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[Qemu-devel] [PATCH v2] xen-hvm: ignore background I/O sections
From: |
Paul Durrant |
Subject: |
[Qemu-devel] [PATCH v2] xen-hvm: ignore background I/O sections |
Date: |
Mon, 9 May 2016 17:29:23 +0100 |
Since Xen will correctly handle accesses to unimplemented I/O ports (by
returning all 1's for reads and ignoring writes) there is no need for
QEMU to register backgroud I/O sections.
This patch therefore adds checks to xen_io_add/del so that sections with
memory-region ops pointing at 'unassigned_io_ops' are ignored.
Signed-off-by: Paul Durrant <address@hidden>
Cc: Stefano Stabellini <address@hidden>
Cc: Anthony Perard <address@hidden>
Cc: Paolo Bonzini <address@hidden>
---
v2:
- Add missing braces
---
xen-hvm.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/xen-hvm.c b/xen-hvm.c
index 039680a..8ab44f0 100644
--- a/xen-hvm.c
+++ b/xen-hvm.c
@@ -510,8 +510,12 @@ static void xen_io_add(MemoryListener *listener,
MemoryRegionSection *section)
{
XenIOState *state = container_of(listener, XenIOState, io_listener);
+ MemoryRegion *mr = section->mr;
- memory_region_ref(section->mr);
+ if (mr->ops == &unassigned_io_ops)
+ return;
+
+ memory_region_ref(mr);
xen_map_io_section(xen_xc, xen_domid, state->ioservid, section);
}
@@ -520,10 +524,14 @@ static void xen_io_del(MemoryListener *listener,
MemoryRegionSection *section)
{
XenIOState *state = container_of(listener, XenIOState, io_listener);
+ MemoryRegion *mr = section->mr;
+
+ if (mr->ops == &unassigned_io_ops)
+ return;
xen_unmap_io_section(xen_xc, xen_domid, state->ioservid, section);
- memory_region_unref(section->mr);
+ memory_region_unref(mr);
}
static void xen_device_realize(DeviceListener *listener,
--
2.1.4
- [Qemu-devel] [PATCH v2] xen-hvm: ignore background I/O sections,
Paul Durrant <=