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

chenxiang (M)
2021-03-22T06:41:41Z

Hi Eric,

在 2021/3/20 1:36, Auger Eric 写道:
> 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.

Do you have any idea about this issue?

>>
>> 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 ;-)

ok

>> 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.

Great

>
> 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,
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