Re: [PATCH v7 14/23] iommu/smmuv3: Implement cache_invalidate

Robin Murphy
2019-05-13T14:01:08Z

On 13/05/2019 13:16, Auger Eric wrote:
> Hi Robin,
> On 5/8/19 5:01 PM, Robin Murphy wrote:
>> On 08/04/2019 13:19, Eric Auger wrote:
>>> Implement domain-selective and page-selective IOTLB invalidations.
>>>
>>> Signed-off-by: Eric Auger <eric.auger@redhat.com>
>>>
>>> ---
>>> 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-smmu-v3.c | 60 +++++++++++++++++++++++++++++++++++++
>>>   1 file changed, 60 insertions(+)
>>>
>>> diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
>>> index 1486baf53425..4366921d8318 100644
>>> --- a/drivers/iommu/arm-smmu-v3.c
>>> +++ b/drivers/iommu/arm-smmu-v3.c
>>> @@ -2326,6 +2326,65 @@ 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_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_IOTLB) {
>>> +        if (inv_info->granularity == IOMMU_INV_GRANU_PASID) {
>>> +            struct arm_smmu_cmdq_ent cmd = {
>>> +                .opcode = CMDQ_OP_TLBI_NH_ASID,
>>> +                .tlbi = {
>>> +                    .vmid = smmu_domain->s2_cfg.vmid,
>>> +                    .asid = inv_info->pasid,
>>> +                },
>>> +            };
>>> +
>>> +            arm_smmu_cmdq_issue_cmd(smmu, &cmd);
>>> +            arm_smmu_cmdq_issue_sync(smmu);
>>
>> I'd much rather make arm_smmu_tlb_inv_context() understand nested
>> domains than open-code commands all over the place.
>
>
>>
>>> +
>>> +        } else if (inv_info->granularity == IOMMU_INV_GRANU_ADDR) {
>>> +            struct iommu_inv_addr_info *info = &inv_info->addr_info;
>>> +            size_t size = info->nb_granules * info->granule_size;
>>> +            bool leaf = info->flags & IOMMU_INV_ADDR_FLAGS_LEAF;
>>> +            struct arm_smmu_cmdq_ent cmd = {
>>> +                .opcode = CMDQ_OP_TLBI_NH_VA,
>>> +                .tlbi = {
>>> +                    .addr = info->addr,
>>> +                    .vmid = smmu_domain->s2_cfg.vmid,
>>> +                    .asid = info->pasid,
>>> +                    .leaf = leaf,
>>> +                },
>>> +            };
>>> +
>>> +            do {
>>> +                arm_smmu_cmdq_issue_cmd(smmu, &cmd);
>>> +                cmd.tlbi.addr += info->granule_size;
>>> +            } while (size -= info->granule_size);
>>> +            arm_smmu_cmdq_issue_sync(smmu);
>>
>> An this in particular I would really like to go all the way through
>> io_pgtable_tlb_add_flush()/io_pgtable_sync() if at all possible. Hooking
>> up range-based invalidations is going to be a massive headache if the
>> abstraction isn't solid.
>
> The concern is the host does not "own" the s1 config asid
> (smmu_domain->s1_cfg.cd.asid is not set, practically). In our case the
> asid only is passed by the userspace on CACHE_INVALIDATE ioctl call.
>
> arm_smmu_tlb_inv_context and arm_smmu_tlb_inv_range_nosync use this field

Right, but that's not exactly hard to solve. Even just something like
the (untested, purely illustrative) refactoring below would be beneficial.

Robin.

----->8-----
diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index d3880010c6cf..31ef703cf671 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -1423,11 +1423,9 @@ static void arm_smmu_tlb_inv_context(void *cookie)
arm_smmu_cmdq_issue_sync(smmu);
}

-static void arm_smmu_tlb_inv_range_nosync(unsigned long iova, size_t size,
- size_t granule, bool leaf, void *cookie)
+static void __arm_smmu_tlb_inv_range(struct arm_smmu_domain
*smmu_domain, u16 asid,
+ unsigned long iova, size_t size, size_t granule, bool leaf)
{
- struct arm_smmu_domain *smmu_domain = cookie;
- struct arm_smmu_device *smmu = smmu_domain->smmu;
struct arm_smmu_cmdq_ent cmd = {
.tlbi = {
.leaf = leaf,
@@ -1437,18 +1435,27 @@ static void
arm_smmu_tlb_inv_range_nosync(unsigned long iova, size_t size,

if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
cmd.opcode = CMDQ_OP_TLBI_NH_VA;
- cmd.tlbi.asid = smmu_domain->s1_cfg.cd.asid;
+ cmd.tlbi.asid = asid;
} else {
cmd.opcode = CMDQ_OP_TLBI_S2_IPA;
cmd.tlbi.vmid = smmu_domain->s2_cfg.vmid;
}

do {
- arm_smmu_cmdq_issue_cmd(smmu, &cmd);
+ arm_smmu_cmdq_issue_cmd(smmu_domain->smmu, &cmd);
cmd.tlbi.addr += granule;
} while (size -= granule);
}

+static void arm_smmu_tlb_inv_range_nosync(unsigned long iova, size_t size,
+ size_t granule, bool leaf, void *cookie)
+{
+ struct arm_smmu_domain *smmu_domain = cookie;
+
+ __arm_smmu_tlb_inv_range(smmu_domain, smmu_domain->s1_cfg.cd.asid, iova,
+ size, granule, leaf);
+}
+
static const struct iommu_gather_ops arm_smmu_gather_ops = {
.tlb_flush_all = arm_smmu_tlb_inv_context,
.tlb_add_flush = arm_smmu_tlb_inv_range_nosync,