[PATCH v2 07/16] iommu/vt-d: assign PFSID in device TLB invalidation

[Jacob Pan]

When SRIOV VF device IOTLB is invalidated, we need to provide
the PF source SID such that IOMMU hardware can gauge the depth
of invalidation queue which is shared among VFs. This is needed
when device invalidation throttle (DIT) capability is supported.

Signed-off-by: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
---
 drivers/iommu/intel-iommu.c | 13 +++++++++++++
 include/linux/intel-iommu.h |  3 +++
 2 files changed, 16 insertions(+)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index e5a5209..ede0f2e 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -1484,6 +1484,19 @@ static void iommu_enable_dev_iotlb(struct device_domain_info *info)
 		return;
 
 	pdev = to_pci_dev(info->dev);
+	/* For IOMMU that supports device IOTLB throttling (DIT), we assign
+	 * PFSID to the invalidation desc of a VF such that IOMMU HW can gauge
+	 * queue depth at PF level. If DIT is not set, PFSID will be treated as
+	 * reserved, which should be set to 0.
+	 */
+	if (!ecap_dit(info->iommu->ecap))
+		info->pfsid = 0;
+	else if (pdev && pdev->is_virtfn) {
+		if (ecap_dit(info->iommu->ecap))
+			dev_warn(&pdev->dev, "SRIOV VF device IOTLB enabled without flow control\n");
+		info->pfsid = PCI_DEVID(pdev->physfn->bus->number, pdev->physfn->devfn);
+	} else
+		info->pfsid = PCI_DEVID(info->bus, info->devfn);
 
 #ifdef CONFIG_INTEL_IOMMU_SVM
 	/* The PCIe spec, in its wisdom, declares that the behaviour of
diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
index f42b46c..c8ac5c6 100644
--- a/include/linux/intel-iommu.h
+++ b/include/linux/intel-iommu.h
@@ -112,6 +112,7 @@
  * Extended Capability Register
  */
 
+#define ecap_dit(e)		((e >> 41) & 0x1)
 #define ecap_pasid(e)		((e >> 40) & 0x1)
 #define ecap_pss(e)		((e >> 35) & 0x1f)
 #define ecap_eafs(e)		((e >> 34) & 0x1)
@@ -285,6 +286,7 @@ enum {
 #define QI_DEV_IOTLB_SID(sid)	((u64)((sid) & 0xffff) << 32)
 #define QI_DEV_IOTLB_QDEP(qdep)	(((qdep) & 0x1f) << 16)
 #define QI_DEV_IOTLB_ADDR(addr)	((u64)(addr) & VTD_PAGE_MASK)
+#define QI_DEV_IOTLB_PFSID(pfsid) (((u64)(pfsid & 0xf) << 12) | ((u64)(pfsid & 0xff0) << 48))
 #define QI_DEV_IOTLB_SIZE	1
 #define QI_DEV_IOTLB_MAX_INVS	32
 
@@ -442,6 +444,7 @@ struct device_domain_info {
 	struct list_head global; /* link to global list */
 	u8 bus;			/* PCI bus number */
 	u8 devfn;		/* PCI devfn number */
+	u16 pfsid;		/* SRIOV physical function source ID */
 	u8 pasid_supported:3;
 	u8 pasid_enabled:1;
 	u8 pri_supported:1;
-- 
2.7.4