[PATCH v2 15/19] memory: Add an API for ATS support

[CLEMENT MATHIEU--DRIF]

From: Clement Mathieu--Drif <clement.mathieu--drif@eviden.com>

IOMMU have to implement iommu_ats_request_translation to support ATS.

Devices can use IOMMU_TLB_ENTRY_TRANSLATION_ERROR to check the tlb
entries returned by a translation request.

We decided not to use the existing translation operation for 2 reasons.
First, ATS is designed to translate ranges and not isolated addresses.
Second, we need ATS-specific parameters.

Signed-off-by: Clement Mathieu--Drif <clement.mathieu--drif@eviden.com>
---
 include/exec/memory.h | 26 ++++++++++++++++++++++++++
 system/memory.c       | 21 +++++++++++++++++++++
 2 files changed, 47 insertions(+)

diff --git a/include/exec/memory.h b/include/exec/memory.h
index 468b003bf1..042d4ea5be 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -148,6 +148,10 @@ struct IOMMUTLBEntry {
     uint32_t         pasid;
 };
 
+/* Check if an IOMMU TLB entry indicates a translation error */
+#define IOMMU_TLB_ENTRY_TRANSLATION_ERROR(entry) ((((entry)->perm) & IOMMU_RW) 
\
+                                                    == IOMMU_NONE)
+
 /*
  * Bitmap for different IOMMUNotifier capabilities. Each notifier can
  * register with one or multiple IOMMU Notifier capability bit(s).
@@ -525,6 +529,20 @@ struct IOMMUMemoryRegionClass {
      * @iommu: the IOMMUMemoryRegion
      */
     int (*num_indexes)(IOMMUMemoryRegion *iommu);
+
+    /**
+     * @iommu_ats_request_translation:
+     * This method must be implemented if the IOMMU has ATS enabled
+     *
+     * @see pci_ats_request_translation_pasid
+     */
+    ssize_t (*iommu_ats_request_translation)(IOMMUMemoryRegion *iommu,
+                                             bool priv_req, bool exec_req,
+                                             hwaddr addr, size_t length,
+                                             bool no_write,
+                                             IOMMUTLBEntry *result,
+                                             size_t result_length,
+                                             uint32_t *err_count);
 };
 
 typedef struct RamDiscardListener RamDiscardListener;
@@ -1882,6 +1900,14 @@ void memory_region_iommu_replay(IOMMUMemoryRegion 
*iommu_mr, IOMMUNotifier *n);
 void memory_region_unregister_iommu_notifier(MemoryRegion *mr,
                                              IOMMUNotifier *n);
 
+ssize_t memory_region_iommu_ats_request_translation(IOMMUMemoryRegion 
*iommu_mr,
+                                                bool priv_req, bool exec_req,
+                                                hwaddr addr, size_t length,
+                                                bool no_write,
+                                                IOMMUTLBEntry *result,
+                                                size_t result_length,
+                                                uint32_t *err_count);
+
 /**
  * memory_region_iommu_get_attr: return an IOMMU attr if get_attr() is
  * defined on the IOMMU.
diff --git a/system/memory.c b/system/memory.c
index b17b5538ff..0a379a72bb 100644
--- a/system/memory.c
+++ b/system/memory.c
@@ -2011,6 +2011,27 @@ void 
memory_region_unregister_iommu_notifier(MemoryRegion *mr,
     memory_region_update_iommu_notify_flags(iommu_mr, NULL);
 }
 
+ssize_t memory_region_iommu_ats_request_translation(IOMMUMemoryRegion 
*iommu_mr,
+                                                    bool priv_req,
+                                                    bool exec_req,
+                                                    hwaddr addr, size_t length,
+                                                    bool no_write,
+                                                    IOMMUTLBEntry *result,
+                                                    size_t result_length,
+                                                    uint32_t *err_count)
+{
+    IOMMUMemoryRegionClass *imrc =
+        memory_region_get_iommu_class_nocheck(iommu_mr);
+
+    if (!imrc->iommu_ats_request_translation) {
+        return -ENODEV;
+    }
+
+    return imrc->iommu_ats_request_translation(iommu_mr, priv_req, exec_req,
+                                               addr, length, no_write, result,
+                                               result_length, err_count);
+}
+
 void memory_region_notify_iommu_one(IOMMUNotifier *notifier,
                                     const IOMMUTLBEvent *event)
 {
-- 
2.47.1