On 22.07.19 11:51, Lokesh Vutla wrote:
>>> +static int arm_smmu_init_strtab_2lvl(struct arm_smmu_device *smmu)
>>> +{
>>> + struct arm_smmu_strtab_cfg *cfg = &smmu->strtab_cfg;
>>> + u32 size, l1size;
>>> + void *strtab;
>>> + u64 reg;
>>> + int ret;
>>> +
>>> + /* Calculate the L1 size, capped to the SIDSIZE. */
>>> + size = STRTAB_L1_SZ_SHIFT - 3;
>>> + size = MIN(size, smmu->sid_bits - STRTAB_SPLIT);
>>> + cfg->num_l1_ents = 1 << size;
>>> +
>>> + size += STRTAB_SPLIT;
>>> + if (size < smmu->sid_bits)
>>> + printk("WARN: SMMU 2-level strtab only covers %u/%u bits of
>>> SID\n",
>>> + size, smmu->sid_bits);
>>
>> What does that mean for the user? Or the guest?
>
> This specfies that the driver does not support all the stream ids that
> hardware
> specifies that are supported. Driver supports for 25 sid bits(with 128K L1
> entries and 256L2 entries). I don't think there would be any realistic use
> case
> using a stream id with > 25 bits.
>
OK. Maybe worth clarify this in form of a comment.
[...]
>>> +
>>> +static int arm_smmuv3_cell_init(struct cell *cell)
>>> +{
>>> + struct jailhouse_iommu *iommu;
>>> + struct arm_smmu_cmdq_ent cmd;
>>> + int ret, i, j, sid;
>>> +
>>> + for (i = 0; i < JAILHOUSE_MAX_IOMMU_UNITS; i++) {
>>> + iommu = &system_config->platform_info.arm.iommu_units[i];
>>> + if (iommu->type != JAILHOUSE_IOMMU_SMMUV3)
>>> + continue;
>>> +
>>> + for_each_stream_id(sid, cell->config, j) {
>>> + ret = arm_smmu_init_ste(&smmu[i], sid,
>>> cell->config->id);
>>> + if (ret) {
>>> + printk("ERROR: SMMU INIT ste failed: sid =
>>> %d\n",
>>> + sid);
>>> + return ret;
>>
>> Do we need any rollback in case only one of many calls fails?
>
> I don't think so, as that specific stream id will not be supported and rest
> can
> work as is. Do you see other reason for roll back?
I didn't look into details, if arm_smmu_init_ste leaves anything rollback-worthy
behind, was just asking this question openly to make you check that again.
Jan
--
Siemens AG, Corporate Technology, CT RDA IOT SES-DE
Corporate Competence Center Embedded Linux
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