[PATCH v5 06/27] iommu/arm-smmu-v3: Consolidate clearing a CD table entry

[Michael Shavit]

On Tue, Mar 5, 2024 at 7:44 AM Jason Gunthorpe <jgg at nvidia.com> wrote:
>
> A cleared entry is all 0's. Make arm_smmu_clear_cd() do this sequence.
>
> If we are clearing an entry and for some reason it is not already
> allocated in the CD table then something has gone wrong.
>
> Tested-by: Nicolin Chen <nicolinc at nvidia.com>
> Signed-off-by: Jason Gunthorpe <jgg at nvidia.com>
> ---
>  .../iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c   |  2 +-
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c   | 20 ++++++++++++++-----
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h   |  2 ++
>  3 files changed, 18 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
> index 347c2fdd865c1a..bb9bb6fd7914ce 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
> @@ -558,7 +558,7 @@ void arm_smmu_sva_remove_dev_pasid(struct iommu_domain *domain,
>
>         mutex_lock(&sva_lock);
>
> -       arm_smmu_write_ctx_desc(master, id, NULL);
> +       arm_smmu_clear_cd(master, id);
>
>         list_for_each_entry(t, &master->bonds, list) {
>                 if (t->mm == mm) {
> 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 237fd6d92c880b..3fb4a1523d1d3f 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> @@ -1303,6 +1303,19 @@ static void arm_smmu_write_cd_entry(struct arm_smmu_master *master, int ssid,
>         arm_smmu_write_entry(&cd_writer.writer, cdptr->data, target->data);
>  }
>
> +void arm_smmu_clear_cd(struct arm_smmu_master *master, ioasid_t ssid)
> +{
> +       struct arm_smmu_cd target = {};
> +       struct arm_smmu_cd *cdptr;
> +
> +       if (!master->cd_table.cdtab)
> +               return;
> +       cdptr = arm_smmu_get_cd_ptr(master, ssid);
> +       if (WARN_ON(!cdptr))
> +               return;
> +       arm_smmu_write_cd_entry(master, ssid, cdptr, &target);
> +}
> +
>  int arm_smmu_write_ctx_desc(struct arm_smmu_master *master, int ssid,
>                             struct arm_smmu_ctx_desc *cd)
>  {
> @@ -2702,9 +2715,7 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
>         case ARM_SMMU_DOMAIN_S2:
>                 arm_smmu_make_s2_domain_ste(&target, master, smmu_domain);
>                 arm_smmu_install_ste_for_dev(master, &target);
> -               if (master->cd_table.cdtab)
> -                       arm_smmu_write_ctx_desc(master, IOMMU_NO_PASID,
> -                                                     NULL);
> +               arm_smmu_clear_cd(master, IOMMU_NO_PASID);
>                 break;
>         }
>
> @@ -2752,8 +2763,7 @@ static int arm_smmu_attach_dev_ste(struct device *dev,
>          * arm_smmu_domain->devices to avoid races updating the same context
>          * descriptor from arm_smmu_share_asid().
>          */
> -       if (master->cd_table.cdtab)
> -               arm_smmu_write_ctx_desc(master, IOMMU_NO_PASID, NULL);
> +       arm_smmu_clear_cd(master, IOMMU_NO_PASID);
>         return 0;
>  }
>
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> index 7078ed569fd4d3..87a7b57f566fbc 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> @@ -749,6 +749,8 @@ extern struct xarray arm_smmu_asid_xa;
>  extern struct mutex arm_smmu_asid_lock;
>  extern struct arm_smmu_ctx_desc quiet_cd;
>
> +void arm_smmu_clear_cd(struct arm_smmu_master *master, ioasid_t ssid);
> +
>  int arm_smmu_write_ctx_desc(struct arm_smmu_master *smmu_master, int ssid,
>                             struct arm_smmu_ctx_desc *cd);
>  void arm_smmu_tlb_inv_asid(struct arm_smmu_device *smmu, u16 asid);
> --
> 2.43.2
>
>
Reviewed-by: Michael Shavit <mshavit at google.com>