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

["chenxiang (M)" <chenxiang66@xxxxxxxxxxxxx>]

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@xxxxxxxxxx>

---

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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