[PATCH v5 03/17] iommu/arm-smmu-v3: Move arm_smmu_rmr_install_bypass_ste()

[Mostafa Saleh]

Hi Jason,

On Tue, Feb 06, 2024 at 11:12:40AM -0400, Jason Gunthorpe wrote:
> Logically arm_smmu_init_strtab() is the function that allocates and
> populates the stream table with the initial value of the STEs. After this
> function returns the stream table should be fully ready.
> 
> arm_smmu_rmr_install_bypass_ste() adjusts the initial stream table to force
> any SIDs that the FW says have IOMMU_RESV_DIRECT to use bypass. This
> ensures there is no disruption to the identity mapping during boot.
> 
> Put arm_smmu_rmr_install_bypass_ste() into arm_smmu_init_strtab(), it
> already executes immediately after arm_smmu_init_strtab().
> 
> No functional change intended.

I think arm_smmu_init_strtab is quite low level to abstract FW configuration in it.
For example in KVM[1] we'd re-use a big part of this driver and rely on similar
low-level functions. But no strong opinion.

[1] https://lore.kernel.org/kvmarm/20230201125328.2186498-1-jean-philippe@linaro.org/


Thanks,
Mostafa

> Tested-by: Shameer Kolothum <shameerali.kolothum.thodi at huawei.com>
> Tested-by: Nicolin Chen <nicolinc at nvidia.com>
> Tested-by: Moritz Fischer <moritzf at google.com>
> Signed-off-by: Jason Gunthorpe <jgg at nvidia.com>
> ---
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> index 6123e5ad95822c..2ab36dcf7c61f5 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> @@ -101,6 +101,8 @@ static struct arm_smmu_option_prop arm_smmu_options[] = {
>  	{ 0, NULL},
>  };
>  
> +static void arm_smmu_rmr_install_bypass_ste(struct arm_smmu_device *smmu);
> +
>  static void parse_driver_options(struct arm_smmu_device *smmu)
>  {
>  	int i = 0;
> @@ -3256,6 +3258,7 @@ static int arm_smmu_init_strtab_linear(struct arm_smmu_device *smmu)
>  	cfg->strtab_base_cfg = reg;
>  
>  	arm_smmu_init_bypass_stes(strtab, cfg->num_l1_ents);
> +
>  	return 0;
>  }
>  
> @@ -3279,6 +3282,8 @@ static int arm_smmu_init_strtab(struct arm_smmu_device *smmu)
>  
>  	ida_init(&smmu->vmid_map);
>  
> +	/* Check for RMRs and install bypass STEs if any */
> +	arm_smmu_rmr_install_bypass_ste(smmu);
>  	return 0;
>  }
>  
> @@ -4073,9 +4078,6 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
>  	/* Record our private device structure */
>  	platform_set_drvdata(pdev, smmu);
>  
> -	/* Check for RMRs and install bypass STEs if any */
> -	arm_smmu_rmr_install_bypass_ste(smmu);
> -
>  	/* Reset the device */
>  	ret = arm_smmu_device_reset(smmu, bypass);
>  	if (ret)
> -- 
> 2.43.0
>