Re: [PATCH v14 07/13] iommu/smmuv3: Implement cache_invalidate

[Auger Eric <eric.auger@redhat.com>]

Hi Chenxiang,

On 3/4/21 8:55 AM, chenxiang (M) wrote:
> Hi Eric,
> 
> 
> 在 2021/2/24 4:56, Eric Auger 写道:
>> Implement domain-selective, pasid selective and page-selective
>> IOTLB invalidations.
>>
>> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>>
>> ---
>>
>> v13 -> v14:
>> - Add domain invalidation
>> - do global inval when asid is not provided with addr
>>   granularity
>>
>> v7 -> v8:
>> - ASID based invalidation using iommu_inv_pasid_info
>> - check ARCHID/PASID flags in addr based invalidation
>> - use __arm_smmu_tlb_inv_context and __arm_smmu_tlb_inv_range_nosync
>>
>> v6 -> v7
>> - check the uapi version
>>
>> v3 -> v4:
>> - adapt to changes in the uapi
>> - add support for leaf parameter
>> - do not use arm_smmu_tlb_inv_range_nosync or arm_smmu_tlb_inv_context
>>   anymore
>>
>> v2 -> v3:
>> - replace __arm_smmu_tlb_sync by arm_smmu_cmdq_issue_sync
>>
>> v1 -> v2:
>> - properly pass the asid
>> ---
>>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 74 +++++++++++++++++++++
>>  1 file changed, 74 insertions(+)
>>
>> 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 4c19a1114de4..df3adc49111c 100644
>> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
>> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
>> @@ -2949,6 +2949,79 @@ static void arm_smmu_detach_pasid_table(struct iommu_domain *domain)
>>  	mutex_unlock(&smmu_domain->init_mutex);
>>  }
>>  
>> +static int
>> +arm_smmu_cache_invalidate(struct iommu_domain *domain, struct device *dev,
>> +			  struct iommu_cache_invalidate_info *inv_info)
>> +{
>> +	struct arm_smmu_cmdq_ent cmd = {.opcode = CMDQ_OP_TLBI_NSNH_ALL};
>> +	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
>> +	struct arm_smmu_device *smmu = smmu_domain->smmu;
>> +
>> +	if (smmu_domain->stage != ARM_SMMU_DOMAIN_NESTED)
>> +		return -EINVAL;
>> +
>> +	if (!smmu)
>> +		return -EINVAL;
>> +
>> +	if (inv_info->version != IOMMU_CACHE_INVALIDATE_INFO_VERSION_1)
>> +		return -EINVAL;
>> +
>> +	if (inv_info->cache & IOMMU_CACHE_INV_TYPE_PASID ||
>> +	    inv_info->cache & IOMMU_CACHE_INV_TYPE_DEV_IOTLB) {
>> +		return -ENOENT;
>> +	}
>> +
>> +	if (!(inv_info->cache & IOMMU_CACHE_INV_TYPE_IOTLB))
>> +		return -EINVAL;
>> +
>> +	/* IOTLB invalidation */
>> +
>> +	switch (inv_info->granularity) {
>> +	case IOMMU_INV_GRANU_PASID:
>> +	{
>> +		struct iommu_inv_pasid_info *info =
>> +			&inv_info->granu.pasid_info;
>> +
>> +		if (info->flags & IOMMU_INV_ADDR_FLAGS_PASID)
>> +			return -ENOENT;
>> +		if (!(info->flags & IOMMU_INV_PASID_FLAGS_ARCHID))
>> +			return -EINVAL;
>> +
>> +		__arm_smmu_tlb_inv_context(smmu_domain, info->archid);
>> +		return 0;
>> +	}
>> +	case IOMMU_INV_GRANU_ADDR:
>> +	{
>> +		struct iommu_inv_addr_info *info = &inv_info->granu.addr_info;
>> +		size_t size = info->nb_granules * info->granule_size;
>> +		bool leaf = info->flags & IOMMU_INV_ADDR_FLAGS_LEAF;
>> +
>> +		if (info->flags & IOMMU_INV_ADDR_FLAGS_PASID)
>> +			return -ENOENT;
>> +
>> +		if (!(info->flags & IOMMU_INV_ADDR_FLAGS_ARCHID))
>> +			break;
>> +
>> +		arm_smmu_tlb_inv_range_domain(info->addr, size,
>> +					      info->granule_size, leaf,
>> +					      info->archid, smmu_domain);
> 
> Is it possible to add a check before the function to make sure that
> info->granule_size can be recognized by SMMU?
> There is a scenario which will cause TLBI issue: RIL feature is enabled
> on guest but is disabled on host, and then on
> host it just invalidate 4K/2M/1G once a time, but from QEMU,
> info->nb_granules is always 1 and info->granule_size = size,
> if size is not equal to 4K or 2M or 1G (for example size = granule_size
> is 5M), it will only part of the size it wants to invalidate.
> 
> I think maybe we can add a check here: if RIL is not enabled and also
> size is not the granule_size (4K/2M/1G) supported by
> SMMU hardware, can we just simply use the smallest granule_size
> supported by hardware all the time?
> 
>> +
>> +		arm_smmu_cmdq_issue_sync(smmu);
>> +		return 0;
>> +	}
>> +	case IOMMU_INV_GRANU_DOMAIN:
>> +		break;
> 
> I check the qemu code
> (https://github.com/eauger/qemu/tree/v5.2.0-2stage-rfcv8), for opcode
> CMD_TLBI_NH_ALL or CMD_TLBI_NSNH_ALL from guest OS
> it calls smmu_inv_notifiers_all() to unamp all notifiers of all mr's,
> but it seems not set event.entry.granularity which i think it should set
> IOMMU_INV_GRAN_ADDR.
this is because IOMMU_INV_GRAN_ADDR = 0. But for clarity I should rather
set it explicitly ;-)
> BTW, for opcode CMD_TLBI_NH_ALL or CMD_TLBI_NSNH_ALL, it needs to unmap
> size = 0x1000000000000 on 48bit system (it may spend much time),  maybe
> it is better
> to set it as IOMMU_INV_GRANU_DOMAIN, then in host OS, send TLBI_NH_ALL
> directly when IOMMU_INV_GRANU_DOMAIN.
Yes you're right. If the host does not support RIL then it is an issue.
This is going to be fixed in the next version.

Thank you for the report!

Best Regards

Eric
> 
> 
>> +	default:
>> +		return -EINVAL;
>> +	}
>> +
>> +	/* Global S1 invalidation */
>> +	cmd.tlbi.vmid   = smmu_domain->s2_cfg.vmid;
>> +	arm_smmu_cmdq_issue_cmd(smmu, &cmd);
>> +	arm_smmu_cmdq_issue_sync(smmu);
>> +	return 0;
>> +}
>> +
>>  static bool arm_smmu_dev_has_feature(struct device *dev,
>>  				     enum iommu_dev_features feat)
>>  {
>> @@ -3048,6 +3121,7 @@ static struct iommu_ops arm_smmu_ops = {
>>  	.put_resv_regions	= generic_iommu_put_resv_regions,
>>  	.attach_pasid_table	= arm_smmu_attach_pasid_table,
>>  	.detach_pasid_table	= arm_smmu_detach_pasid_table,
>> +	.cache_invalidate	= arm_smmu_cache_invalidate,
>>  	.dev_has_feat		= arm_smmu_dev_has_feature,
>>  	.dev_feat_enabled	= arm_smmu_dev_feature_enabled,
>>  	.dev_enable_feat	= arm_smmu_dev_enable_feature,
>