From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38882) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1azp2v-0000Dh-2K for qemu-devel@nongnu.org; Mon, 09 May 2016 13:32:42 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1azp2r-0000mj-PY for qemu-devel@nongnu.org; Mon, 09 May 2016 13:32:40 -0400 Received: from smtp02.citrix.com ([66.165.176.63]:15997) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1azp2r-0000mY-GI for qemu-devel@nongnu.org; Mon, 09 May 2016 13:32:37 -0400 From: Paul Durrant Date: Mon, 9 May 2016 17:18:15 +0100 Message-ID: <1462810695-16072-1-git-send-email-paul.durrant@citrix.com> MIME-Version: 1.0 Content-Type: text/plain Subject: [Qemu-devel] [PATCH] xen-hvm: ignore background I/O sections List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, xen-devel@lists.xenproject.org Cc: Paul Durrant , Stefano Stabellini , Anthony Perard , Paolo Bonzini 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 Cc: Stefano Stabellini Cc: Anthony Perard Cc: Paolo Bonzini --- 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