Hi Eric, > -----Original Message----- > From: qemu-devel- > [email protected] <qemu- > [email protected]> On > Behalf Of Eric Auger > Sent: Wednesday, March 12, 2025 3:36 PM > To: Shameerali Kolothum Thodi > <[email protected]>; [email protected]; > [email protected] > Cc: [email protected]; [email protected]; [email protected]; > [email protected]; [email protected]; [email protected]; > [email protected]; [email protected]; Linuxarm > <[email protected]>; Wangzhou (B) <[email protected]>; > jiangkunkun <[email protected]>; Jonathan Cameron > <[email protected]>; [email protected] > Subject: Re: [RFC PATCH v2 04/20] hw/arm/virt: Add support for smmuv3- > accel > > Hi Shameer, > > > On 3/11/25 3:10 PM, Shameer Kolothum wrote: > > Allow cold-plug smmuv3-accel to virt If the machine wide smmuv3 > > is not specified. > > > > No FDT support is added for now. > > > > Signed-off-by: Shameer Kolothum > <[email protected]> > > --- > > hw/arm/virt.c | 12 ++++++++++++ > > hw/core/sysbus-fdt.c | 1 + > > include/hw/arm/virt.h | 1 + > > 3 files changed, 14 insertions(+) > > > > diff --git a/hw/arm/virt.c b/hw/arm/virt.c > > index 4a5a9666e9..84a323da55 100644 > > --- a/hw/arm/virt.c > > +++ b/hw/arm/virt.c > > @@ -73,6 +73,7 @@ > > #include "qobject/qlist.h" > > #include "standard-headers/linux/input.h" > > #include "hw/arm/smmuv3.h" > > +#include "hw/arm/smmuv3-accel.h" > > #include "hw/acpi/acpi.h" > > #include "target/arm/cpu-qom.h" > > #include "target/arm/internals.h" > > @@ -2911,6 +2912,16 @@ static void > virt_machine_device_plug_cb(HotplugHandler *hotplug_dev, > > platform_bus_link_device(PLATFORM_BUS_DEVICE(vms- > >platform_bus_dev), > > SYS_BUS_DEVICE(dev)); > > } > > + if (object_dynamic_cast(OBJECT(dev), TYPE_ARM_SMMUV3_ACCEL)) > { > > + if (vms->iommu == VIRT_IOMMU_SMMUV3) { > maybe just check whether it is != VIRT_IOMMU_NONE? > > + error_setg(errp, > > + "iommu=smmuv3 is already specified. can't create > smmuv3-accel dev"); > I would clearly state "iommu=smmuv3 virt machine option is alreadt set" > and use an error hint to say both are not compatible. > > + return; > > + } > > + if (vms->iommu != VIRT_IOMMU_SMMUV3_ACCEL) { > > + vms->iommu = VIRT_IOMMU_SMMUV3_ACCEL; > > I know there were quite a lot of dicussions on the 1st multi > instantiation series related to the way we instanatiate that device and > maybe I missed some blockers but why wouldn't we allow the instantiation > of the legacy smmu device with -device too. I think this would be > simpler for libvirt and we would somehow deprecate the machine option > method? would that make a problem if you were to use -device smmu,accel > or something alike?
Thanks for taking a look. I am just jumping on this one for now. Yes, there were discussions around that. But I was not sure we concluded on deprecating the machine option. So if I get you correctly the idea is, if we have, -device smmuv3 it will instantiate the current machine wide smmuv3 and for -device smmuv3,accel this device? Thanks, Shameer
