[PATCH 1/2] dmaengine: idxd: Add enable/disable device IOPF feature

Lu Baolu
2023-02-03T08:53:33Z

The iommu subsystem requires IOMMU_DEV_FEAT_IOPF must be enabled before
and disabled after IOMMU_DEV_FEAT_SVA, if device's I/O page faults rely
on the IOMMU. Add explicit IOMMU_DEV_FEAT_IOPF enabling/disabling in this
driver.

At present, missing IOPF enabling/disabling doesn't cause any real issue,
because the IOMMU driver places the IOPF enabling/disabling in the path
of SVA feature handling. But this may change.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
drivers/dma/idxd/init.c | 31 +++++++++++++++++++++++++------
1 file changed, 25 insertions(+), 6 deletions(-)

diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
index 529ea09c9094..d5a709a842a8 100644
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c
@@ -511,6 +511,27 @@ static void idxd_disable_system_pasid(struct idxd_device *idxd)
idxd->sva = NULL;
}

+static int idxd_enable_sva(struct pci_dev *pdev)
+{
+ int ret;
+
+ ret = iommu_dev_enable_feature(&pdev->dev, IOMMU_DEV_FEAT_IOPF);
+ if (ret)
+ return ret;
+
+ ret = iommu_dev_enable_feature(&pdev->dev, IOMMU_DEV_FEAT_SVA);
+ if (ret)
+ iommu_dev_disable_feature(&pdev->dev, IOMMU_DEV_FEAT_IOPF);
+
+ return ret;
+}
+
+static void idxd_disable_sva(struct pci_dev *pdev)
+{
+ iommu_dev_disable_feature(&pdev->dev, IOMMU_DEV_FEAT_SVA);
+ iommu_dev_disable_feature(&pdev->dev, IOMMU_DEV_FEAT_IOPF);
+}
+
static int idxd_probe(struct idxd_device *idxd)
{
struct pci_dev *pdev = idxd->pdev;
@@ -525,7 +546,7 @@ static int idxd_probe(struct idxd_device *idxd)
dev_dbg(dev, "IDXD reset complete\n");

if (IS_ENABLED(CONFIG_INTEL_IDXD_SVM) && sva) {
- if (iommu_dev_enable_feature(dev, IOMMU_DEV_FEAT_SVA)) {
+ if (idxd_enable_sva(pdev)) {
dev_warn(dev, "Unable to turn on user SVA feature.\n");
} else {
set_bit(IDXD_FLAG_USER_PASID_ENABLED, &idxd->flags);
@@ -573,21 +594,19 @@ static int idxd_probe(struct idxd_device *idxd)
if (device_pasid_enabled(idxd))
idxd_disable_system_pasid(idxd);
if (device_user_pasid_enabled(idxd))
- iommu_dev_disable_feature(dev, IOMMU_DEV_FEAT_SVA);
+ idxd_disable_sva(pdev);
return rc;
}

static void idxd_cleanup(struct idxd_device *idxd)
{
- struct device *dev = &idxd->pdev->dev;
-
perfmon_pmu_remove(idxd);
idxd_cleanup_interrupts(idxd);
idxd_cleanup_internals(idxd);
if (device_pasid_enabled(idxd))
idxd_disable_system_pasid(idxd);
if (device_user_pasid_enabled(idxd))
- iommu_dev_disable_feature(dev, IOMMU_DEV_FEAT_SVA);
+ idxd_disable_sva(idxd->pdev);
}

static int idxd_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
@@ -705,7 +724,7 @@ static void idxd_remove(struct pci_dev *pdev)
pci_free_irq_vectors(pdev);
pci_iounmap(pdev, idxd->reg_base);
if (device_user_pasid_enabled(idxd))
- iommu_dev_disable_feature(&pdev->dev, IOMMU_DEV_FEAT_SVA);
+ idxd_disable_sva(pdev);
pci_disable_device(pdev);
destroy_workqueue(idxd->wq);
perfmon_pmu_remove(idxd);
--
2.34.1