diff mbox

[v2,39/40] iommu/arm-smmu-v3: Add support for PRI

Message ID 20180511190641.23008-40-jean-philippe.brucker@arm.com (mailing list archive)
State New, archived
Delegated to: Bjorn Helgaas
Headers show

Commit Message

Jean-Philippe Brucker May 11, 2018, 7:06 p.m. UTC
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: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>

---
v1->v2:
* Terminate the page request and disable PRI if no handler is registered
* Enable and disable PRI in sva_device_init/shutdown, instead of
  add/remove_device
---
 drivers/iommu/arm-smmu-v3.c | 192 +++++++++++++++++++++++++++---------
 1 file changed, 145 insertions(+), 47 deletions(-)

Comments

Bharat Kumar Gogada May 25, 2018, 2:08 p.m. UTC | #1
> 
> 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: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
> 
> ---
> v1->v2:
> * Terminate the page request and disable PRI if no handler is registered
> * Enable and disable PRI in sva_device_init/shutdown, instead of
>   add/remove_device
> ---
>  drivers/iommu/arm-smmu-v3.c | 192 +++++++++++++++++++++++++++-------
> --
>  1 file changed, 145 insertions(+), 47 deletions(-)
> 
> diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
> index 6cb69ace371b..0edbb8d19579 100644
> --- a/drivers/iommu/arm-smmu-v3.c
> +++ b/drivers/iommu/arm-smmu-v3.c
> @@ -248,6 +248,7 @@
>  #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)
> @@ -309,6 +310,9 @@
>  #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)
> @@ -383,12 +387,6 @@ 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,
> @@ -471,7 +469,7 @@ 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
> @@ -556,6 +554,7 @@ 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 {
> @@ -907,14 +906,18 @@ 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); @@ -1114,8 +1117,15 @@ 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;
>  	}
> 
> @@ -1236,6 +1246,9 @@ 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)
> @@ -1471,39 +1484,54 @@ 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;
> -
> -	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]);
> -
> -	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,
> -			},
> +	u32 sid = FIELD_PREP(PRIQ_0_SID, evt[0]);
> +
> +	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,
> +	};
> +
> +	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);
>  	}
>  }
> 
> @@ -1529,6 +1557,11 @@ 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));
> 
> @@ -1577,7 +1610,8 @@ 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;
>  	}
> 
> @@ -2301,6 +2335,59 @@ 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, pos;
> +	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);

Any reason why this is not cleared in arm_smmu_disable_pri ?

> +
> +	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;
> @@ -2314,11 +2401,15 @@ 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)
> @@ -2329,11 +2420,17 @@ 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);
>  }
> 
> @@ -2671,6 +2768,7 @@ 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);
> --
> 2.17.0
Jean-Philippe Brucker May 29, 2018, 10:27 a.m. UTC | #2
On 25/05/18 15:08, Bharat Kumar Gogada wrote:
>> +	master->can_fault = true;
>> +	master->ste.prg_resp_needs_ssid =
>> pci_prg_resp_requires_prefix(pdev);
> 
> Any reason why this is not cleared in arm_smmu_disable_pri ?

Actually, setting it here is wrong. Since we now call enable_pri()
lazily, prg_resp_needs_ssid isn't initialized when writing the STE. That
bit is read by the SMMU when the PRIQ is full and it needs to
auto-respond. Fortunately the PRI doesn't need to be enabled in order to
read this bit, so we can move pci_prg_resp_requires_prefix() to
add_device() and clear the bit in remove_device(). Thanks for catching this.

Jean
diff mbox

Patch

diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index 6cb69ace371b..0edbb8d19579 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -248,6 +248,7 @@ 
 #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)
@@ -309,6 +310,9 @@ 
 #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)
@@ -383,12 +387,6 @@  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,
@@ -471,7 +469,7 @@  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
@@ -556,6 +554,7 @@  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 {
@@ -907,14 +906,18 @@  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);
@@ -1114,8 +1117,15 @@  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;
 	}
 
@@ -1236,6 +1246,9 @@  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)
@@ -1471,39 +1484,54 @@  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;
-
-	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]);
-
-	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,
-			},
+	u32 sid = FIELD_PREP(PRIQ_0_SID, evt[0]);
+
+	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,
+	};
+
+	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);
 	}
 }
 
@@ -1529,6 +1557,11 @@  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));
 
@@ -1577,7 +1610,8 @@  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;
 	}
 
@@ -2301,6 +2335,59 @@  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, pos;
+	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;
@@ -2314,11 +2401,15 @@  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)
@@ -2329,11 +2420,17 @@  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);
 }
 
@@ -2671,6 +2768,7 @@  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);