On Thu, 5 Jun 2025 12:36:52 +0000 Shameerali Kolothum Thodi <shameerali.kolothum.th...@huawei.com> wrote:
> > -----Original Message----- > > From: Igor Mammedov <imamm...@redhat.com> > > Sent: Thursday, June 5, 2025 1:20 PM > > To: Shameerali Kolothum Thodi <shameerali.kolothum.th...@huawei.com> > > Cc: Shameer Kolothum via <qemu-devel@nongnu.org>; qemu- > > a...@nongnu.org; eric.au...@redhat.com; peter.mayd...@linaro.org; > > j...@nvidia.com; nicol...@nvidia.com; ddut...@redhat.com; > > berra...@redhat.com; nath...@nvidia.com; mo...@nvidia.com; > > smost...@google.com; Linuxarm <linux...@huawei.com>; Wangzhou (B) > > <wangzh...@hisilicon.com>; jiangkunkun <jiangkun...@huawei.com>; > > Jonathan Cameron <jonathan.came...@huawei.com>; > > zhangfei....@linaro.org > > Subject: Re: [PATCH v3 1/6] hw/arm/smmuv3: Check SMMUv3 has PCIe Root > > Complex association > > [..] > > > > > in QEMU with PCI, usually we specify bus to attach to with 'bus' > > property, > > > > wouldn't it better to rename "primary-bus" to 'bus' to be consistent > > with > > > > the rest of PCI code (and before "primary-bus" shows up as a CLI option, > > > > so far (before this series) it looks like it's an internal property)? > > > > > > That was tried in v2 and since SMMUv3 is not a pci device by itself(it is > > > a > > > sysbus device) reusing the default "bus" property to establish an > > association > > > with a PCI bus created problems, > > > https://lore.kernel.org/qemu-devel/877c2ut0zk....@pond.sub.org/ > > > > that was an approach was trying to workaround by patching dc->bus_type, > > which is obviously wrong. > > > > I'm not talking about changing device type or something similar, > > but about renaming 'primary-bus' property name to 'bus' > > I have tried that earlier and gets this, > -device arm-smmuv3,bus=pcie.0,id=smmuv3.0: Device 'arm-smmuv3' can't go on > PCIE bus > > IIRC, the above mentioned patched dc->bus_type = TYPE_PCIE_BUS was used > to avoid that. > > Or am I missing something here? sigh, but you a right. qdev_device_add_from_qdict() && co can't handle that without heavy refactoring. > > so it would be consistent interface wise with PCI or other QEMU devices > > that are attached to a bus. > > > > > > > + if (!bus || !object_dynamic_cast(bus->parent, > > > > TYPE_PCI_HOST_BRIDGE)) { > > > > Also looking at smmu_base_realize, it has NULL pointer check already. > > > > Which also rises question, shouldn't smmu_base_realize check for > > > > TYPE_PCI_HOST_BRIDGE as well (aka can smmu be attached to anything > > > > else but a host bridge)? > > > > > > Not at the moment in Qemu. Though the SMMUv3 specification allows it > > to > > > be associated with non-pci devices as well. > > > > then perhaps move, the check to smmu_base_realize() for now? > > > > if smmu + non-pci ever materialize, it can be refactored at that time. > > Ok. > > Thanks, > Shameer >
