Re: [RFC PATCH 3/5] qemu: Create PXBs and auto-assign VFIO devs and nested SMMUs

> Add a pcie-expander-bus controller to the VM definition for each "nestedSmmuv3" > device that is generated when the "nestedSmmuv3" IOMMU model is parsed from the > VM definition. Assign each "nestedSmmuv3" device to one PXB controller, and > route any unmanaged "hostdev" VFIO devices with associated host SMMU nodes to > their corresponding PXB controller based on the "name" attributes of > "nestedSmmuv3" devices attached to these PXB controllers. > > Signed-off-by: Nathan Chen<nathanc(a)nvidia.com> > --- > src/conf/domain_addr.c | 26 ++++++- > src/conf/domain_addr.h | 3 +- > src/conf/domain_conf.c | 1 + > src/qemu/qemu_domain_address.c | 134 +++++++++++++++++++++++++++++++++ > 4 files changed, 162 insertions(+), 2 deletions(-) > diff --git a/src/qemu/qemu_domain_address.c b/src/qemu/qemu_domain_address.c > index 31004bfc7e..dee198a7d2 100644 > --- a/src/qemu/qemu_domain_address.c > +++ b/src/qemu/qemu_domain_address.c > @@ -1627,6 +1627,19 @@ qemuDomainPCIAddressSetCreate(virDomainDef *def, > > addrs->dryRun = dryRun; > > + /* PXB indices must come before pcie-root-port indices in qemu, > + * so add PXB buses to addrs before the pcie-root-ports. */ Can you elaborate on that requirement - I don't get why QEMU cares which order slots are chosen in for PXB vs PCIe-Root-Port devices.