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

chenxiang (M)
2021-03-23T01:28:53Z

Hi Eric,

在 2021/3/22 17:05, Auger Eric 写道:
> Hi Chenxiang,
>
> On 3/22/21 7:40 AM, chenxiang (M) wrote:
>> 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?
> At the QEMU VFIO notifier level, when I fill the struct
> iommu_cache_invalidate_info, I currently miss the granule info, hence
> this weird choice of setting setting info->nb_granules is always 1 and
> info->granule_size = size. I think in arm_smmu_cache_invalidate() I need
> to convert this info back to a the leaf page size, in case the host does
> not support RIL. Just as it is done in __arm_smmu_tlb_inv_range if RIL
> is supported.
>
> Does it makes sense to you?

Yes, it makes sense to me.
I am glad to test them if the patchset are ready.

>
> Thank you for spotting the issue.
>
> Eric
>>>> 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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>>
>
> .