[Qemu-devel] [PATCH 2/3] memory: add iommu_notify_flag

[Peter Xu]

When there are active IOMMU notify registers, the iommu_notify_flag will
cache existing notify flag. When notifiers are triggered, flag will be
checked against the cached result.

Signed-off-by: Peter Xu <pet...@redhat.com>
---
 hw/ppc/spapr_iommu.c     | 2 +-
 hw/s390x/s390-pci-inst.c | 2 +-
 include/exec/memory.h    | 6 +++++-
 memory.c                 | 6 +++++-
 4 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/hw/ppc/spapr_iommu.c b/hw/ppc/spapr_iommu.c
index 09660fc..14b1f00 100644
--- a/hw/ppc/spapr_iommu.c
+++ b/hw/ppc/spapr_iommu.c
@@ -411,7 +411,7 @@ static target_ulong put_tce_emu(sPAPRTCETable *tcet, 
target_ulong ioba,
     entry.translated_addr = tce & page_mask;
     entry.addr_mask = ~page_mask;
     entry.perm = spapr_tce_iommu_access_flags(tce);
-    memory_region_notify_iommu(&tcet->iommu, entry);
+    memory_region_notify_iommu(&tcet->iommu, entry, IOMMU_RW);
 
     return H_SUCCESS;
 }
diff --git a/hw/s390x/s390-pci-inst.c b/hw/s390x/s390-pci-inst.c
index f069b11..29ef345 100644
--- a/hw/s390x/s390-pci-inst.c
+++ b/hw/s390x/s390-pci-inst.c
@@ -616,7 +616,7 @@ int rpcit_service_call(S390CPU *cpu, uint8_t r1, uint8_t r2)
             goto out;
         }
 
-        memory_region_notify_iommu(mr, entry);
+        memory_region_notify_iommu(mr, entry, IOMMU_RW);
         start += entry.addr_mask + 1;
     }
 
diff --git a/include/exec/memory.h b/include/exec/memory.h
index 6c16a86..c67b3da 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -57,6 +57,7 @@ typedef enum {
     IOMMU_RO   = 1,
     IOMMU_WO   = 2,
     IOMMU_RW   = 3,
+    IOMMU_ACCESS_INVALID = 4,
 } IOMMUAccessFlags;
 
 struct IOMMUTLBEntry {
@@ -202,6 +203,7 @@ struct MemoryRegion {
     unsigned ioeventfd_nb;
     MemoryRegionIoeventfd *ioeventfds;
     NotifierList iommu_notify;
+    IOMMUAccessFlags iommu_notify_flag;
 };
 
 /**
@@ -611,9 +613,11 @@ uint64_t 
memory_region_iommu_get_min_page_size(MemoryRegion *mr);
  * @entry: the new entry in the IOMMU translation table.  The entry
  *         replaces all old entries for the same virtual I/O address range.
  *         Deleted entries have .@perm == 0.
+ * @flag: type of IOMMU notification (IOMMU_RW, IOMMU_NONE)
  */
 void memory_region_notify_iommu(MemoryRegion *mr,
-                                IOMMUTLBEntry entry);
+                                IOMMUTLBEntry entry,
+                                IOMMUAccessFlags flag);
 
 /**
  * memory_region_register_iommu_notifier: register a notifier for changes to
diff --git a/memory.c b/memory.c
index 747a9ec..5b50d15 100644
--- a/memory.c
+++ b/memory.c
@@ -1418,6 +1418,7 @@ void memory_region_init_iommu(MemoryRegion *mr,
     memory_region_init(mr, owner, name, size);
     mr->iommu_ops = ops,
     mr->terminates = true;  /* then re-forwards */
+    mr->iommu_notify_flag = IOMMU_ACCESS_INVALID;
     notifier_list_init(&mr->iommu_notify);
 }
 
@@ -1520,6 +1521,7 @@ void memory_region_register_iommu_notifier(MemoryRegion 
*mr, Notifier *n,
     if (mr->iommu_ops->notify_started &&
         QLIST_EMPTY(&mr->iommu_notify.notifiers)) {
         mr->iommu_ops->notify_started(mr, flag);
+        mr->iommu_notify_flag = flag;
     }
     notifier_list_add(&mr->iommu_notify, n);
 }
@@ -1560,13 +1562,15 @@ void 
memory_region_unregister_iommu_notifier(MemoryRegion *mr, Notifier *n)
     if (mr->iommu_ops->notify_stopped &&
         QLIST_EMPTY(&mr->iommu_notify.notifiers)) {
         mr->iommu_ops->notify_stopped(mr);
+        mr->iommu_notify_flag = IOMMU_ACCESS_INVALID;
     }
 }
 
 void memory_region_notify_iommu(MemoryRegion *mr,
-                                IOMMUTLBEntry entry)
+                                IOMMUTLBEntry entry, IOMMUAccessFlags flag)
 {
     assert(memory_region_is_iommu(mr));
+    assert(flag == mr->iommu_notify_flag);
     notifier_list_notify(&mr->iommu_notify, &entry);
 }
 
-- 
2.7.4