[PATCH v6 06/29] iommu/arm-smmu-v3: Add an ops indirection to the STE code

[Will Deacon]

On Wed, Mar 27, 2024 at 03:07:52PM -0300, Jason Gunthorpe wrote:
> Prepare to put the CD code into the same mechanism. Add an ops indirection
> around all the STE specific code and make the worker functions independent
> of the entry content being processed.
> 
> get_used and sync ops are provided to hook the correct code.
> 
> Signed-off-by: Michael Shavit <mshavit at google.com>
> Reviewed-by: Michael Shavit <mshavit at google.com>
> Tested-by: Nicolin Chen <nicolinc at nvidia.com>
> Tested-by: Shameer Kolothum <shameerali.kolothum.thodi at huawei.com>
> Signed-off-by: Jason Gunthorpe <jgg at nvidia.com>
> ---
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 170 ++++++++++++--------
>  1 file changed, 102 insertions(+), 68 deletions(-)

Any chance we can pull the STE testing stuff forward from Michael once
we have the entry writing ops indirection, please? It would be nice to
land that before adding the CD support, I think.

> @@ -1102,17 +1111,14 @@ static bool entry_set(struct arm_smmu_device *smmu, ioasid_t sid,
>   * V=0 process. This relies on the IGNORED behavior described in the
>   * specification.
>   */
> -static void arm_smmu_write_ste(struct arm_smmu_master *master, u32 sid,
> -			       struct arm_smmu_ste *entry,
> -			       const struct arm_smmu_ste *target)
> +static void arm_smmu_write_entry(struct arm_smmu_entry_writer *writer,
> +				 __le64 *entry, const __le64 *target)
>  {
> -	unsigned int num_entry_qwords = ARRAY_SIZE(target->data);
> -	struct arm_smmu_device *smmu = master->smmu;
> -	struct arm_smmu_ste unused_update;
> +	__le64 unused_update[NUM_ENTRY_QWORDS];
>  	u8 used_qword_diff;
>  
>  	used_qword_diff =
> -		arm_smmu_entry_qword_diff(entry, target, &unused_update);
> +		arm_smmu_entry_qword_diff(writer, entry, target, unused_update);
>  	if (hweight8(used_qword_diff) == 1) {
>  		/*
>  		 * Only one qword needs its used bits to be changed. This is a

nit: This comment (lost in the diff context) refers to STEs a couple of
times. Please update to e.g. "STE/CD".

Will