[PATCH v2 2/2] iommu/vt-d: Refactor PCI PRI enabling/disabling callbacks

Lu Baolu
2024-06-27T02:34:09Z

Commit 0095bf83554f8 ("iommu: Improve iopf_queue_remove_device()")
specified the flow for disabling the PRI on a device. Refactor the
PRI callbacks in the intel iommu driver to better manage PRI
enabling and disabling and align it with the device queue interfaces
in the iommu core.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
drivers/iommu/intel/iommu.h | 9 ++++++
drivers/iommu/intel/iommu.c | 57 +++++++++++++++++++++++++++++++++----
drivers/iommu/intel/pasid.c | 2 --
3 files changed, 61 insertions(+), 7 deletions(-)

diff --git a/drivers/iommu/intel/iommu.h b/drivers/iommu/intel/iommu.h
index 63eb3306c025..b67c14da1240 100644
--- a/drivers/iommu/intel/iommu.h
+++ b/drivers/iommu/intel/iommu.h
@@ -1045,6 +1045,15 @@ static inline void context_set_sm_pre(struct context_entry *context)
context->lo |= BIT_ULL(4);
}

+/*
+ * Clear the PRE(Page Request Enable) field of a scalable mode context
+ * entry.
+ */
+static inline void context_clear_sm_pre(struct context_entry *context)
+{
+ context->lo &= ~BIT_ULL(4);
+}
+
/* Returns a number of VTD pages, but aligned to MM page size */
static inline unsigned long aligned_nrpages(unsigned long host_addr, size_t size)
{
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 89f489372138..d51f840715e5 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -4241,6 +4241,37 @@ static int intel_iommu_enable_sva(struct device *dev)
return 0;
}

+static int context_flip_pri(struct device_domain_info *info, bool enable)
+{
+ struct intel_iommu *iommu = info->iommu;
+ u8 bus = info->bus, devfn = info->devfn;
+ struct context_entry *context;
+
+ spin_lock(&iommu->lock);
+ if (context_copied(iommu, bus, devfn)) {
+ spin_unlock(&iommu->lock);
+ return -EINVAL;
+ }
+
+ context = iommu_context_addr(iommu, bus, devfn, false);
+ if (!context || !context_present(context)) {
+ spin_unlock(&iommu->lock);
+ return -ENODEV;
+ }
+
+ if (enable)
+ context_set_sm_pre(context);
+ else
+ context_clear_sm_pre(context);
+
+ if (!ecap_coherent(iommu->ecap))
+ clflush_cache_range(context, sizeof(*context));
+ intel_context_flush_present(info, context, true);
+ spin_unlock(&iommu->lock);
+
+ return 0;
+}
+
static int intel_iommu_enable_iopf(struct device *dev)
{
struct pci_dev *pdev = dev_is_pci(dev) ? to_pci_dev(dev) : NULL;
@@ -4270,15 +4301,23 @@ static int intel_iommu_enable_iopf(struct device *dev)
if (ret)
return ret;

+ ret = context_flip_pri(info, true);
+ if (ret)
+ goto err_remove_device;
+
ret = pci_enable_pri(pdev, PRQ_DEPTH);
- if (ret) {
- iopf_queue_remove_device(iommu->iopf_queue, dev);
- return ret;
- }
+ if (ret)
+ goto err_clear_pri;

info->pri_enabled = 1;

return 0;
+err_clear_pri:
+ context_flip_pri(info, false);
+err_remove_device:
+ iopf_queue_remove_device(iommu->iopf_queue, dev);
+
+ return ret;
}

static int intel_iommu_disable_iopf(struct device *dev)
@@ -4289,6 +4328,15 @@ static int intel_iommu_disable_iopf(struct device *dev)
if (!info->pri_enabled)
return -EINVAL;

+ /* Disable new PRI reception: */
+ context_flip_pri(info, false);
+
+ /*
+ * Remove device from fault queue and acknowledge all outstanding
+ * PRQs to the device:
+ */
+ iopf_queue_remove_device(iommu->iopf_queue, dev);
+
/*
* PCIe spec states that by clearing PRI enable bit, the Page
* Request Interface will not issue new page requests, but has
@@ -4299,7 +4347,6 @@ static int intel_iommu_disable_iopf(struct device *dev)
*/
pci_disable_pri(to_pci_dev(dev));
info->pri_enabled = 0;
- iopf_queue_remove_device(iommu->iopf_queue, dev);

return 0;
}
diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c
index aef4b4afb873..b1ec9660bc11 100644
--- a/drivers/iommu/intel/pasid.c
+++ b/drivers/iommu/intel/pasid.c
@@ -749,8 +749,6 @@ static int context_entry_set_pasid_table(struct context_entry *context,

if (info->ats_supported)
context_set_sm_dte(context);
- if (info->pri_supported)
- context_set_sm_pre(context);
if (info->pasid_supported)
context_set_pasid(context);

--
2.34.1