Re: [Qemu-devel] [PATCH RFC v3 07/14] memory: add section range info for IOMMU notifier

[Peter Xu]

On Fri, Jan 13, 2017 at 03:55:22PM +0800, Jason Wang wrote:
> 
> 
> On 2017年01月13日 11:06, Peter Xu wrote:
> >In this patch, IOMMUNotifier.{start|end} are introduced to store section
> >information for a specific notifier. When notification occurs, we not
> >only check the notification type (MAP|UNMAP), but also check whether the
> >notified iova is in the range of specific IOMMU notifier, and skip those
> >notifiers if not in the listened range.
> >
> >When removing an region, we need to make sure we removed the correct
> >VFIOGuestIOMMU by checking the IOMMUNotifier.start address as well.
> >
> >Suggested-by: David Gibson <address@hidden>
> >Reviewed-by: David Gibson <address@hidden>
> >Acked-by: Paolo Bonzini <address@hidden>
> >Signed-off-by: Peter Xu <address@hidden>
> >---
> >  hw/vfio/common.c      | 7 ++++++-
> >  include/exec/memory.h | 3 +++
> >  memory.c              | 4 +++-
> >  3 files changed, 12 insertions(+), 2 deletions(-)
> >
> >diff --git a/hw/vfio/common.c b/hw/vfio/common.c
> >index 801578b..6f648da 100644
> >--- a/hw/vfio/common.c
> >+++ b/hw/vfio/common.c
> >@@ -455,6 +455,10 @@ static void vfio_listener_region_add(MemoryListener 
> >*listener,
> >          giommu->container = container;
> >          giommu->n.notify = vfio_iommu_map_notify;
> >          giommu->n.notifier_flags = IOMMU_NOTIFIER_ALL;
> >+        giommu->n.start = section->offset_within_region;
> >+        llend = int128_add(int128_make64(giommu->n.start), section->size);
> >+        llend = int128_sub(llend, int128_one());
> >+        giommu->n.end = int128_get64(llend);
> >          QLIST_INSERT_HEAD(&container->giommu_list, giommu, giommu_next);
> >          memory_region_register_iommu_notifier(giommu->iommu, &giommu->n);
> >@@ -525,7 +529,8 @@ static void vfio_listener_region_del(MemoryListener 
> >*listener,
> >          VFIOGuestIOMMU *giommu;
> >          QLIST_FOREACH(giommu, &container->giommu_list, giommu_next) {
> >-            if (giommu->iommu == section->mr) {
> >+            if (giommu->iommu == section->mr &&
> >+                giommu->n.start == section->offset_within_region) {
> >                  memory_region_unregister_iommu_notifier(giommu->iommu,
> >                                                          &giommu->n);
> >                  QLIST_REMOVE(giommu, giommu_next);
> >diff --git a/include/exec/memory.h b/include/exec/memory.h
> >index bec9756..7649e74 100644
> >--- a/include/exec/memory.h
> >+++ b/include/exec/memory.h
> >@@ -84,6 +84,9 @@ typedef enum {
> >  struct IOMMUNotifier {
> >      void (*notify)(struct IOMMUNotifier *notifier, IOMMUTLBEntry *data);
> >      IOMMUNotifierFlag notifier_flags;
> >+    /* Notify for address space range start <= addr <= end */
> >+    hwaddr start;
> >+    hwaddr end;
> >      QLIST_ENTRY(IOMMUNotifier) node;
> >  };
> >  typedef struct IOMMUNotifier IOMMUNotifier;
> >diff --git a/memory.c b/memory.c
> >index 2bfc37f..e88bb54 100644
> >--- a/memory.c
> >+++ b/memory.c
> >@@ -1671,7 +1671,9 @@ void memory_region_notify_iommu(MemoryRegion *mr,
> >      }
> >      QLIST_FOREACH(iommu_notifier, &mr->iommu_notify, node) {
> >-        if (iommu_notifier->notifier_flags & request_flags) {
> >+        if (iommu_notifier->notifier_flags & request_flags &&
> >+            iommu_notifier->start <= entry.iova &&
> >+            iommu_notifier->end >= entry.iova) {
> >              iommu_notifier->notify(iommu_notifier, &entry);
> >          }
> >      }
> 
> This seems breaks vhost device IOTLB. How about keep the the behavior
> somehow?

Thanks to point out. How about I squash this into this patch?

--------8<--------
diff --git a/memory.c b/memory.c
index e88bb54..6de02dd 100644
--- a/memory.c
+++ b/memory.c
@@ -1608,8 +1608,14 @@ void memory_region_register_iommu_notifier(MemoryRegion 
*mr,
         return;
     }
 
+    if (n->start == 0 && n->end == 0) {
+        /* If these are not specified, we listen to the whole range */
+        n->end = (hwaddr)(-1);
+    }
+
     /* We need to register for at least one bitfield */
     assert(n->notifier_flags != IOMMU_NOTIFIER_NONE);
+    assert(n->start <= n->end);
     QLIST_INSERT_HEAD(&mr->iommu_notify, n, node);
     memory_region_update_iommu_notify_flags(mr);
 }
-------->8--------

-- peterx