Re: [PATCH v4 09/13] iommu/arm-smmu-v3: Prepare for handling arm_smmu_write_ctx_desc() failure

[Will Deacon <will@kernel.org>]

On Thu, Dec 19, 2019 at 05:30:29PM +0100, Jean-Philippe Brucker wrote:
> Second-level context descriptor tables will be allocated lazily in
> arm_smmu_write_ctx_desc(). Help with handling allocation failure by
> moving the CD write into arm_smmu_domain_finalise_s1().
> 
> Reviewed-by: Eric Auger <eric.auger@redhat.com>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> ---
>  drivers/iommu/arm-smmu-v3.c | 11 +++++++----
>  1 file changed, 7 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
> index e147087198ef..b825a5639afc 100644
> --- a/drivers/iommu/arm-smmu-v3.c
> +++ b/drivers/iommu/arm-smmu-v3.c
> @@ -2301,8 +2301,15 @@ static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
>  	cfg->cd.ttbr	= pgtbl_cfg->arm_lpae_s1_cfg.ttbr[0];
>  	cfg->cd.tcr	= pgtbl_cfg->arm_lpae_s1_cfg.tcr;
>  	cfg->cd.mair	= pgtbl_cfg->arm_lpae_s1_cfg.mair;
> +
> +	ret = arm_smmu_write_ctx_desc(smmu_domain, 0, &cfg->cd);

Hmm. This ends up calling arm_smmu_sync_cd() but I think that happens before
we've added the master to the devices list of the domain. Does that mean we
miss the new SSID during the invalidation?

> +	if (ret)
> +		goto out_free_tables;
> +
>  	return 0;
>  
> +out_free_tables:

nit: We have more tables in this driver than you can shake a stick at, so
please rename the label "out_free_cd_tables" or something like that.

Will