Re: [Xen-devel] [PATCH v2 COLOPre 07/13] tools/libxl: Update libxl__domain_unpause() to support qemu-xen

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Mon, Jun 15, 2015 at 09:29:55AM +0800, Yang Hongyang wrote:
> 
> 
> On 06/12/2015 08:33 PM, Wei Liu wrote:
> >On Mon, Jun 08, 2015 at 11:43:11AM +0800, Yang Hongyang wrote:
> >>Currently, libxl__domain_unpause() only supports
> >>qemu-xen-traditional. Update it to support qemu-xen.
> >>
> >>Signed-off-by: Wen Congyang <wency@xxxxxxxxxxxxxx>
> >>Signed-off-by: Yang Hongyang <yanghy@xxxxxxxxxxxxxx>
> >
> >This looks very similar to an existing function called
> >libxl__domain_resume_device_model. Maybe you don't need to invent a new
> >function.
> >
> >>---
> >>  tools/libxl/libxl.c | 42 +++++++++++++++++++++++++++++++++---------
> >>  1 file changed, 33 insertions(+), 9 deletions(-)
> >>
> >>diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
> >>index d5691dc..5c843c2 100644
> >>--- a/tools/libxl/libxl.c
> >>+++ b/tools/libxl/libxl.c
> >>@@ -933,10 +933,37 @@ out:
> >>      return AO_INPROGRESS;
> >>  }
> >>
> >>-int libxl__domain_unpause(libxl__gc *gc, uint32_t domid)
> >>+static int libxl__domain_unpause_device_model(libxl__gc *gc, uint32_t 
> >>domid)
> >>  {
> >>      char *path;
> >>      char *state;
> >>+
> >>+    switch (libxl__device_model_version_running(gc, domid)) {
> >>+    case LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN_TRADITIONAL: {
> >>+        uint32_t dm_domid = libxl_get_stubdom_id(CTX, domid);
> >>+
> >>+        path = libxl__device_model_xs_path(gc, dm_domid, domid, "/state");
> >>+        state = libxl__xs_read(gc, XBT_NULL, path);
> >>+        if (state != NULL && !strcmp(state, "paused")) {
> >
> >The only difference between your function and
> >libxl__domain_unpause_device_model is the check for "state" node. I
> >think you can just add the check to libxl__domain_resume_device_model
> >and use that function.
> 
> I'm not sure if we change the existing function's behavior will affect the
> existing callers, if there's no problem to do so, I will do as what you
> said in the next version.
> 

Qemu-dm currently has several states. libxl__domain_resume_device_model
doesn't check the state and writes unconditionally. I think checking
before writing would be an improvement.

Wei.

> >
> >Wei.
> >.
> >
> 
> -- 
> Thanks,
> Yang.

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