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

chenxiang (M)
2021-03-04T07:56:17Z

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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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