RE: [RFC PATCH 4/5] hw/arm/virt-acpi-build: Build IORT with multiple SMMU nodes

[Shameerali Kolothum Thodi via <qemu-devel@nongnu.org>]

> -----Original Message-----
> From: Eric Auger <eric.auger@redhat.com>
> Sent: Monday, November 18, 2024 10:02 AM
> To: Shameerali Kolothum Thodi
> <shameerali.kolothum.thodi@huawei.com>; qemu-arm@nongnu.org;
> qemu-devel@nongnu.org
> Cc: peter.maydell@linaro.org; jgg@nvidia.com; nicolinc@nvidia.com;
> ddutile@redhat.com; Linuxarm <linuxarm@huawei.com>; Wangzhou (B)
> <wangzhou1@hisilicon.com>; jiangkunkun <jiangkunkun@huawei.com>;
> Jonathan Cameron <jonathan.cameron@huawei.com>;
> zhangfei.gao@linaro.org
> Subject: Re: [RFC PATCH 4/5] hw/arm/virt-acpi-build: Build IORT with
> multiple SMMU nodes
> 

> >      /* Number of IORT Nodes */
> > @@ -342,10 +356,9 @@ build_iort(GArray *table_data, BIOSLinker
> *linker, VirtMachineState *vms)
> >      /* GIC ITS Identifier Array */
> >      build_append_int_noprefix(table_data, 0 /* MADT translation_id */,
> 4);
> >
> > -    if (vms->iommu == VIRT_IOMMU_SMMUV3) {
> > -        int irq =  vms->irqmap[VIRT_SMMU] + ARM_SPI_BASE;
> > +    for (i = 0; i < num_smmus; i++) {
> > +        smmu_offset[i] = table_data->len - table.table_offset;
> >
> I would have expected changes in the smmu idmap has well. If a given
> SMMU instance now protects a given bus hierarchy shouldn't it be
> reflected in a differentiated SMMU idmap for each of them (RID subset of
> SMMU->pci-bus mapping to a specific IORT SMMU node)? How is it done
> currently?

I thought that smmu_idmaps will be handled by this ?

object_child_foreach_recursive(object_get_root(),
                                       iort_host_bridges, smmu_idmaps);

But it is possible that, there is a bug in this IORT generation here as I am not
able to hot add  devices. It looks like the pciehp interrupt is not generated/received
for some reason. Nicolin[0] is suspecting the min/max bus range in
iort_host_bridges() may not leave enough ranges for hot add later.

Cold plugging devices to different SMMUv3/pcie-pxb seems to be alright.

I will debug that soon.

Thanks,
Shameer
[0] https://lore.kernel.org/qemu-devel/ZzPd1F%2FUA2MKMbwl@Asurada-Nvidia/