Re: [PATCH v2 22/22] iommu/tegra241-cmdqv: Add IOMMU_VEVENTQ_TYPE_TEGRA241_CMDQV support

[Pranjal Shrivastava <praan@google.com>]

On Fri, Apr 25, 2025 at 10:58:17PM -0700, Nicolin Chen wrote:
> Add a new vEVENTQ type for VINTFs that are assigned to the user space.
> Simply report the two 64-bit LVCMDQ_ERR_MAPs register values.
> 
> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>

Reviewed-by: Pranjal Shrivastava <praan@google.com>

Thanks,
Praan

> ---
>  include/uapi/linux/iommufd.h                  | 15 +++++++++++++
>  .../iommu/arm/arm-smmu-v3/tegra241-cmdqv.c    | 22 +++++++++++++++++++
>  2 files changed, 37 insertions(+)
> 
> diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
> index d69e7c1d39ea..d814b0f61fad 100644
> --- a/include/uapi/linux/iommufd.h
> +++ b/include/uapi/linux/iommufd.h
> @@ -1113,10 +1113,12 @@ struct iommufd_vevent_header {
>   * enum iommu_veventq_type - Virtual Event Queue Type
>   * @IOMMU_VEVENTQ_TYPE_DEFAULT: Reserved for future use
>   * @IOMMU_VEVENTQ_TYPE_ARM_SMMUV3: ARM SMMUv3 Virtual Event Queue
> + * @IOMMU_VEVENTQ_TYPE_TEGRA241_CMDQV: NVIDIA Tegra241 CMDQV Extension IRQ
>   */
>  enum iommu_veventq_type {
>  	IOMMU_VEVENTQ_TYPE_DEFAULT = 0,
>  	IOMMU_VEVENTQ_TYPE_ARM_SMMUV3 = 1,
> +	IOMMU_VEVENTQ_TYPE_TEGRA241_CMDQV = 2,
>  };
>  
>  /**
> @@ -1140,6 +1142,19 @@ struct iommu_vevent_arm_smmuv3 {
>  	__aligned_le64 evt[4];
>  };
>  
> +/**
> + * struct iommu_vevent_tegra241_cmdqv - Tegra241 CMDQV IRQ
> + *                                      (IOMMU_VEVENTQ_TYPE_TEGRA241_CMDQV)
> + * @lvcmdq_err_map: 128-bit logical vcmdq error map, little-endian.
> + *                  (Refer to register LVCMDQ_ERR_MAPs per VINTF )
> + *
> + * The 128-bit register value from HW exclusively reflect the error bits for a
> + * Virtual Interface represented by a vIOMMU object. Read and report directly.
> + */
> +struct iommu_vevent_tegra241_cmdqv {
> +	__aligned_le64 lvcmdq_err_map[2];
> +};
> +
>  /**
>   * struct iommu_veventq_alloc - ioctl(IOMMU_VEVENTQ_ALLOC)
>   * @size: sizeof(struct iommu_veventq_alloc)
> diff --git a/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c b/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c
> index 88e2b6506b3a..d8830b526601 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/tegra241-cmdqv.c
> @@ -292,6 +292,20 @@ static inline int vcmdq_write_config(struct tegra241_vcmdq *vcmdq, u32 regval)
>  
>  /* ISR Functions */
>  
> +static void tegra241_vintf_user_handle_error(struct tegra241_vintf *vintf)
> +{
> +	struct iommufd_viommu *viommu = &vintf->vsmmu.core;
> +	struct iommu_vevent_tegra241_cmdqv vevent_data;
> +	int i;
> +
> +	for (i = 0; i < LVCMDQ_ERR_MAP_NUM_64; i++)
> +		vevent_data.lvcmdq_err_map[i] =
> +			readq_relaxed(REG_VINTF(vintf, LVCMDQ_ERR_MAP_64(i)));
> +
> +	iommufd_viommu_report_event(viommu, IOMMU_VEVENTQ_TYPE_TEGRA241_CMDQV,
> +				    &vevent_data, sizeof(vevent_data));
> +}
> +
>  static void tegra241_vintf0_handle_error(struct tegra241_vintf *vintf)
>  {
>  	int i;
> @@ -337,6 +351,14 @@ static irqreturn_t tegra241_cmdqv_isr(int irq, void *devid)
>  		vintf_map &= ~BIT_ULL(0);
>  	}
>  
> +	/* Handle other user VINTFs and their LVCMDQs */
> +	while (vintf_map) {
> +		unsigned long idx = __ffs64(vintf_map);
> +
> +		tegra241_vintf_user_handle_error(cmdqv->vintfs[idx]);
> +		vintf_map &= ~BIT_ULL(idx);
> +	}
> +
>  	return IRQ_HANDLED;
>  }
>  
> -- 
> 2.43.0
>