> -----Original Message-----
> From: Stefano Stabellini [mailto:stefano.stabell...@eu.citrix.com]
> Sent: 10 October 2014 15:40
> To: Paul Durrant
> Cc: qemu-devel@nongnu.org; xen-de...@lists.xenproject.org; Michael S.
> Tsirkin; Stefano Stabellini; Peter Maydell; Paolo Bonzini; Michael Tokarev;
> Stefan Hajnoczi; Stefan Weil; Andreas Faerber"; Thomas Huth; Peter
> Crosthwaite; Eduardo Habkost; Gerd Hoffmann; Alexey Kardashevskiy;
> Alexander Graf
> Subject: Re: [PATCH] Xen: Use the ioreq-server API when available
>
> On Fri, 10 Oct 2014, Paul Durrant wrote:
> > The ioreq-server API added to Xen 4.5 offers better security than
> > the existing Xen/QEMU interface because the shared pages that are
> > used to pass emulation request/results back and forth are removed
> > from the guest's memory space before any requests are serviced.
> > This prevents the guest from mapping these pages (they are in a
> > well known location) and attempting to attack QEMU by synthesizing
> > its own request structures. Hence, this patch modifies configure
> > to detect whether the API is available, and adds the necessary
> > code to use the API if it is.
> >
> > The ioreq-server API does require that PCI device models explicitly
> > register with Xen for config space accesses, so to use the API the
> > code in xen-hvm.c needs to be informed as PCI devices are added or
> > removed from PCI buses. This patch therefore also adds a PCI bus
> > listener interface akin to the memory listener interface to fulfil
> > this need.
> >
> > Signed-off-by: Paul Durrant <paul.durr...@citrix.com>
> > Cc: Michael S. Tsirkin <m...@redhat.com>
> > Cc: Stefano Stabellini <stefano.stabell...@eu.citrix.com>
> > Cc: Peter Maydell <peter.mayd...@linaro.org>
> > Cc: Paolo Bonzini <pbonz...@redhat.com>
> > Cc: Michael Tokarev <m...@tls.msk.ru>
> > Cc: Stefan Hajnoczi <stefa...@redhat.com>
> > Cc: Stefan Weil <s...@weilnetz.de>
> > Cc: Andreas Faerber" <afaer...@suse.de>
> > Cc: Thomas Huth <th...@linux.vnet.ibm.com>
> > Cc: Peter Crosthwaite <peter.crosthwa...@xilinx.com>
> > Cc: Eduardo Habkost <ehabk...@redhat.com>
> > Cc: Gerd Hoffmann <kra...@redhat.com>
> > Cc: Alexey Kardashevskiy <a...@ozlabs.ru>
> > Cc: Alexander Graf <ag...@suse.de>
> > ---
> > configure | 29 ++++++
> > hw/pci/pci.c | 65 ++++++++++++
> > include/hw/pci/pci.h | 9 ++
> > include/qemu/typedefs.h | 1 +
> > trace-events | 8 ++
> > xen-hvm.c | 251
> +++++++++++++++++++++++++++++++++++++++++++----
> > 6 files changed, 345 insertions(+), 18 deletions(-)
>
> Please split this patch into two: one to introduce the PCI listener
> stuff and another for the Xen specific changes.
>
Originally it was, but I was uneasy about introducing an interface with no
consumers. Is that generally acceptable?
[snip]
> > diff --git a/xen-hvm.c b/xen-hvm.c
> > index 05e522c..031edd9 100644
> > --- a/xen-hvm.c
> > +++ b/xen-hvm.c
> > @@ -78,6 +78,7 @@ typedef struct XenPhysmap {
> > } XenPhysmap;
> >
> > typedef struct XenIOState {
> > + ioservid_t ioservid;
> > shared_iopage_t *shared_page;
> > buffered_iopage_t *buffered_io_page;
> > QEMUTimer *buffered_io_timer;
> > @@ -92,6 +93,8 @@ typedef struct XenIOState {
> >
> > struct xs_handle *xenstore;
> > MemoryListener memory_listener;
> > + MemoryListener io_listener;
> > + PCIListener pci_listener;
> > QLIST_HEAD(, XenPhysmap) physmap;
> > hwaddr free_phys_offset;
> > const XenPhysmap *log_for_dirtybit;
> > @@ -480,6 +483,20 @@ static void xen_region_add(MemoryListener
> *listener,
> > MemoryRegionSection *section)
> > {
> > memory_region_ref(section->mr);
> > +
> > +#if CONFIG_XEN_CTRL_INTERFACE_VERSION >= 450
>
> Please use include/hw/xen/xen_common.h for compat stuff. In this case
> you could provide an empty implementation of
> xc_hvm_map_io_range_to_ioreq_server. Try to remove ifdefs from
> xen-hvm.c.
>
Ok, I can do it that way; I was only following suit with the already #ifdefed
code in xen-hvm.c.
Paul
