A pasid might be bound to a page table from a VM guest via the iommu
ops.sva_bind_gpasid. In this case, when a DMA page fault is detected
on the physical IOMMU, we need to inject the page fault request into
the guest. After the guest completes handling the page fault, a page
response need to be sent back via the iommu ops.page_response().
This adds support to report a page request fault. Any external module
which is interested in handling this fault should regiester a notifier
with iommu_register_device_fault_handler().
Co-developed-by: Jacob Pan <jacob.jun....@linux.intel.com>
Signed-off-by: Jacob Pan <jacob.jun....@linux.intel.com>
Co-developed-by: Liu Yi L <yi.l....@intel.com>
Signed-off-by: Liu Yi L <yi.l....@intel.com>
Signed-off-by: Lu Baolu <baolu...@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.t...@intel.com>
---
drivers/iommu/intel/svm.c | 103 +++++++++++++++++++++++++++++++-------
1 file changed, 85 insertions(+), 18 deletions(-)
diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index c104a50a625c..140114ab1375 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -811,8 +811,63 @@ static void intel_svm_drain_prq(struct device *dev, int
pasid)
}
}
+static int prq_to_iommu_prot(struct page_req_dsc *req)
+{
+ int prot = 0;
+
+ if (req->rd_req)
+ prot |= IOMMU_FAULT_PERM_READ;
+ if (req->wr_req)
+ prot |= IOMMU_FAULT_PERM_WRITE;
+ if (req->exe_req)
+ prot |= IOMMU_FAULT_PERM_EXEC;
+ if (req->pm_req)
+ prot |= IOMMU_FAULT_PERM_PRIV;
+
+ return prot;
+}
+
+static int
+intel_svm_prq_report(struct device *dev, struct page_req_dsc *desc)
+{
+ struct iommu_fault_event event;
+
+ if (!dev || !dev_is_pci(dev))
+ return -ENODEV;
+
+ /* Fill in event data for device specific processing */
+ memset(&event, 0, sizeof(struct iommu_fault_event));
+ event.fault.type = IOMMU_FAULT_PAGE_REQ;
+ event.fault.prm.addr = desc->addr;
+ event.fault.prm.pasid = desc->pasid;
+ event.fault.prm.grpid = desc->prg_index;
+ event.fault.prm.perm = prq_to_iommu_prot(desc);
+
+ if (desc->lpig)
+ event.fault.prm.flags |= IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE;
+ if (desc->pasid_present) {
+ event.fault.prm.flags |= IOMMU_FAULT_PAGE_REQUEST_PASID_VALID;
+ event.fault.prm.flags |= IOMMU_FAULT_PAGE_RESPONSE_NEEDS_PASID;
+ }
+ if (desc->priv_data_present) {
+ /*
+ * Set last page in group bit if private data is present,
+ * page response is required as it does for LPIG.
+ * iommu_report_device_fault() doesn't understand this vendor
+ * specific requirement thus we set last_page as a workaround.
+ */
+ event.fault.prm.flags |= IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE;
+ event.fault.prm.flags |= IOMMU_FAULT_PAGE_REQUEST_PRIV_DATA;
+ memcpy(event.fault.prm.private_data, desc->priv_data,
+ sizeof(desc->priv_data));
+ }
+
+ return iommu_report_device_fault(dev, &event);
+}
+
static irqreturn_t prq_event_thread(int irq, void *d)
{
+ struct intel_svm_dev *sdev = NULL;
struct intel_iommu *iommu = d;
struct intel_svm *svm = NULL;
int head, tail, handled = 0;
@@ -824,7 +879,6 @@ static irqreturn_t prq_event_thread(int irq, void *d)
tail = dmar_readq(iommu->reg + DMAR_PQT_REG) & PRQ_RING_MASK;
head = dmar_readq(iommu->reg + DMAR_PQH_REG) & PRQ_RING_MASK;
while (head != tail) {
- struct intel_svm_dev *sdev;
struct vm_area_struct *vma;
struct page_req_dsc *req;
struct qi_desc resp;
@@ -860,6 +914,20 @@ static irqreturn_t prq_event_thread(int irq, void *d)
}
}
+ if (!sdev || sdev->sid != req->rid) {
+ struct intel_svm_dev *t;
+
+ sdev = NULL;
+ rcu_read_lock();
+ list_for_each_entry_rcu(t, &svm->devs, list) {
+ if (t->sid == req->rid) {
+ sdev = t;
+ break;
+ }
+ }
+ rcu_read_unlock();
+ }
+
result = QI_RESP_INVALID;
/* Since we're using init_mm.pgd directly, we should never take
* any faults on kernel addresses. */
@@ -870,6 +938,17 @@ static irqreturn_t prq_event_thread(int irq, void *d)
if (!is_canonical_address(address))
goto bad_req;
+ /*
+ * If prq is to be handled outside iommu driver via receiver of
+ * the fault notifiers, we skip the page response here.
+ */
+ if (svm->flags & SVM_FLAG_GUEST_MODE) {
+ if (sdev && !intel_svm_prq_report(sdev->dev, req))
+ goto prq_advance;
+ else
+ goto bad_req;
+ }
+
/* If the mm is already defunct, don't handle faults. */
if (!mmget_not_zero(svm->mm))
goto bad_req;
@@ -888,24 +967,11 @@ static irqreturn_t prq_event_thread(int irq, void *d)
goto invalid;
result = QI_RESP_SUCCESS;
- invalid:
+invalid:
mmap_read_unlock(svm->mm);
mmput(svm->mm);
- bad_req:
- /* Accounting for major/minor faults? */
- rcu_read_lock();
- list_for_each_entry_rcu(sdev, &svm->devs, list) {
- if (sdev->sid == req->rid)
- break;
- }
- /* Other devices can go away, but the drivers are not permitted
- * to unbind while any page faults might be in flight. So it's
- * OK to drop the 'lock' here now we have it. */
- rcu_read_unlock();
-
- if (WARN_ON(&sdev->list == &svm->devs))
- sdev = NULL;
-
+bad_req:
+ WARN_ON(!sdev);
if (sdev && sdev->ops && sdev->ops->fault_cb) {
int rwxp = (req->rd_req << 3) | (req->wr_req << 2) |
(req->exe_req << 1) | (req->pm_req);
@@ -916,7 +982,7 @@ static irqreturn_t prq_event_thread(int irq, void *d)
and these can be NULL. Do not use them below this point! */
sdev = NULL;
svm = NULL;
- no_pasid:
+no_pasid:
if (req->lpig || req->priv_data_present) {
/*
* Per VT-d spec. v3.0 ch7.7, system software must
@@ -941,6 +1007,7 @@ static irqreturn_t prq_event_thread(int irq, void *d)
resp.qw3 = 0;
qi_submit_sync(iommu, &resp, 1, 0);
}
+prq_advance:
head = (head + sizeof(*req)) & PRQ_RING_MASK;
}
--
2.17.1
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