[PATCH 3/5] iommu/amd: Fix missing CMD_COMPLETE_PPR response for invalid PPR requests

[Vasant Hegde <vasant.hegde@amd.com>]

The AMD IOMMU spec, requires the host to respond with a CMD_COMPLETE_PPR
command when an EVENT_TYPE_INV_PPR_REQ event is received with the RX bit
cleared. This response was missing in the current implementation, leaving
invalid PPR requests unacknowledged.

Introduce amd_iommu_report_ppr_err() to handle EVENT_TYPE_INV_PPR_REQ
events. The new function logs the invalid PPR request and when the RX
bit is cleared, sends CMD_COMPLETE_PPR response.

Reported-by: Gaultier Delbarre <Gaultier.Delbarre@amd.com>
Co-developed-by: Wei Huang <wei.huang2@amd.com>
Signed-off-by: Wei Huang <wei.huang2@amd.com>
Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
---
 drivers/iommu/amd/amd_iommu_types.h |  1 +
 drivers/iommu/amd/iommu.c           | 38 ++++++++++++++++++++++++-----
 2 files changed, 33 insertions(+), 6 deletions(-)

diff --git a/drivers/iommu/amd/amd_iommu_types.h b/drivers/iommu/amd/amd_iommu_types.h
index a7aa9411b2e9..500952e752b4 100644
--- a/drivers/iommu/amd/amd_iommu_types.h
+++ b/drivers/iommu/amd/amd_iommu_types.h
@@ -159,6 +159,7 @@
 #define EVENT_FLAGS_SHIFT	0x10
 #define EVENT_FLAG_RW		0x020
 #define EVENT_FLAG_I		0x008
+#define EVENT_FLAG_PPR_RX	0x001
 
 /* feature control bits */
 #define CONTROL_IOMMU_EN	0
diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index 563f9c2672d5..4372d3908e67 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -905,10 +905,40 @@ static void amd_iommu_report_page_fault(struct amd_iommu *iommu,
 		pci_dev_put(pdev);
 }
 
+static void amd_iommu_report_ppr_err(struct amd_iommu *iommu, volatile u32 *event,
+				     u16 devid, u64 address, int flags)
+{
+	struct pci_dev *pdev;
+	struct device *dev = iommu->iommu.dev;
+	u32 pasid = PPR_PASID(*((u64 *)event));
+	int tag = event[1] & 0x03FF;
+
+	dev_err(dev, "Event logged [INVALID_PPR_REQUEST device=%04x:%02x:%02x.%x pasid=0x%05x address=0x%llx flags=0x%04x tag=0x%03x]\n",
+		iommu->pci_seg->id, PCI_BUS_NUM(devid), PCI_SLOT(devid), PCI_FUNC(devid),
+		pasid, address, flags, tag);
+
+	/* Skip COMPLETE_PPR_REQUEST response if RX=1 */
+	if (flags & EVENT_FLAG_PPR_RX)
+		return;
+
+	pdev = pci_get_domain_bus_and_slot(iommu->pci_seg->id, PCI_BUS_NUM(devid),
+					   devid & 0xff);
+	if (!pdev)
+		return;
+
+	if (!dev_iommu_priv_get(&pdev->dev)) {
+		pci_dev_put(pdev);
+		return;
+	}
+
+	amd_iommu_complete_ppr(&pdev->dev, pasid, IOMMU_PAGE_RESP_FAILURE, tag);
+	pci_dev_put(pdev);
+}
+
 static void iommu_print_event(struct amd_iommu *iommu, void *__evt)
 {
 	struct device *dev = iommu->iommu.dev;
-	int type, devid, flags, tag;
+	int type, devid, flags;
 	volatile u32 *event = __evt;
 	int count = 0;
 	u64 address, ctrl;
@@ -982,11 +1012,7 @@ static void iommu_print_event(struct amd_iommu *iommu, void *__evt)
 		amd_iommu_report_rmp_hw_error(iommu, event);
 		break;
 	case EVENT_TYPE_INV_PPR_REQ:
-		pasid = PPR_PASID(*((u64 *)__evt));
-		tag = event[1] & 0x03FF;
-		dev_err(dev, "Event logged [INVALID_PPR_REQUEST device=%04x:%02x:%02x.%x pasid=0x%05x address=0x%llx flags=0x%04x tag=0x%03x]\n",
-			iommu->pci_seg->id, PCI_BUS_NUM(devid), PCI_SLOT(devid), PCI_FUNC(devid),
-			pasid, address, flags, tag);
+		amd_iommu_report_ppr_err(iommu, event, devid, address, flags);
 		break;
 	default:
 		dev_err(dev, "Event logged [UNKNOWN event[0]=0x%08x event[1]=0x%08x event[2]=0x%08x event[3]=0x%08x\n",
-- 
2.31.1