[PATCH ats_vtd v2 23/25] pci: add a pci-level API for ATS

[CLEMENT MATHIEU--DRIF <clement.mathieu--drif@eviden.com>]

Devices implementing ATS can send translation requests using
pci_ats_request_translation_pasid.

The invalidation events are sent back to the device using the iommu
notifier managed with pci_register_iommu_tlb_event_notifier and
pci_unregister_iommu_tlb_event_notifier

Signed-off-by: Clément Mathieu--Drif <clement.mathieu--drif@eviden.com>
---
 hw/pci/pci.c         | 44 +++++++++++++++++++++++++++++++++++++
 include/hw/pci/pci.h | 52 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 96 insertions(+)

diff --git a/hw/pci/pci.c b/hw/pci/pci.c
index f90eb04fda..20b838657e 100644
--- a/hw/pci/pci.c
+++ b/hw/pci/pci.c
@@ -2831,6 +2831,50 @@ void pci_device_unset_iommu_device(PCIDevice *dev)
     }
 }
 
+ssize_t pci_ats_request_translation_pasid(PCIDevice *dev, uint32_t pasid,
+                                          bool priv_req, bool exec_req, hwaddr addr,
+                                          size_t length, bool no_write,
+                                          IOMMUTLBEntry *result,
+                                          size_t result_length,
+                                          uint32_t *err_count)
+{
+    assert(result_length);
+    IOMMUMemoryRegion *iommu_mr = pci_device_iommu_memory_region_pasid(dev,
+                                                                        pasid);
+    if (!iommu_mr || !pcie_ats_enabled(dev)) {
+        return -EPERM;
+    }
+    return memory_region_iommu_ats_request_translation(iommu_mr, priv_req,
+                                                       exec_req, addr, length,
+                                                       no_write, result,
+                                                       result_length,
+                                                       err_count);
+}
+
+int pci_register_iommu_tlb_event_notifier(PCIDevice *dev, uint32_t pasid,
+                                          IOMMUNotifier *n)
+{
+    IOMMUMemoryRegion *iommu_mr = pci_device_iommu_memory_region_pasid(dev,
+                                                                        pasid);
+    if (!iommu_mr) {
+        return -EPERM;
+    }
+    return memory_region_register_iommu_notifier(MEMORY_REGION(iommu_mr), n,
+                                                 &error_fatal);
+}
+
+int pci_unregister_iommu_tlb_event_notifier(PCIDevice *dev, uint32_t pasid,
+                                             IOMMUNotifier *n)
+{
+    IOMMUMemoryRegion *iommu_mr = pci_device_iommu_memory_region_pasid(dev,
+                                                                        pasid);
+    if (!iommu_mr) {
+        return -EPERM;
+    }
+    memory_region_unregister_iommu_notifier(MEMORY_REGION(iommu_mr), n);
+    return 0;
+}
+
 void pci_setup_iommu(PCIBus *bus, const PCIIOMMUOps *ops, void *opaque)
 {
     /*
diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
index 1587c18cd9..dc247d24bd 100644
--- a/include/hw/pci/pci.h
+++ b/include/hw/pci/pci.h
@@ -471,6 +471,58 @@ void pci_device_unset_iommu_device(PCIDevice *dev);
 bool pci_iommu_init_iotlb_notifier(PCIDevice *dev, uint32_t pasid,
                                    IOMMUNotifier *n, IOMMUNotify fn);
 
+/**
+ * pci_ats_request_translation_pasid: perform an ATS request
+ *
+ * Return the number of translations stored in @result in case of success,
+ * a negative error code otherwise.
+ * -ENOMEM is returned when the result buffer is not large enough to store
+ * all the translations
+ *
+ * @dev: the ATS-capable PCI device
+ * @pasid: the pasid of the address space in which the translation will be made
+ * @priv_req: privileged mode bit (PASID TLP)
+ * @exec_req: execute request bit (PASID TLP)
+ * @addr: start address of the memory range to be translated
+ * @length: length of the memory range in bytes
+ * @no_write: request a read-only access translation (if supported by the IOMMU)
+ * @result: buffer in which the TLB entries will be stored
+ * @result_length: result buffer length
+ * @err_count: number of untranslated subregions
+ */
+ssize_t pci_ats_request_translation_pasid(PCIDevice *dev, uint32_t pasid,
+                                          bool priv_req, bool exec_req, hwaddr addr,
+                                          size_t length, bool no_write,
+                                          IOMMUTLBEntry *result,
+                                          size_t result_length,
+                                          uint32_t *err_count);
+
+/**
+ * pci_register_iommu_tlb_event_notifier: register a notifier for changes to
+ * IOMMU translation entries in a specific address space.
+ *
+ * Returns 0 on success, or a negative errno otherwise.
+ *
+ * @dev: the device that wants to get notified
+ * @pasid: the pasid of the address space to track
+ * @n: the notifier to register
+ */
+int pci_register_iommu_tlb_event_notifier(PCIDevice *dev, uint32_t pasid,
+                                          IOMMUNotifier *n);
+
+/**
+ * pci_unregister_iommu_tlb_event_notifier: unregister a notifier that has been
+ * registerd with pci_register_iommu_tlb_event_notifier
+ *
+ * Returns 0 on success, or a negative errno otherwise.
+ *
+ * @dev: the device that wants to unsubscribe
+ * @pasid: the pasid of the address space to be untracked
+ * @n: the notifier to unregister
+ */
+int pci_unregister_iommu_tlb_event_notifier(PCIDevice *dev, uint32_t pasid,
+                                            IOMMUNotifier *n);
+
 /**
  * pci_setup_iommu: Initialize specific IOMMU handlers for a PCIBus
  *
-- 
2.44.0