| Message ID | 1462811480-16295-1-git-send-email-paul.durrant@citrix.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, May 09, 2016 at 05:31:20PM +0100, 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 <paul.durrant@citrix.com> > Cc: Stefano Stabellini <sstabellini@kernel.org> > Cc: Anthony Perard <anthony.perard@citrix.com> > Cc: Paolo Bonzini <pbonzini@redhat.com> Acked-by: Anthony PERARD <anthony.perard@citrix.com>
----- Original Message ----- > From: "Anthony PERARD" <anthony.perard@citrix.com> > To: "Paul Durrant" <paul.durrant@citrix.com> > Cc: qemu-devel@nongnu.org, xen-devel@lists.xenproject.org, "Stefano Stabellini" <sstabellini@kernel.org>, "Paolo > Bonzini" <pbonzini@redhat.com> > Sent: Wednesday, May 25, 2016 5:52:32 PM > Subject: Re: [PATCH v3] xen-hvm: ignore background I/O sections > > On Mon, May 09, 2016 at 05:31:20PM +0100, 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 <paul.durrant@citrix.com> > > Cc: Stefano Stabellini <sstabellini@kernel.org> > > Cc: Anthony Perard <anthony.perard@citrix.com> > > Cc: Paolo Bonzini <pbonzini@redhat.com> > > Acked-by: Anthony PERARD <anthony.perard@citrix.com> Do you have a signed GPG key or do I need to apply this for you? Thanks, Paolo
On Wed, 25 May 2016, Paolo Bonzini wrote: > > From: "Anthony PERARD" <anthony.perard@citrix.com> > > To: "Paul Durrant" <paul.durrant@citrix.com> > > Cc: qemu-devel@nongnu.org, xen-devel@lists.xenproject.org, "Stefano Stabellini" <sstabellini@kernel.org>, "Paolo > > Bonzini" <pbonzini@redhat.com> > > Sent: Wednesday, May 25, 2016 5:52:32 PM > > Subject: Re: [PATCH v3] xen-hvm: ignore background I/O sections > > > > On Mon, May 09, 2016 at 05:31:20PM +0100, 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 <paul.durrant@citrix.com> > > > Cc: Stefano Stabellini <sstabellini@kernel.org> > > > Cc: Anthony Perard <anthony.perard@citrix.com> > > > Cc: Paolo Bonzini <pbonzini@redhat.com> > > > > Acked-by: Anthony PERARD <anthony.perard@citrix.com> > > Do you have a signed GPG key or do I need to apply this for you? I was going to say, I'll just queue this up in my tree, but I don't have any other commits at this time, so if you are OK with applying this, I am fine with it too.
diff --git a/xen-hvm.c b/xen-hvm.c index 039680a..e394407 100644 --- a/xen-hvm.c +++ b/xen-hvm.c @@ -510,8 +510,13 @@ 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 +525,15 @@ 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,
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 <paul.durrant@citrix.com> Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Anthony Perard <anthony.perard@citrix.com> Cc: Paolo Bonzini <pbonzini@redhat.com> --- v3: - Really add missing braces. v2: - Add missing braces --- xen-hvm.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-)