On Tue, 15 Apr 2025 09:11:03 +0100
Shameer Kolothum <shameerali.kolothum.th...@huawei.com> wrote:
> Allow cold-plug of smmuv3 device to virt If the machine wide smmuv3
> or a virtio-iommu is not specified.
>
> Also restrict the usage if virt <= 9.2. This will prevent accidently
> creating a SMMUv3 device on machines prior to 9.2 and cause failure
> on migrating to machines with same version but has a legacy smmuv3
> device.
Hi,
As we discussed internally I'm not convinced we need to prevent this particular
way for a user to shoot themselves in the foot.
To be a problem they have to specifically request an old machine + the
device that didn't exist for that machine, then migrate to a real old
version of QEMU. Agreed it is possible but I'm not sure we need to
prevent that particular crazy.
Jonathan
>
> Signed-off-by: Shameer Kolothum <shameerali.kolothum.th...@huawei.com>
> ---
> ToDo: probably need to change virt <= 9.2 to 10.0 considering the
> Qemu cycle we are at now.
> ---
> hw/arm/virt.c | 54 +++++++++++++++++++++++++++++++++++++++++++
> hw/core/sysbus-fdt.c | 3 +++
> include/hw/arm/virt.h | 1 +
> 3 files changed, 58 insertions(+)
>
> diff --git a/hw/arm/virt.c b/hw/arm/virt.c
> index 729f192558..8d0ae79f4d 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -56,6 +56,7 @@
> #include "qemu/cutils.h"
> #include "qemu/error-report.h"
> #include "qemu/module.h"
> +#include "hw/pci/pci_bus.h"
> #include "hw/pci-host/gpex.h"
> #include "hw/virtio/virtio-pci.h"
> #include "hw/core/sysbus-fdt.h"
> @@ -1445,6 +1446,31 @@ static void create_smmuv3_dt_bindings(const
> VirtMachineState *vms, hwaddr base,
> g_free(node);
> }
>
> +static void create_smmuv3_dev_dtb(VirtMachineState *vms,
> + DeviceState *dev)
> +{
> + PlatformBusDevice *pbus = PLATFORM_BUS_DEVICE(vms->platform_bus_dev);
> + SysBusDevice *sbdev = SYS_BUS_DEVICE(dev);
> + int irq = platform_bus_get_irqn(pbus, sbdev, 0);
> + hwaddr base = platform_bus_get_mmio_addr(pbus, sbdev, 0);
> + MachineState *ms = MACHINE(vms);
> + PCIBus *bus;
> +
> + bus = PCI_BUS(object_property_get_link(OBJECT(dev), "primary-bus",
> + &error_abort));
> + if (strcmp("pcie.0", bus->qbus.name)) {
> + warn_report("SMMUv3 device only supported with pcie.0 for DT");
> + return;
> + }
> + base += vms->memmap[VIRT_PLATFORM_BUS].base;
> + irq += vms->irqmap[VIRT_PLATFORM_BUS];
> +
> + vms->iommu_phandle = qemu_fdt_alloc_phandle(ms->fdt);
> + create_smmuv3_dt_bindings(vms, base, irq);
> + qemu_fdt_setprop_cells(ms->fdt, vms->pciehb_nodename, "iommu-map",
> + 0x0, vms->iommu_phandle, 0x0, 0x10000);
> +}
> +
> static void create_smmu(const VirtMachineState *vms,
> PCIBus *bus)
> {
> @@ -2944,6 +2970,18 @@ static void
> virt_machine_device_pre_plug_cb(HotplugHandler *hotplug_dev,
> qlist_append_str(reserved_regions, resv_prop_str);
> qdev_prop_set_array(dev, "reserved-regions", reserved_regions);
> g_free(resv_prop_str);
> + } else if (object_dynamic_cast(OBJECT(dev), TYPE_ARM_SMMUV3_DEV)) {
> + VirtMachineClass *vmc = VIRT_MACHINE_GET_CLASS(vms);
> +
> + if (vmc->no_smmuv3_device) {
> + error_setg(errp, "virt machine does not support
> arm-smmuv3-device");
> + } else if ((vms->iommu == VIRT_IOMMU_VIRTIO) ||
> + (vms->iommu == VIRT_IOMMU_SMMUV3)) {
> + error_setg(errp, "virt machine already has %s set."
> + "Doesn't support multiple incompatible iommus",
> + (vms->iommu == VIRT_IOMMU_VIRTIO) ?
> + "virtio-iommu" : "iommu=smmuv3");
> + }
> }
> }
>
> @@ -2967,6 +3005,19 @@ static void virt_machine_device_plug_cb(HotplugHandler
> *hotplug_dev,
> virtio_md_pci_plug(VIRTIO_MD_PCI(dev), MACHINE(hotplug_dev), errp);
> }
>
> + if (object_dynamic_cast(OBJECT(dev), TYPE_ARM_SMMUV3_DEV)) {
> + VirtMachineClass *vmc = VIRT_MACHINE_GET_CLASS(vms);
> +
> + create_smmuv3_dev_dtb(vms, dev);
> + if (vms->iommu != VIRT_IOMMU_SMMUV3_DEV) {
> + vms->iommu = VIRT_IOMMU_SMMUV3_DEV;
> + }
> + if (!vmc->no_nested_smmu) {
> + object_property_set_str(OBJECT(dev), "stage", "nested",
> + &error_fatal);
> + }
> + }
> +
> if (object_dynamic_cast(OBJECT(dev), TYPE_VIRTIO_IOMMU_PCI)) {
> PCIDevice *pdev = PCI_DEVICE(dev);
>
> @@ -3169,6 +3220,7 @@ static void virt_machine_class_init(ObjectClass *oc,
> void *data)
> machine_class_allow_dynamic_sysbus_dev(mc, TYPE_RAMFB_DEVICE);
> machine_class_allow_dynamic_sysbus_dev(mc, TYPE_VFIO_PLATFORM);
> machine_class_allow_dynamic_sysbus_dev(mc, TYPE_UEFI_VARS_SYSBUS);
> + machine_class_allow_dynamic_sysbus_dev(mc, TYPE_ARM_SMMUV3_DEV);
> #ifdef CONFIG_TPM
> machine_class_allow_dynamic_sysbus_dev(mc, TYPE_TPM_TIS_SYSBUS);
> #endif
> @@ -3418,8 +3470,10 @@ DEFINE_VIRT_MACHINE_AS_LATEST(10, 0)
>
> static void virt_machine_9_2_options(MachineClass *mc)
> {
> + VirtMachineClass *vmc = VIRT_MACHINE_CLASS(OBJECT_CLASS(mc));
> virt_machine_10_0_options(mc);
> compat_props_add(mc->compat_props, hw_compat_9_2, hw_compat_9_2_len);
> + vmc->no_smmuv3_device = true;
> }
> DEFINE_VIRT_MACHINE(9, 2)
>
> diff --git a/hw/core/sysbus-fdt.c b/hw/core/sysbus-fdt.c
> index e85066b905..ec90ed2c14 100644
> --- a/hw/core/sysbus-fdt.c
> +++ b/hw/core/sysbus-fdt.c
> @@ -31,6 +31,7 @@
> #include "qemu/error-report.h"
> #include "system/device_tree.h"
> #include "system/tpm.h"
> +#include "hw/arm/smmuv3.h"
> #include "hw/platform-bus.h"
> #include "hw/vfio/vfio-platform.h"
> #include "hw/vfio/vfio-calxeda-xgmac.h"
> @@ -512,6 +513,8 @@ static const BindingEntry bindings[] = {
> #ifdef CONFIG_LINUX
> TYPE_BINDING(TYPE_VFIO_CALXEDA_XGMAC, add_calxeda_midway_xgmac_fdt_node),
> TYPE_BINDING(TYPE_VFIO_AMD_XGBE, add_amd_xgbe_fdt_node),
> + /* No generic DT support for smmuv3 dev. Support added for arm virt only
> */
> + TYPE_BINDING(TYPE_ARM_SMMUV3_DEV, no_fdt_node),
> VFIO_PLATFORM_BINDING("amd,xgbe-seattle-v1a", add_amd_xgbe_fdt_node),
> #endif
> #ifdef CONFIG_TPM
> diff --git a/include/hw/arm/virt.h b/include/hw/arm/virt.h
> index 12395c7594..9f98345c92 100644
> --- a/include/hw/arm/virt.h
> +++ b/include/hw/arm/virt.h
> @@ -136,6 +136,7 @@ struct VirtMachineClass {
> bool no_tcg_lpa2;
> bool no_ns_el2_virt_timer_irq;
> bool no_nested_smmu;
> + bool no_smmuv3_device;
> };
>
> struct VirtMachineState {
