On Wed, 9 Dec 2015, Jianzhong,Chang wrote:
> Add pci = [ '$VF_BDF1', '$VF_BDF2', '$VF_BDF3'] in
> hvm guest configuration file. After the guest boot up,
> detach the VFs in sequence by
> "xl pci-detach $DOMID $VF_BDF1"
> "xl pci-detach $DOMID $VF_BDF2"
> "xl pci-detach $DOMID $VF_BDF3"
> and reattach the VFs in sequence by
> "xl pci-attach $DOMID $VF_BDF1"
> "xl pci-attach $DOMID $VF_BDF2"
> "xl pci-attach $DOMID $VF_BDF3"
> An error message will be reported like this:
> "libxl: error: libxl_qmp.c:287:qmp_handle_error_response: received
> an error message from QMP server: Duplicate ID 'pci-pt-07_10.1' for device"
>
> When xen_pt_region_add/del() is called, MemoryRegion
> may not belong to the XenPCIPassthroughState.
> xen_pt_region_update() checks it but memory_region_ref/unref() does not.
> This case causes obj->ref issue and affects the release of related objects.
> So, memory_region_ref/unref() is moved from
> xen_pt_region_add/del to xen_pt_region_update.
>
> Signed-off-by: Jianzhong,Chang <jianzhongx.ch...@intel.com>
This is much better, thanks! I have just one minor ask, see below.
> hw/xen/xen_pt.c | 13 ++++++++-----
> 1 files changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/hw/xen/xen_pt.c b/hw/xen/xen_pt.c
> index aa96288..b963208 100644
> --- a/hw/xen/xen_pt.c
> +++ b/hw/xen/xen_pt.c
> @@ -590,11 +590,15 @@ static void xen_pt_region_update(XenPCIPassthroughState
> *s,
> if (bar == -1 && (!s->msix || &s->msix->mmio != mr)) {
> return;
> }
> -
> + if (adding) {
> + memory_region_ref(mr);
> + }
> if (s->msix && &s->msix->mmio == mr) {
> if (adding) {
> s->msix->mmio_base_addr = sec->offset_within_address_space;
> rc = xen_pt_msix_update_remap(s, s->msix->bar_index);
> + } else {
> + memory_region_unref(mr);
> }
Instead of this, could you please add an out label below, where you call
memory_region_unref, and here just goto out;
> return;
> }
> @@ -635,6 +639,9 @@ static void xen_pt_region_update(XenPCIPassthroughState
> *s,
> adding ? "create new" : "remove old", errno);
> }
> }
> + if (!adding) {
> + memory_region_unref(mr);
> + }
> }
>
> static void xen_pt_region_add(MemoryListener *l, MemoryRegionSection *sec)
> @@ -642,7 +649,6 @@ static void xen_pt_region_add(MemoryListener *l,
> MemoryRegionSection *sec)
> XenPCIPassthroughState *s = container_of(l, XenPCIPassthroughState,
> memory_listener);
>
> - memory_region_ref(sec->mr);
> xen_pt_region_update(s, sec, true);
> }
>
> @@ -652,7 +658,6 @@ static void xen_pt_region_del(MemoryListener *l,
> MemoryRegionSection *sec)
> memory_listener);
>
> xen_pt_region_update(s, sec, false);
> - memory_region_unref(sec->mr);
> }
>
> static void xen_pt_io_region_add(MemoryListener *l, MemoryRegionSection *sec)
> @@ -660,7 +665,6 @@ static void xen_pt_io_region_add(MemoryListener *l,
> MemoryRegionSection *sec)
> XenPCIPassthroughState *s = container_of(l, XenPCIPassthroughState,
> io_listener);
>
> - memory_region_ref(sec->mr);
> xen_pt_region_update(s, sec, true);
> }
>
> @@ -670,7 +674,6 @@ static void xen_pt_io_region_del(MemoryListener *l,
> MemoryRegionSection *sec)
> io_listener);
>
> xen_pt_region_update(s, sec, false);
> - memory_region_unref(sec->mr);
> }
>
> static const MemoryListener xen_pt_memory_listener = {
> --
> 1.7.1
>
