From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47770) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1azoD8-0003v6-PY for qemu-devel@nongnu.org; Mon, 09 May 2016 12:39:11 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1azoD4-0005Nb-G4 for qemu-devel@nongnu.org; Mon, 09 May 2016 12:39:09 -0400 Received: from mx1.redhat.com ([209.132.183.28]:32845) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1azoD4-0005NQ-Ac for qemu-devel@nongnu.org; Mon, 09 May 2016 12:39:06 -0400 References: <1462810695-16072-1-git-send-email-paul.durrant@citrix.com> From: Paolo Bonzini Message-ID: <5730BD25.6060300@redhat.com> Date: Mon, 9 May 2016 18:39:01 +0200 MIME-Version: 1.0 In-Reply-To: <1462810695-16072-1-git-send-email-paul.durrant@citrix.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] xen-hvm: ignore background I/O sections List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paul Durrant , qemu-devel@nongnu.org, xen-devel@lists.xenproject.org Cc: Stefano Stabellini , Anthony Perard On 09/05/2016 18:18, Paul Durrant wrote: > 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; Missing braces, same in xen_io_del. Otherwise looks ok. Paolo > + 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, >