RE: [PATCH 0/5] Add support for user creatable SMMUv3 device

[Shameerali Kolothum Thodi via <qemu-arm@nongnu.org>]

Hi Eric,

> -----Original Message-----
> From: Eric Auger <eric.auger@redhat.com>
> Sent: Wednesday, April 30, 2025 6:48 PM
> To: Donald Dutile <ddutile@redhat.com>; Shameerali Kolothum Thodi
> <shameerali.kolothum.thodi@huawei.com>; qemu-arm@nongnu.org;
> qemu-devel@nongnu.org
> Cc: peter.maydell@linaro.org; jgg@nvidia.com; nicolinc@nvidia.com;
> berrange@redhat.com; nathanc@nvidia.com; mochs@nvidia.com;
> smostafa@google.com; Linuxarm <linuxarm@huawei.com>; Wangzhou (B)
> <wangzhou1@hisilicon.com>; jiangkunkun <jiangkunkun@huawei.com>;
> Jonathan Cameron <jonathan.cameron@huawei.com>;
> zhangfei.gao@linaro.org
> Subject: Re: [PATCH 0/5] Add support for user creatable SMMUv3 device
> 
> Hi Shameer,
> 
> On 4/28/25 8:41 PM, Donald Dutile wrote:
> >
> >
> > On 4/22/25 4:57 AM, Shameerali Kolothum Thodi wrote:
> >>
> >>> -----Original Message-----
> >>> From: Donald Dutile <ddutile@redhat.com>
> >>> Sent: Friday, April 18, 2025 9:34 PM
> >>> To: Shameerali Kolothum Thodi
> >>> <shameerali.kolothum.thodi@huawei.com>; qemu-arm@nongnu.org;
> >>> qemu-devel@nongnu.org
> >>> Cc: eric.auger@redhat.com; peter.maydell@linaro.org; jgg@nvidia.com;
> >>> nicolinc@nvidia.com; berrange@redhat.com; nathanc@nvidia.com;
> >>> mochs@nvidia.com; smostafa@google.com; Linuxarm
> >>> <linuxarm@huawei.com>; Wangzhou (B) <wangzhou1@hisilicon.com>;
> >>> jiangkunkun <jiangkunkun@huawei.com>; Jonathan Cameron
> >>> <jonathan.cameron@huawei.com>; zhangfei.gao@linaro.org
> >>> Subject: Re: [PATCH 0/5] Add support for user creatable SMMUv3
> device
> >>>
> >>> Shameer,
> >>> Hi!
> >>>
> >>> First off, like the partitioning of these pieces.
> >>>
> >>> On 4/15/25 4:10 AM, Shameer Kolothum wrote:
> >>>> Hi All,
> >>>>
> >>>> This patch series introduces support for a user-creatable SMMUv3
> >>>> device
> >>>> (-device arm-smmuv3-dev) in QEMU.
> >>>>
> >>> Can we drop the '-dev', as 'arm-smmu' is sufficient, as is '-device'?
> >>>
> >>> I know, internal to QEMU, there's already an ARM_SMMU, but as
> suggested
> >>> later,
> >>> if it uses the same struct, the qemu cmdline syntax is a bit less
> >>> redundant.
> >>
> >> Trust me I tried that😊. The problem is that, the legacy one doesn't
> >> have a bus
> >> associated with it and the moment we change that and have bus
> >> specified for the
> >>   "-device arm-smmuv3, bus=pcie.0" the legacy smmuv3 creation in virt,
> >>
> >> create_smmu() --> qdev_new(TYPE_ARM_SMMUV3)
> I have the impression you can achieve your goal by replacing
> sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal);
> by
> qdev_realize_and_unref(dev, &bus->qbus, &error_fatal);
> See https://github.com/eauger/qemu/tree/arm-smmuv3-dev-rc0

Cool!. That does the trick. Thanks.
 
> and its top patch.
> 
> indeed it would be better if we could reuse the same device.

I will respin soon with the above and addressing other comments received.

Thanks,
Shameer