iommu/vt-d: Add basic SVM PASID support
This provides basic PASID support for endpoint devices, tested with a
version of the i915 driver.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index 5b42a95..82d53e1 100644
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -14,6 +14,17 @@
*/
#include <linux/intel-iommu.h>
+#include <linux/mmu_notifier.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/intel-svm.h>
+#include <linux/rculist.h>
+#include <linux/pci.h>
+#include <linux/pci-ats.h>
+
+struct pasid_entry {
+ u64 val;
+};
int intel_svm_alloc_pasid_tables(struct intel_iommu *iommu)
{
@@ -42,6 +53,8 @@
iommu->name);
}
+ idr_init(&iommu->pasid_idr);
+
return 0;
}
@@ -61,5 +74,283 @@
free_pages((unsigned long)iommu->pasid_state_table, order);
iommu->pasid_state_table = NULL;
}
+ idr_destroy(&iommu->pasid_idr);
return 0;
}
+
+static void intel_flush_svm_range_dev (struct intel_svm *svm, struct intel_svm_dev *sdev,
+ unsigned long address, int pages, int ih)
+{
+ struct qi_desc desc;
+ int mask = ilog2(__roundup_pow_of_two(pages));
+
+ if (pages == -1 || !cap_pgsel_inv(svm->iommu->cap) ||
+ mask > cap_max_amask_val(svm->iommu->cap)) {
+ desc.low = QI_EIOTLB_PASID(svm->pasid) | QI_EIOTLB_DID(sdev->did) |
+ QI_EIOTLB_GRAN(QI_GRAN_NONG_PASID) | QI_EIOTLB_TYPE;
+ desc.high = 0;
+ } else {
+ desc.low = QI_EIOTLB_PASID(svm->pasid) | QI_EIOTLB_DID(sdev->did) |
+ QI_EIOTLB_GRAN(QI_GRAN_PSI_PASID) | QI_EIOTLB_TYPE;
+ desc.high = QI_EIOTLB_ADDR(address) | QI_EIOTLB_GL(1) |
+ QI_EIOTLB_IH(ih) | QI_EIOTLB_AM(mask);
+ }
+
+ qi_submit_sync(&desc, svm->iommu);
+
+ if (sdev->dev_iotlb) {
+ desc.low = QI_DEV_EIOTLB_PASID(svm->pasid) | QI_DEV_EIOTLB_SID(sdev->sid) |
+ QI_DEV_EIOTLB_QDEP(sdev->qdep) | QI_DEIOTLB_TYPE;
+ if (mask) {
+ unsigned long adr, delta;
+
+ /* Least significant zero bits in the address indicate the
+ * range of the request. So mask them out according to the
+ * size. */
+ adr = address & ((1<<(VTD_PAGE_SHIFT + mask)) - 1);
+
+ /* Now ensure that we round down further if the original
+ * request was not aligned w.r.t. its size */
+ delta = address - adr;
+ if (delta + (pages << VTD_PAGE_SHIFT) >= (1 << (VTD_PAGE_SHIFT + mask)))
+ adr &= ~(1 << (VTD_PAGE_SHIFT + mask));
+ desc.high = QI_DEV_EIOTLB_ADDR(adr) | QI_DEV_EIOTLB_SIZE;
+ } else {
+ desc.high = QI_DEV_EIOTLB_ADDR(address);
+ }
+ qi_submit_sync(&desc, svm->iommu);
+ }
+}
+
+static void intel_flush_svm_range(struct intel_svm *svm, unsigned long address,
+ int pages, int ih)
+{
+ struct intel_svm_dev *sdev;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(sdev, &svm->devs, list)
+ intel_flush_svm_range_dev(svm, sdev, address, pages, ih);
+ rcu_read_unlock();
+}
+
+static void intel_change_pte(struct mmu_notifier *mn, struct mm_struct *mm,
+ unsigned long address, pte_t pte)
+{
+ struct intel_svm *svm = container_of(mn, struct intel_svm, notifier);
+
+ intel_flush_svm_range(svm, address, 1, 1);
+}
+
+static void intel_invalidate_page(struct mmu_notifier *mn, struct mm_struct *mm,
+ unsigned long address)
+{
+ struct intel_svm *svm = container_of(mn, struct intel_svm, notifier);
+
+ intel_flush_svm_range(svm, address, 1, 1);
+}
+
+/* Pages have been freed at this point */
+static void intel_invalidate_range(struct mmu_notifier *mn,
+ struct mm_struct *mm,
+ unsigned long start, unsigned long end)
+{
+ struct intel_svm *svm = container_of(mn, struct intel_svm, notifier);
+
+ intel_flush_svm_range(svm, start,
+ (end - start + PAGE_SIZE - 1) >> VTD_PAGE_SHIFT , 0);
+}
+
+
+static void intel_flush_pasid_dev(struct intel_svm *svm, struct intel_svm_dev *sdev)
+{
+ struct qi_desc desc;
+
+ desc.high = 0;
+ desc.low = QI_PC_TYPE | QI_PC_DID(sdev->did) | QI_PC_PASID_SEL | QI_PC_PASID(svm->pasid);
+
+ qi_submit_sync(&desc, svm->iommu);
+}
+
+static void intel_mm_release(struct mmu_notifier *mn, struct mm_struct *mm)
+{
+ struct intel_svm *svm = container_of(mn, struct intel_svm, notifier);
+
+ svm->iommu->pasid_table[svm->pasid].val = 0;
+
+ /* There's no need to do any flush because we can't get here if there
+ * are any devices left anyway. */
+ WARN_ON(!list_empty(&svm->devs));
+}
+
+static const struct mmu_notifier_ops intel_mmuops = {
+ .release = intel_mm_release,
+ .change_pte = intel_change_pte,
+ .invalidate_page = intel_invalidate_page,
+ .invalidate_range = intel_invalidate_range,
+};
+
+static DEFINE_MUTEX(pasid_mutex);
+
+int intel_svm_bind_mm(struct device *dev, int *pasid)
+{
+ struct intel_iommu *iommu = intel_svm_device_to_iommu(dev);
+ struct intel_svm_dev *sdev;
+ struct intel_svm *svm = NULL;
+ int pasid_max;
+ int ret;
+
+ BUG_ON(pasid && !current->mm);
+
+ if (WARN_ON(!iommu))
+ return -EINVAL;
+
+ if (dev_is_pci(dev)) {
+ pasid_max = pci_max_pasids(to_pci_dev(dev));
+ if (pasid_max < 0)
+ return -EINVAL;
+ } else
+ pasid_max = 1 << 20;
+
+ mutex_lock(&pasid_mutex);
+ if (pasid) {
+ int i;
+
+ idr_for_each_entry(&iommu->pasid_idr, svm, i) {
+ if (svm->mm != current->mm)
+ continue;
+
+ if (svm->pasid >= pasid_max) {
+ dev_warn(dev,
+ "Limited PASID width. Cannot use existing PASID %d\n",
+ svm->pasid);
+ ret = -ENOSPC;
+ goto out;
+ }
+
+ list_for_each_entry(sdev, &svm->devs, list) {
+ if (dev == sdev->dev) {
+ sdev->users++;
+ goto success;
+ }
+ }
+
+ break;
+ }
+ }
+
+ sdev = kzalloc(sizeof(*sdev), GFP_KERNEL);
+ if (!sdev) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ sdev->dev = dev;
+
+ ret = intel_iommu_enable_pasid(iommu, sdev);
+ if (ret || !pasid) {
+ /* If they don't actually want to assign a PASID, this is
+ * just an enabling check/preparation. */
+ kfree(sdev);
+ goto out;
+ }
+ /* Finish the setup now we know we're keeping it */
+ sdev->users = 1;
+ init_rcu_head(&sdev->rcu);
+
+ if (!svm) {
+ svm = kzalloc(sizeof(*svm), GFP_KERNEL);
+ if (!svm) {
+ ret = -ENOMEM;
+ kfree(sdev);
+ goto out;
+ }
+ svm->iommu = iommu;
+
+ if (pasid_max > 2 << ecap_pss(iommu->ecap))
+ pasid_max = 2 << ecap_pss(iommu->ecap);
+
+ ret = idr_alloc(&iommu->pasid_idr, svm, 0, pasid_max - 1,
+ GFP_KERNEL);
+ if (ret < 0) {
+ kfree(svm);
+ goto out;
+ }
+ svm->pasid = ret;
+ svm->notifier.ops = &intel_mmuops;
+ svm->mm = get_task_mm(current);
+ INIT_LIST_HEAD_RCU(&svm->devs);
+ ret = -ENOMEM;
+ if (!svm->mm || (ret = mmu_notifier_register(&svm->notifier, svm->mm))) {
+ idr_remove(&svm->iommu->pasid_idr, svm->pasid);
+ kfree(svm);
+ kfree(sdev);
+ goto out;
+ }
+ iommu->pasid_table[svm->pasid].val = (u64)__pa(svm->mm->pgd) | 1;
+ wmb();
+ }
+ list_add_rcu(&sdev->list, &svm->devs);
+
+ success:
+ *pasid = svm->pasid;
+ ret = 0;
+ out:
+ mutex_unlock(&pasid_mutex);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(intel_svm_bind_mm);
+
+int intel_svm_unbind_mm(struct device *dev, int pasid)
+{
+ struct intel_svm_dev *sdev;
+ struct intel_iommu *iommu;
+ struct intel_svm *svm;
+ int ret = -EINVAL;
+
+ mutex_lock(&pasid_mutex);
+ iommu = intel_svm_device_to_iommu(dev);
+ if (!iommu || !iommu->pasid_table)
+ goto out;
+
+ svm = idr_find(&iommu->pasid_idr, pasid);
+ if (!svm)
+ goto out;
+
+ list_for_each_entry(sdev, &svm->devs, list) {
+ if (dev == sdev->dev) {
+ ret = 0;
+ sdev->users--;
+ if (!sdev->users) {
+ list_del_rcu(&sdev->list);
+ /* Flush the PASID cache and IOTLB for this device.
+ * Note that we do depend on the hardware *not* using
+ * the PASID any more. Just as we depend on other
+ * devices never using PASIDs that they have no right
+ * to use. We have a *shared* PASID table, because it's
+ * large and has to be physically contiguous. So it's
+ * hard to be as defensive as we might like. */
+ intel_flush_pasid_dev(svm, sdev);
+ intel_flush_svm_range_dev(svm, sdev, 0, -1, 0);
+ kfree_rcu(sdev, rcu);
+
+ if (list_empty(&svm->devs)) {
+ mmu_notifier_unregister(&svm->notifier, svm->mm);
+
+ idr_remove(&svm->iommu->pasid_idr, svm->pasid);
+ mmput(svm->mm);
+ /* We mandate that no page faults may be outstanding
+ * for the PASID when intel_svm_unbind_mm() is called.
+ * If that is not obeyed, subtle errors will happen.
+ * Let's make them less subtle... */
+ memset(svm, 0x6b, sizeof(*svm));
+ kfree(svm);
+ }
+ }
+ break;
+ }
+ }
+ out:
+ mutex_unlock(&pasid_mutex);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(intel_svm_unbind_mm);