Re: [PATCH v3 06/32] hw/arm/tegra241-cmdqv: Add Tegra241 CMDQV ops backend stub

[Eric Auger <eric.auger@redhat.com>]

Hi Shameer,

On 2/26/26 11:50 AM, Shameer Kolothum wrote:
> Introduce a Tegra241 CMDQV backend that plugs into the SMMUv3 accelerated
> CMDQV ops interface.
>
> This patch wires up the Tegra241 CMDQV backend and provides a stub
> implementation for CMDQV probe, initialization, vIOMMU allocation
> and reset handling.
>
> Functional CMDQV support is added in follow-up patches.
>
> Signed-off-by: Shameer Kolothum <skolothumtho@nvidia.com>
> ---
>  hw/arm/tegra241-cmdqv.h       | 15 ++++++++++
>  hw/arm/tegra241-cmdqv-stubs.c | 18 +++++++++++
>  hw/arm/tegra241-cmdqv.c       | 56 +++++++++++++++++++++++++++++++++++
>  hw/arm/Kconfig                |  5 ++++
>  hw/arm/meson.build            |  2 ++
>  5 files changed, 96 insertions(+)
>  create mode 100644 hw/arm/tegra241-cmdqv.h
>  create mode 100644 hw/arm/tegra241-cmdqv-stubs.c
>  create mode 100644 hw/arm/tegra241-cmdqv.c
>
> diff --git a/hw/arm/tegra241-cmdqv.h b/hw/arm/tegra241-cmdqv.h
> new file mode 100644
> index 0000000000..07e10e86ee
> --- /dev/null
> +++ b/hw/arm/tegra241-cmdqv.h
> @@ -0,0 +1,15 @@
> +/*
> + * Copyright (c) 2025-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved
> + * NVIDIA Tegra241 CMDQ-Virtualiisation extension for SMMUv3
> + *
> + * Written by Nicolin Chen, Shameer Kolothum
> + *
> + * SPDX-License-Identifier: GPL-2.0-or-later
> + */
> +
> +#ifndef HW_ARM_TEGRA241_CMDQV_H
> +#define HW_ARM_TEGRA241_CMDQV_H
> +
> +const SMMUv3AccelCmdqvOps *tegra241_cmdqv_get_ops(void);
> +
> +#endif /* HW_ARM_TEGRA241_CMDQV_H */
> diff --git a/hw/arm/tegra241-cmdqv-stubs.c b/hw/arm/tegra241-cmdqv-stubs.c
> new file mode 100644
> index 0000000000..eedc7bfdcd
> --- /dev/null
> +++ b/hw/arm/tegra241-cmdqv-stubs.c
> @@ -0,0 +1,18 @@
> +/*
> + * Copyright (c) 2025-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved
> + *
> + * Stubs for Tegra241 CMDQ-Virtualiisation extension for SMMUv3
> + *
> + * SPDX-License-Identifier: GPL-2.0-or-later
> + */
> +
> +#include "qemu/osdep.h"
> +#include "hw/arm/smmuv3.h"
> +#include "smmuv3-accel.h"
> +#include "hw/arm/tegra241-cmdqv.h"
not sure you need all those headers for the stub

Eric
> +
> +const SMMUv3AccelCmdqvOps *tegra241_cmdqv_get_ops(void)
> +{
> +    return NULL;
> +}
> +
> diff --git a/hw/arm/tegra241-cmdqv.c b/hw/arm/tegra241-cmdqv.c
> new file mode 100644
> index 0000000000..ad5a0d4611
> --- /dev/null
> +++ b/hw/arm/tegra241-cmdqv.c
> @@ -0,0 +1,56 @@
> +/*
> + * Copyright (c) 2025-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved
> + * NVIDIA Tegra241 CMDQ-Virtualization extension for SMMUv3
> + *
> + * Written by Nicolin Chen, Shameer Kolothum
> + *
> + * SPDX-License-Identifier: GPL-2.0-or-later
> + */
> +
> +#include "qemu/osdep.h"
> +
> +#include "hw/arm/smmuv3.h"
> +#include "smmuv3-accel.h"
> +#include "tegra241-cmdqv.h"
> +
> +static void tegra241_cmdqv_free_viommu(SMMUv3State *s)
> +{
> +}
> +
> +static bool
> +tegra241_cmdqv_alloc_viommu(SMMUv3State *s, HostIOMMUDeviceIOMMUFD *idev,
> +                            uint32_t *out_viommu_id, Error **errp)
> +{
> +    error_setg(errp, "NVIDIA Tegra241 CMDQV is unsupported");
> +    return false;
> +}
> +
> +static void tegra241_cmdqv_reset(SMMUv3State *s)
> +{
> +}
> +
> +static bool tegra241_cmdqv_init(SMMUv3State *s, Error **errp)
> +{
> +    error_setg(errp, "NVIDIA Tegra241 CMDQV is unsupported");
> +    return false;
> +}
> +
> +static bool tegra241_cmdqv_probe(SMMUv3State *s, HostIOMMUDeviceIOMMUFD *idev,
> +                                 Error **errp)
> +{
> +    error_setg(errp, "NVIDIA Tegra241 CMDQV is unsupported");
> +    return false;
> +}
> +
> +static const SMMUv3AccelCmdqvOps tegra241_cmdqv_ops = {
> +    .probe = tegra241_cmdqv_probe,
> +    .init = tegra241_cmdqv_init,
> +    .alloc_viommu = tegra241_cmdqv_alloc_viommu,
> +    .free_viommu = tegra241_cmdqv_free_viommu,
> +    .reset = tegra241_cmdqv_reset,
> +};
> +
> +const SMMUv3AccelCmdqvOps *tegra241_cmdqv_get_ops(void)
> +{
> +    return &tegra241_cmdqv_ops;
> +}
> diff --git a/hw/arm/Kconfig b/hw/arm/Kconfig
> index c66c452737..3305c6e76e 100644
> --- a/hw/arm/Kconfig
> +++ b/hw/arm/Kconfig
> @@ -626,6 +626,10 @@ config FSL_IMX8MP_EVK
>      depends on TCG
>      select FSL_IMX8MP
>  
> +config TEGRA241_CMDQV
> +    bool
> +    depends on ARM_SMMUV3_ACCEL
> +
>  config ARM_SMMUV3_ACCEL
>      bool
>      depends on ARM_SMMUV3
> @@ -633,6 +637,7 @@ config ARM_SMMUV3_ACCEL
>  config ARM_SMMUV3
>      bool
>      select ARM_SMMUV3_ACCEL if IOMMUFD
> +    imply TEGRA241_CMDQV
>  
>  config FSL_IMX6UL
>      bool
> diff --git a/hw/arm/meson.build b/hw/arm/meson.build
> index 8f834c32b1..fc83b635e7 100644
> --- a/hw/arm/meson.build
> +++ b/hw/arm/meson.build
> @@ -88,6 +88,8 @@ arm_common_ss.add(when: 'CONFIG_FSL_IMX8MP_EVK', if_true: files('imx8mp-evk.c'))
>  arm_common_ss.add(when: 'CONFIG_ARM_SMMUV3', if_true: files('smmuv3.c'))
>  arm_common_ss.add(when: 'CONFIG_ARM_SMMUV3_ACCEL', if_true: files('smmuv3-accel.c'))
>  stub_ss.add(files('smmuv3-accel-stubs.c'))
> +arm_common_ss.add(when: 'CONFIG_TEGRA241_CMDQV', if_true: files('tegra241-cmdqv.c'))
> +stub_ss.add(files('tegra241-cmdqv-stubs.c'))
>  arm_common_ss.add(when: 'CONFIG_FSL_IMX6UL', if_true: files('fsl-imx6ul.c', 'mcimx6ul-evk.c'))
>  arm_common_ss.add(when: 'CONFIG_NRF51_SOC', if_true: files('nrf51_soc.c'))
>  arm_common_ss.add(when: 'CONFIG_XEN', if_true: files(