[PATCH v5 10/15] iommu/arm-smmu-v3: Support PRI Page Request in arm_smmu_handle_ppr()

[Nicolin Chen]

For a PRI-enabled master, convert every PRIQ entry into an iopf_fault and
report it through iommu_report_device_fault().

For an unknown StreamID or a master without PRI enabled, keep the existing
LAST-page DENY path. Merge its two messages into one ratelimited line so a
faulty device cannot flood the kernel log.

Discard any PASID Stop Marker (LRW = 0b100) prior to the fault report and
the DENY fallback both, because a Stop Marker does not expect a response.
The IOPF infrastructure requires the driver to discard it, as per the doc
at iommu_report_device_fault(). This also matches the intel-iommu code.

When SSV is clear, the same LRW encoding is a PRI Page Request that expects
a response, so let it fall through.

Note that master->pri_enabled will only be set by a later change, once all
the PRI paths are ready.

Co-developed-by: Barak Biber <bbiber@xxxxxxxxxx>
Signed-off-by: Barak Biber <bbiber@xxxxxxxxxx>
Co-developed-by: Stefan Kaestle <skaestle@xxxxxxxxxx>
Signed-off-by: Stefan Kaestle <skaestle@xxxxxxxxxx>
Signed-off-by: Malak Marrid <mmarrid@xxxxxxxxxx>
Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 50 +++++++++++++++++++--
 1 file changed, 47 insertions(+), 3 deletions(-)

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 40ea5bd382d89..17ca3fcd1b9c0 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2378,6 +2378,7 @@ static irqreturn_t arm_smmu_evtq_thread(int irq, void *dev)
 
 static void arm_smmu_handle_ppr(struct arm_smmu_device *smmu, u64 *evt)
 {
+	struct arm_smmu_master *master;
 	u32 sid, ssid;
 	u16 grpid;
 	bool ssv, last;
@@ -2388,9 +2389,52 @@ static void arm_smmu_handle_ppr(struct arm_smmu_device *smmu, u64 *evt)
 	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",
+	/*
+	 * A PASID Stop Marker (LRW = 0b100) does not expect a response and
+	 * must be discarded before fault reporting: see the documentation
+	 * at iommu_report_device_fault().
+	 *
+	 * Gate it on SSV, as without a PASID that same encoding is a PRI Page
+	 * Request and it does expect a response. So let it fall through and be
+	 * answered with a PRI_RESP_FAIL, since iommu_sva_handle_mm() rejects a
+	 * PASID-less fault, or by the PRI_RESP_DENY issued below.
+	 */
+	if (last && ssv && !(evt[0] & (PRIQ_0_PERM_READ | PRIQ_0_PERM_WRITE)))
+		return;
+
+	mutex_lock(&smmu->streams_mutex);
+	master = arm_smmu_find_master(smmu, sid);
+	if (master && master->pri_enabled) {
+		struct iopf_fault iopf_fault = {};
+		struct iommu_fault *fault = &iopf_fault.fault;
+
+		fault->type = IOMMU_FAULT_PAGE_REQ;
+		if (last)
+			fault->prm.flags |= IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE;
+		if (ssv) {
+			fault->prm.flags |=
+				IOMMU_FAULT_PAGE_REQUEST_PASID_VALID;
+			fault->prm.pasid = ssid;
+		}
+		fault->prm.grpid = grpid;
+		if (evt[0] & PRIQ_0_PERM_READ)
+			fault->prm.perm |= IOMMU_FAULT_PERM_READ;
+		if (evt[0] & PRIQ_0_PERM_WRITE)
+			fault->prm.perm |= IOMMU_FAULT_PERM_WRITE;
+		if (evt[0] & PRIQ_0_PERM_EXEC)
+			fault->prm.perm |= IOMMU_FAULT_PERM_EXEC;
+		if (evt[0] & PRIQ_0_PERM_PRIV)
+			fault->prm.perm |= IOMMU_FAULT_PERM_PRIV;
+		fault->prm.addr = FIELD_GET(PRIQ_1_ADDR_MASK, evt[1]) << 12;
+
+		iommu_report_device_fault(master->dev, &iopf_fault);
+		mutex_unlock(&smmu->streams_mutex);
+		return;
+	}
+	mutex_unlock(&smmu->streams_mutex);
+
+	dev_info_ratelimited(smmu->dev,
+		 "unexpected PRI request: sid 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" : "",
-- 
2.43.0