iommu/arm-smmu-v3: Add support for PRI

hulk inclusion
category: feature
bugzilla: 14369
CVE: NA
-------------------

For PCI devices that support it, enable the PRI capability and handle PRI
Page Requests with the generic fault handler. It is enabled on demand by
iommu_sva_device_init().
Signed-off-by: NJean-Philippe Brucker <jean-philippe.brucker@arm.com>
Signed-off-by: NFang Lijun <fanglijun3@huawei.com>
Reviewed-by: NHanjun Guo <guohanjun@huawei.com>
Reviewed-by: NZhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

drivers/iommu/arm-smmu-v3.c

@@ -251,6 +251,7 @@
 #define STRTAB_STE_1_S1COR		GENMASK_ULL(5, 4)
 #define STRTAB_STE_1_S1CSH		GENMASK_ULL(7, 6)
 
+#define STRTAB_STE_1_PPAR		(1UL << 18)
 #define STRTAB_STE_1_S1STALLD		(1UL << 27)
 
 #define STRTAB_STE_1_EATS		GENMASK_ULL(29, 28)
@@ -312,6 +313,9 @@
 #define CMDQ_PRI_0_SID			GENMASK_ULL(63, 32)
 #define CMDQ_PRI_1_GRPID		GENMASK_ULL(8, 0)
 #define CMDQ_PRI_1_RESP			GENMASK_ULL(13, 12)
+#define CMDQ_PRI_1_RESP_FAILURE		FIELD_PREP(CMDQ_PRI_1_RESP, 0UL)
+#define CMDQ_PRI_1_RESP_INVALID		FIELD_PREP(CMDQ_PRI_1_RESP, 1UL)
+#define CMDQ_PRI_1_RESP_SUCCESS		FIELD_PREP(CMDQ_PRI_1_RESP, 2UL)
 
 #define CMDQ_RESUME_0_SID		GENMASK_ULL(63, 32)
 #define CMDQ_RESUME_0_ACTION_RETRY	(1UL << 12)
@@ -387,12 +391,6 @@ module_param_named(disable_ats_check, disable_ats_check, bool, S_IRUGO);
 MODULE_PARM_DESC(disable_ats_check,
 	"By default, the SMMU checks whether each incoming transaction marked as translated is allowed by the stream configuration. This option disables the check.");
 
-enum pri_resp {
-	PRI_RESP_DENY = 0,
-	PRI_RESP_FAIL = 1,
-	PRI_RESP_SUCC = 2,
-};
-
 enum arm_smmu_msi_index {
 	EVTQ_MSI_INDEX,
 	GERROR_MSI_INDEX,
@@ -475,7 +473,7 @@ struct arm_smmu_cmdq_ent {
 			u32			sid;
 			u32			ssid;
 			u16			grpid;
-			enum pri_resp		resp;
+			enum page_response_code	resp;
 		} pri;
 
 		#define CMDQ_OP_RESUME		0x44
@@ -560,6 +558,7 @@ struct arm_smmu_strtab_ent {
 	struct arm_smmu_s2_cfg		*s2_cfg;
 
 	bool				can_stall;
+	bool				prg_resp_needs_ssid;
 };
 
 struct arm_smmu_strtab_cfg {
@@ -936,14 +935,18 @@ static int arm_smmu_cmdq_build_cmd(u64 *cmd, struct arm_smmu_cmdq_ent *ent)
 		cmd[0] |= FIELD_PREP(CMDQ_PRI_0_SID, ent->pri.sid);
 		cmd[1] |= FIELD_PREP(CMDQ_PRI_1_GRPID, ent->pri.grpid);
 		switch (ent->pri.resp) {
-		case PRI_RESP_DENY:
-		case PRI_RESP_FAIL:
-		case PRI_RESP_SUCC:
+		case IOMMU_PAGE_RESP_FAILURE:
+			cmd[1] |= CMDQ_PRI_1_RESP_FAILURE;
+			break;
+		case IOMMU_PAGE_RESP_INVALID:
+			cmd[1] |= CMDQ_PRI_1_RESP_INVALID;
+			break;
+		case IOMMU_PAGE_RESP_SUCCESS:
+			cmd[1] |= CMDQ_PRI_1_RESP_SUCCESS;
 			break;
 		default:
 			return -EINVAL;
 		}
-		cmd[1] |= FIELD_PREP(CMDQ_PRI_1_RESP, ent->pri.resp);
 		break;
 	case CMDQ_OP_RESUME:
 		cmd[0] |= FIELD_PREP(CMDQ_RESUME_0_SID, ent->resume.sid);
@@ -1157,8 +1160,15 @@ static int arm_smmu_page_response(struct device *dev,
 		cmd.resume.sid		= sid;
 		cmd.resume.stag		= resp->page_req_group_id;
 		cmd.resume.resp		= resp->resp_code;
+	} else if (master->can_fault) {
+		cmd.opcode		= CMDQ_OP_PRI_RESP;
+		cmd.substream_valid	= resp->pasid_present &&
+					  master->ste.prg_resp_needs_ssid;
+		cmd.pri.sid		= sid;
+		cmd.pri.ssid		= resp->pasid;
+		cmd.pri.grpid		= resp->page_req_group_id;
+		cmd.pri.resp		= resp->resp_code;
 	} else {
-		/* TODO: put PRI response here */
 		return -ENODEV;
 	}
 
@@ -1290,6 +1300,9 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_device *smmu, u32 sid,
 			 FIELD_PREP(STRTAB_STE_1_S1CSH, ARM_SMMU_SH_ISH) |
 			 FIELD_PREP(STRTAB_STE_1_STRW, strw));
 
+		if (ste->prg_resp_needs_ssid)
+			dst[1] |= STRTAB_STE_1_PPAR;
+
 		if (smmu->features & ARM_SMMU_FEAT_STALLS &&
 		   !(smmu->features & ARM_SMMU_FEAT_STALL_FORCE) &&
 		   !ste->can_stall)
@@ -1606,39 +1619,54 @@ static irqreturn_t arm_smmu_evtq_thread(int irq, void *dev)
 
 static void arm_smmu_handle_ppr(struct arm_smmu_device *smmu, u64 *evt)
 {
-	u32 sid, ssid;
-	u16 grpid;
-	bool ssv, last;
+	u32 sid = FIELD_PREP(PRIQ_0_SID, evt[0]);
 
-	sid = FIELD_GET(PRIQ_0_SID, evt[0]);
-	ssv = FIELD_GET(PRIQ_0_SSID_V, evt[0]);
-	ssid = ssv ? FIELD_GET(PRIQ_0_SSID, evt[0]) : 0;
-	last = FIELD_GET(PRIQ_0_PRG_LAST, evt[0]);
-	grpid = FIELD_GET(PRIQ_1_PRG_IDX, evt[1]);
+	struct arm_smmu_master_data *master;
+	struct iommu_fault_event fault = {
+		.type			= IOMMU_FAULT_PAGE_REQ,
+		.last_req		= FIELD_GET(PRIQ_0_PRG_LAST, evt[0]),
+		.pasid_valid		= FIELD_GET(PRIQ_0_SSID_V, evt[0]),
+		.pasid			= FIELD_GET(PRIQ_0_SSID, evt[0]),
+		.page_req_group_id	= FIELD_GET(PRIQ_1_PRG_IDX, evt[1]),
+		.addr			= evt[1] & PRIQ_1_ADDR_MASK,
+	};
 
-	dev_info(smmu->dev, "unexpected PRI request received:\n");
-	dev_info(smmu->dev,
-		 "\tsid 0x%08x.0x%05x: [%u%s] %sprivileged %s%s%s access at iova 0x%016llx\n",
-		 sid, ssid, grpid, last ? "L" : "",
-		 evt[0] & PRIQ_0_PERM_PRIV ? "" : "un",
-		 evt[0] & PRIQ_0_PERM_READ ? "R" : "",
-		 evt[0] & PRIQ_0_PERM_WRITE ? "W" : "",
-		 evt[0] & PRIQ_0_PERM_EXEC ? "X" : "",
-		 evt[1] & PRIQ_1_ADDR_MASK);
-
-	if (last) {
-		struct arm_smmu_cmdq_ent cmd = {
-			.opcode			= CMDQ_OP_PRI_RESP,
-			.substream_valid	= ssv,
-			.pri			= {
-				.sid	= sid,
-				.ssid	= ssid,
-				.grpid	= grpid,
-				.resp	= PRI_RESP_DENY,
-			},
+	if (evt[0] & PRIQ_0_PERM_READ)
+		fault.prot |= IOMMU_FAULT_READ;
+	if (evt[0] & PRIQ_0_PERM_WRITE)
+		fault.prot |= IOMMU_FAULT_WRITE;
+	if (evt[0] & PRIQ_0_PERM_EXEC)
+		fault.prot |= IOMMU_FAULT_EXEC;
+	if (evt[0] & PRIQ_0_PERM_PRIV)
+		fault.prot |= IOMMU_FAULT_PRIV;
+
+	/* Discard Stop PASID marker, it isn't used */
+	if (!(fault.prot & (IOMMU_FAULT_READ|IOMMU_FAULT_WRITE)) &&
+	    fault.last_req)
+		return;
+
+	master = arm_smmu_find_master(smmu, sid);
+	if (WARN_ON(!master))
+		return;
+
+	if (iommu_report_device_fault(master->dev, &fault)) {
+		/*
+		 * No handler registered, so subsequent faults won't produce
+		 * better results. Try to disable PRI.
+		 */
+		struct page_response_msg page_response = {
+			.addr			= fault.addr,
+			.pasid			= fault.pasid,
+			.pasid_present		= fault.pasid_valid,
+			.page_req_group_id	= fault.page_req_group_id,
+			.resp_code		= IOMMU_PAGE_RESP_FAILURE,
 		};
 
-		arm_smmu_cmdq_issue_cmd(smmu, &cmd);
+		dev_warn(master->dev,
+			 "PPR 0x%x:0x%llx 0x%x: nobody cared, disabling PRI\n",
+			 fault.pasid_valid ? fault.pasid : 0, fault.addr,
+			 fault.prot);
+		arm_smmu_page_response(master->dev, &page_response);
 	}
 }
 
@@ -1664,6 +1692,11 @@ static irqreturn_t arm_smmu_priq_thread(int irq, void *dev)
 		}
 
 		if (queue_sync_prod(q) == -EOVERFLOW)
+			/*
+			 * TODO: flush pending faults, since the SMMU might have
+			 * auto-responded to the Last request of a pending
+			 * group
+			 */
 			dev_err(smmu->dev, "PRIQ overflow detected -- requests lost\n");
 	} while (!queue_empty(q));
 
@@ -1714,7 +1747,8 @@ static int arm_smmu_flush_queues(void *cookie, struct device *dev)
 		master = dev->iommu_fwspec->iommu_priv;
 		if (master->ste.can_stall)
 			arm_smmu_flush_queue(smmu, &smmu->evtq.q, "evtq");
-		/* TODO: add support for PRI */
+		else if (master->can_fault)
+			arm_smmu_flush_queue(smmu, &smmu->priq.q, "priq");
 		return 0;
 	}
 
@@ -2456,6 +2490,59 @@ arm_smmu_iova_to_phys(struct iommu_domain *domain, dma_addr_t iova)
 	return ops->iova_to_phys(ops, iova);
 }
 
+static int arm_smmu_enable_pri(struct arm_smmu_master_data *master)
+{
+	int ret;
+	struct pci_dev *pdev;
+	/*
+	 * TODO: find a good inflight PPR number. We should divide the PRI queue
+	 * by the number of PRI-capable devices, but it's impossible to know
+	 * about current and future (hotplugged) devices. So we're at risk of
+	 * dropping PPRs (and leaking pending requests in the FQ).
+	 */
+	size_t max_inflight_pprs = 16;
+	struct arm_smmu_device *smmu = master->smmu;
+
+	if (!(smmu->features & ARM_SMMU_FEAT_PRI) || !dev_is_pci(master->dev))
+		return -ENOSYS;
+
+	pdev = to_pci_dev(master->dev);
+
+	ret = pci_reset_pri(pdev);
+	if (ret)
+		return ret;
+
+	ret = pci_enable_pri(pdev, max_inflight_pprs);
+	if (ret) {
+		dev_err(master->dev, "cannot enable PRI: %d\n", ret);
+		return ret;
+	}
+
+	master->can_fault = true;
+	master->ste.prg_resp_needs_ssid = pci_prg_resp_requires_prefix(pdev);
+
+	dev_dbg(master->dev, "enabled PRI\n");
+
+	return 0;
+}
+
+static void arm_smmu_disable_pri(struct arm_smmu_master_data *master)
+{
+	struct pci_dev *pdev;
+
+	if (!dev_is_pci(master->dev))
+		return;
+
+	pdev = to_pci_dev(master->dev);
+
+	if (!pdev->pri_enabled)
+		return;
+
+	pci_disable_pri(pdev);
+	dev_dbg(master->dev, "disabled PRI\n");
+	master->can_fault = false;
+}
+
 static int arm_smmu_sva_init(struct device *dev, struct iommu_sva_param *param)
 {
 	int ret;
@@ -2469,11 +2556,15 @@ static int arm_smmu_sva_init(struct device *dev, struct iommu_sva_param *param)
 		return -EINVAL;
 
 	if (param->features & IOMMU_SVA_FEAT_IOPF) {
-		if (!master->can_fault)
-			return -EINVAL;
+		arm_smmu_enable_pri(master);
+		if (!master->can_fault) {
+			ret = -ENODEV;
+			goto err_disable_pri;
+		}
+
 		ret = iopf_queue_add_device(master->smmu->iopf_queue, dev);
 		if (ret)
-			return ret;
+			goto err_disable_pri;
 	}
 
 	if (!param->max_pasid)
@@ -2484,11 +2575,17 @@ static int arm_smmu_sva_init(struct device *dev, struct iommu_sva_param *param)
 	param->max_pasid = min(param->max_pasid, (1U << master->ssid_bits) - 1);
 
 	return 0;
+
+err_disable_pri:
+	arm_smmu_disable_pri(master);
+
+	return ret;
 }
 
 static void arm_smmu_sva_shutdown(struct device *dev,
 				  struct iommu_sva_param *param)
 {
+	arm_smmu_disable_pri(dev->iommu_fwspec->iommu_priv);
 	iopf_queue_remove_device(dev);
 }
 
@@ -2826,6 +2923,7 @@ static void arm_smmu_remove_device(struct device *dev)
 	iommu_group_remove_device(dev);
 	arm_smmu_remove_master(smmu, master);
 	iommu_device_unlink(&smmu->iommu, dev);
+	arm_smmu_disable_pri(master);
 	arm_smmu_disable_ats(master);
 	kfree(master);
 	iommu_fwspec_free(dev);