Re: [PATCH 4/8] acpi_build: Use IOMMU pci device to build IOMMU device ID

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

On Mon, May 11, 2026 at 06:09:33PM +0530, Sairaj Kodilkar wrote:
> Currently, build_amd_iommu() uses "addr" property to build the device ID for
> IOMMU device and advertise it throught IVRS. But this property does not encode
> IOMMU bus. This will be a problem if IOMMU is attached to different bus.
> Hence use iommu pci device which provides bus, to build the IOMMU device ID.
> 
> Signed-off-by: Sairaj Kodilkar <sarunkod@amd.com>
> Reviewed-by: Vasant Hegde <vasant.hegde@amd.com>

But is this called after firmware has enumerated the pci bus?
And I guess OS better not change that bus number eh?

> ---
>  hw/i386/acpi-build.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index e4ad01eec037..718e3f546b18 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -1752,10 +1752,13 @@ build_amd_iommu(GArray *table_data, BIOSLinker *linker, const char *oem_id,
>                  const char *oem_table_id)
>  {
>      AMDVIState *s = AMD_IOMMU_DEVICE(x86_iommu_get_default());
> +    PCIDevice *iommu_dev = &(s->pci->dev);
>      GArray *ivhd_blob = g_array_new(false, true, 1);
>      AcpiTable table = { .sig = "IVRS", .rev = 1, .oem_id = oem_id,
>                          .oem_table_id = oem_table_id };
>      uint64_t feature_report;
> +    int iommu_bus = pci_bus_num(pci_get_bus(iommu_dev));
> +    uint16_t iommu_devid = PCI_BUILD_BDF(iommu_bus, iommu_dev->devfn);
>  
>      acpi_table_begin(&table, table_data);
>      /* IVinfo - IO virtualization information common to all
> @@ -1816,9 +1819,7 @@ build_amd_iommu(GArray *table_data, BIOSLinker *linker, const char *oem_id,
>      /* IVHD length */
>      build_append_int_noprefix(table_data, ivhd_blob->len + 24, 2);
>      /* DeviceID */
> -    build_append_int_noprefix(table_data,
> -                              object_property_get_int(OBJECT(s->pci), "addr",
> -                                                      &error_abort), 2);
> +    build_append_int_noprefix(table_data, iommu_devid, 2);
>      /* Capability offset */
>      build_append_int_noprefix(table_data, s->pci->capab_offset, 2);
>      /* IOMMU base address */
> @@ -1850,10 +1851,9 @@ build_amd_iommu(GArray *table_data, BIOSLinker *linker, const char *oem_id,
>  
>      /* IVHD length */
>      build_append_int_noprefix(table_data, ivhd_blob->len + 40, 2);
> +
>      /* DeviceID */
> -    build_append_int_noprefix(table_data,
> -                              object_property_get_int(OBJECT(s->pci), "addr",
> -                                                      &error_abort), 2);
> +    build_append_int_noprefix(table_data, iommu_devid, 2);
>      /* Capability offset */
>      build_append_int_noprefix(table_data, s->pci->capab_offset, 2);
>      /* IOMMU base address */
> -- 
> 2.34.1