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

["chenxiang (M)" <chenxiang66@hisilicon.com>]

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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.
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.


> +	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,


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