RE: [RFC PATCH v2 04/20] hw/arm/virt: Add support for smmuv3-accel

[Shameerali Kolothum Thodi via]

> -----Original Message-----
> From: Nicolin Chen <nicol...@nvidia.com>
> Sent: Tuesday, March 11, 2025 8:23 PM
> To: Shameerali Kolothum Thodi <shameerali.kolothum.th...@huawei.com>
> Cc: qemu-...@nongnu.org; qemu-devel@nongnu.org;
> eric.au...@redhat.com; peter.mayd...@linaro.org; j...@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: [RFC PATCH v2 04/20] hw/arm/virt: Add support for smmuv3-
> accel
> 
> On Tue, Mar 11, 2025 at 02:10:29PM +0000, 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
> <shameerali.kolothum.th...@huawei.com>
> > ---
> >  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"
> 
> smmuv3-accel.h included smmuv3.h in the patch prior.
> 
> > @@ -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) {
> > +                error_setg(errp,
> > +                           "iommu=smmuv3 is already specified. can't create
> smmuv3-accel dev");
> > +                return;
> > +            }
> > +            if (vms->iommu != VIRT_IOMMU_SMMUV3_ACCEL) {
> > +                vms->iommu = VIRT_IOMMU_SMMUV3_ACCEL;
> > +            }
> 
> Looks like it is to support TYPE_VIRTIO_IOMMU_PCI?
>
> Just asking: should SMMUV3_ACCEL work with that?

Hmm..That's true. It will conflict with virtio-iommu. I will add
a blocker if both are specified.

Thanks,
Shameer