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[Qemu-devel] [PATCH] vfio: avoid adding same iommu mr for notify
From: |
Peter Xu |
Subject: |
[Qemu-devel] [PATCH] vfio: avoid adding same iommu mr for notify |
Date: |
Mon, 14 Nov 2016 19:59:28 -0500 |
When one IOMMU memory region is splitted into multiple memory sections,
vfio will register multiple same notifiers to a vIOMMU for the same
region. That's not sensible. What we need is to register one IOMMU
notifier for each IOMMU region, not per section.
Solution is simple - we traverse the container->giommu_list, and skip
the registration if memory region is already registered.
To make vfio's region_add() short, vfio_listener_region_add_iommu() is
introduced.
Signed-off-by: Peter Xu <address@hidden>
---
hw/vfio/common.c | 56 +++++++++++++++++++++++++++++++++++---------------------
1 file changed, 35 insertions(+), 21 deletions(-)
diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 801578b..5279fd1 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -360,6 +360,40 @@ out:
rcu_read_unlock();
}
+static void vfio_listener_region_add_iommu(VFIOContainer *container,
+ MemoryRegionSection *section,
+ hwaddr iova,
+ hwaddr end)
+{
+ VFIOGuestIOMMU *giommu;
+
+ QLIST_FOREACH(giommu, &container->giommu_list, giommu_next) {
+ if (giommu->iommu == section->mr) {
+ /* We have already registered with this MR, skip */
+ return;
+ }
+ }
+
+ trace_vfio_listener_region_add_iommu(iova, end);
+
+ /*
+ * FIXME: For VFIO iommu types which have KVM acceleration to
+ * avoid bouncing all map/unmaps through qemu this way, this
+ * would be the right place to wire that up (tell the KVM
+ * device emulation the VFIO iommu handles to use).
+ */
+ giommu = g_malloc0(sizeof(*giommu));
+ giommu->iommu = section->mr;
+ giommu->iommu_offset = section->offset_within_address_space -
+ section->offset_within_region;
+ giommu->container = container;
+ giommu->n.notify = vfio_iommu_map_notify;
+ giommu->n.notifier_flags = IOMMU_NOTIFIER_ALL;
+ QLIST_INSERT_HEAD(&container->giommu_list, giommu, giommu_next);
+ memory_region_register_iommu_notifier(giommu->iommu, &giommu->n);
+ memory_region_iommu_replay(giommu->iommu, &giommu->n, false);
+}
+
static void vfio_listener_region_add(MemoryListener *listener,
MemoryRegionSection *section)
{
@@ -439,27 +473,7 @@ static void vfio_listener_region_add(MemoryListener
*listener,
memory_region_ref(section->mr);
if (memory_region_is_iommu(section->mr)) {
- VFIOGuestIOMMU *giommu;
-
- trace_vfio_listener_region_add_iommu(iova, end);
- /*
- * FIXME: For VFIO iommu types which have KVM acceleration to
- * avoid bouncing all map/unmaps through qemu this way, this
- * would be the right place to wire that up (tell the KVM
- * device emulation the VFIO iommu handles to use).
- */
- giommu = g_malloc0(sizeof(*giommu));
- giommu->iommu = section->mr;
- giommu->iommu_offset = section->offset_within_address_space -
- section->offset_within_region;
- giommu->container = container;
- giommu->n.notify = vfio_iommu_map_notify;
- giommu->n.notifier_flags = IOMMU_NOTIFIER_ALL;
- QLIST_INSERT_HEAD(&container->giommu_list, giommu, giommu_next);
-
- memory_region_register_iommu_notifier(giommu->iommu, &giommu->n);
- memory_region_iommu_replay(giommu->iommu, &giommu->n, false);
-
+ vfio_listener_region_add_iommu(container, section, iova, end);
return;
}
--
2.7.4
- [Qemu-devel] [PATCH] vfio: avoid adding same iommu mr for notify,
Peter Xu <=