[PATCH v2 17/17] iommu/arm-smmu-v3: Add arm_smmu_cache_invalidate_user

[Nicolin Chen]

Add arm_smmu_cache_invalidate_user() function for user space to invalidate
TLB entries and Context Descriptors, since either an IO page table entrie
or a Context Descriptor in the user space is still cached by the hardware.

The input user_data is defined in struct iommu_hwpt_invalidate_arm_smmuv3,
which contains the essential info of the command queue of the guest OS. It
will be read by the host kernel to have a direct access to the guest queue
to fetch all invalidation commands. Those commands should be also fixed at
the SID and VMID fields by replacing with the correct physical values.

Co-developed-by: Eric Auger <eric.auger at redhat.com>
Signed-off-by: Eric Auger <eric.auger at redhat.com>
Signed-off-by: Nicolin Chen <nicolinc at nvidia.com>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 113 ++++++++++++++++++++
 1 file changed, 113 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 3902dd8cfcfa..124f63fe52e1 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2994,10 +2994,123 @@ static void arm_smmu_remove_dev_pasid(struct device *dev, ioasid_t pasid)
 	arm_smmu_sva_remove_dev_pasid(domain, dev, pasid);
 }
 
+static int arm_smmu_fix_user_cmd(struct arm_smmu_domain *smmu_domain, u64 *cmd)
+{
+	struct arm_smmu_stream *stream;
+
+	switch (*cmd & CMDQ_0_OP) {
+	case CMDQ_OP_TLBI_NSNH_ALL:
+		*cmd &= ~CMDQ_0_OP;
+		*cmd |= CMDQ_OP_TLBI_NH_ALL;
+		fallthrough;
+	case CMDQ_OP_TLBI_NH_VA:
+	case CMDQ_OP_TLBI_NH_VAA:
+	case CMDQ_OP_TLBI_NH_ALL:
+	case CMDQ_OP_TLBI_NH_ASID:
+		*cmd &= ~CMDQ_TLBI_0_VMID;
+		*cmd |= FIELD_PREP(CMDQ_TLBI_0_VMID,
+				   smmu_domain->s2->s2_cfg.vmid);
+		break;
+	case CMDQ_OP_ATC_INV:
+	case CMDQ_OP_CFGI_CD:
+	case CMDQ_OP_CFGI_CD_ALL:
+		xa_lock(&smmu_domain->smmu->streams_user);
+		stream = xa_load(&smmu_domain->smmu->streams_user,
+				 FIELD_GET(CMDQ_CFGI_0_SID, *cmd));
+		xa_unlock(&smmu_domain->smmu->streams_user);
+		if (!stream)
+			return -ENODEV;
+		*cmd &= ~CMDQ_CFGI_0_SID;
+		*cmd |= FIELD_PREP(CMDQ_CFGI_0_SID, stream->id);
+		break;
+	default:
+		return -EOPNOTSUPP;
+	}
+	pr_debug("Fixed user CMD: %016llx : %016llx\n", cmd[1], cmd[0]);
+
+	return 0;
+}
+
+static int arm_smmu_cache_invalidate_user(struct iommu_domain *domain,
+					   void *user_data)
+{
+	const u32 cons_err = FIELD_PREP(CMDQ_CONS_ERR, CMDQ_ERR_CERROR_ILL_IDX);
+	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
+	struct iommu_hwpt_invalidate_arm_smmuv3 *inv = user_data;
+	struct arm_smmu_device *smmu = smmu_domain->smmu;
+	struct arm_smmu_queue q = {
+		.llq = {
+			.prod = inv->cmdq_prod,
+			.max_n_shift = inv->cmdq_log2size,
+		},
+		.base = u64_to_user_ptr(inv->cmdq_uptr),
+		.ent_dwords = inv->cmdq_entry_size / sizeof(u64),
+	};
+	unsigned int nents = 1 << q.llq.max_n_shift;
+	void __user *cons_uptr;
+	int ncmds, i = 0;
+	u32 prod, cons;
+	u64 *cmds;
+	int ret;
+
+	if (!smmu || !smmu_domain->s2 || domain->type != IOMMU_DOMAIN_NESTED)
+		return -EINVAL;
+	if (q.ent_dwords != CMDQ_ENT_DWORDS)
+		return -EINVAL;
+	WARN_ON(q.llq.max_n_shift > smmu->cmdq.q.llq.max_n_shift);
+
+	cons_uptr = u64_to_user_ptr(inv->cmdq_cons_uptr);
+	if (copy_from_user(&q.llq.cons, cons_uptr, sizeof(u32)))
+		return -EFAULT;
+	if (queue_empty(&q.llq))
+		return -EINVAL;
+
+	prod = Q_IDX(&q.llq, q.llq.prod);
+	cons = Q_IDX(&q.llq, q.llq.cons);
+	if (Q_WRP(&q.llq, q.llq.prod) == Q_WRP(&q.llq, q.llq.cons))
+		ncmds = prod - cons;
+	else
+		ncmds = nents - cons + prod;
+	cmds = kcalloc(ncmds, inv->cmdq_entry_size, GFP_KERNEL);
+	if (!cmds)
+		return -ENOMEM;
+
+	do {
+		u64 *cmd = &cmds[i * CMDQ_ENT_DWORDS];
+
+		ret = copy_from_user(cmd, Q_ENT(&q, q.llq.cons),
+				     inv->cmdq_entry_size);
+		if (ret) {
+			ret = -EFAULT;
+			goto out_free_cmds;
+		}
+
+		ret = arm_smmu_fix_user_cmd(smmu_domain, cmd);
+		if (ret && ret != -EOPNOTSUPP) {
+			q.llq.cons |= cons_err;
+			goto out_copy_cons;
+		}
+		if (!ret)
+			i++;
+		queue_inc_cons(&q.llq);
+	} while (!queue_empty(&q.llq));
+
+	ret = arm_smmu_cmdq_issue_cmdlist(smmu, cmds, i, true);
+out_copy_cons:
+	if (copy_to_user(cons_uptr, &q.llq.cons, sizeof(u32)))
+		ret = -EFAULT;
+out_free_cmds:
+	kfree(cmds);
+	return ret;
+}
+
 static const struct iommu_domain_ops arm_smmu_nested_domain_ops = {
 	.attach_dev		= arm_smmu_attach_dev,
 	.free			= arm_smmu_domain_free,
 	.get_msi_mapping_domain	= arm_smmu_get_msi_mapping_domain,
+	.cache_invalidate_user	= arm_smmu_cache_invalidate_user,
+	.cache_invalidate_user_data_len =
+		sizeof(struct iommu_hwpt_invalidate_arm_smmuv3),
 };
 
 /**
-- 
2.40.1