   other code always overwrites them with the 'modern' ID values?
   If so, what is that other code?
 * this is a change in behaviour? If so, what does the PCI
   device show up as if you don't set these fields at all?
   Do we need to make this only-in-new-machine-versions?

thanks
-- PMM