Re: [PATCH v3 4/6] libxl: change xs path for QEMU

[Stefano Stabellini <stefano.stabellini@eu.citrix.com>]

On Thu, 25 Jun 2015, Ian Campbell wrote:
> On Wed, 2015-06-10 at 11:09 +0100, Stefano Stabellini wrote:
> > Change the QEMU xenstore watch path to
> > /local/domain/$LIBXL_TOOLSTACK_DOMID/device-model/$DOMID/$EMULATOR_ID.
> 
> This and the next patch should both be changing the xenstore-paths doc
> too.

OK

> 
> > Currently two emulator_ids are statically allocated: one for device models and
> > one for pv qemus.
> > 
> > Add a parameter to libxl__device_model_xs_path to distinguish the device
> > model from the pv backends provider.
> > 
> > Store the device model binary path under
> > /local/domain/$DOMID/device-model on xenstore, so that we can fetch it
> > later and retrieve the list of supported options from
> > /local/domain/$LIBXL_TOOLSTACK_DOMID/libxl/$device_model_binary,
> > introduce in the previous path.
> > 
> > Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> > 
> > ---
> > 
> > Changes in v3:
> > - use LIBXL_TOOLSTACK_DOMID instead of 0 in the commit message
> > - change xs path to include the emulator_id
> > ---
> >  tools/libxl/libxl.c          |    2 +-
> >  tools/libxl/libxl_create.c   |    3 +++
> >  tools/libxl/libxl_device.c   |    2 +-
> >  tools/libxl/libxl_dm.c       |   18 ++++++++++--------
> >  tools/libxl/libxl_dom.c      |   12 ++++++------
> >  tools/libxl/libxl_internal.c |   19 +++++++++++++++----
> >  tools/libxl/libxl_internal.h |    5 ++---
> >  tools/libxl/libxl_pci.c      |   14 +++++++-------
> >  8 files changed, 45 insertions(+), 30 deletions(-)
> > 
> > diff --git a/tools/libxl/libxl.c b/tools/libxl/libxl.c
> > index 516713e..bca4c88 100644
> > --- a/tools/libxl/libxl.c
> > +++ b/tools/libxl/libxl.c
> > @@ -1035,7 +1035,7 @@ int libxl_domain_unpause(libxl_ctx *ctx, uint32_t domid)
> >      if (type == LIBXL_DOMAIN_TYPE_HVM) {
> >          uint32_t dm_domid = libxl_get_stubdom_id(ctx, domid);
> >  
> > -        path = libxl__device_model_xs_path(gc, dm_domid, domid, "/state");
> > +        path = libxl__device_model_xs_path(gc, false, dm_domid, domid, "/state");
> >          state = libxl__xs_read(gc, XBT_NULL, path);
> >          if (state != NULL && !strcmp(state, "paused")) {
> >              libxl__qemu_traditional_cmd(gc, domid, "continue");
> > diff --git a/tools/libxl/libxl_create.c b/tools/libxl/libxl_create.c
> > index a74b340..df946e2 100644
> > --- a/tools/libxl/libxl_create.c
> > +++ b/tools/libxl/libxl_create.c
> > @@ -1002,6 +1002,9 @@ static void domcreate_bootloader_done(libxl__egc *egc,
> >          return;
> >      }
> >  
> > +    libxl__xs_write(gc, XBT_NULL, GCSPRINTF("/local/domain/%u/device-model", domid),
> > +            "%s", libxl__domain_device_model(gc, info));
> > +
> >      /* consume bootloader outputs. state->pv_{kernel,ramdisk} have
> >       * been initialised by the bootloader already.
> >       */
> > diff --git a/tools/libxl/libxl_device.c b/tools/libxl/libxl_device.c
> > index 93bb41e..aadcd08 100644
> > --- a/tools/libxl/libxl_device.c
> > +++ b/tools/libxl/libxl_device.c
> > @@ -1190,7 +1190,7 @@ int libxl__wait_for_device_model_deprecated(libxl__gc *gc,
> >      char *path;
> >      uint32_t dm_domid = libxl_get_stubdom_id(CTX, domid);
> >  
> > -    path = libxl__device_model_xs_path(gc, dm_domid, domid, "/state");
> > +    path = libxl__device_model_xs_path(gc, false, dm_domid, domid, "/state");
> >      return libxl__xenstore_child_wait_deprecated(gc, domid,
> >                                       LIBXL_DEVICE_MODEL_START_TIMEOUT,
> >                                       "Device Model", path, state, spawning,
> > diff --git a/tools/libxl/libxl_dm.c b/tools/libxl/libxl_dm.c
> > index bf77f50..7015729 100644
> > --- a/tools/libxl/libxl_dm.c
> > +++ b/tools/libxl/libxl_dm.c
> > @@ -1271,9 +1271,9 @@ void libxl__spawn_stub_dm(libxl__egc *egc, libxl__stub_dm_spawn_state *sdss)
> >  retry_transaction:
> >      t = xs_transaction_start(ctx->xsh);
> >      xs_mkdir(ctx->xsh, t,
> > -             libxl__device_model_xs_path(gc, dm_domid, guest_domid, ""));
> > +             libxl__device_model_xs_path(gc, false, dm_domid, guest_domid, ""));
> >      xs_set_permissions(ctx->xsh, t,
> > -                       libxl__device_model_xs_path(gc, dm_domid,
> > +                       libxl__device_model_xs_path(gc, false, dm_domid,
> >                                                     guest_domid, ""),
> >                         perm, ARRAY_SIZE(perm));
> >      if (!xs_transaction_end(ctx->xsh, t, 0))
> > @@ -1434,7 +1434,7 @@ static void stubdom_pvqemu_cb(libxl__egc *egc,
> >      sdss->xswait.what = GCSPRINTF("Stubdom %u for %u startup",
> >                                    dm_domid, sdss->dm.guest_domid);
> >      sdss->xswait.path =
> > -        libxl__device_model_xs_path(gc, dm_domid, sdss->dm.guest_domid,
> > +        libxl__device_model_xs_path(gc, true, dm_domid, sdss->dm.guest_domid,
> >                                      "/state");
> >      sdss->xswait.timeout_ms = LIBXL_STUBDOM_START_TIMEOUT * 1000;
> >      sdss->xswait.callback = stubdom_xswait_cb;
> > @@ -1570,7 +1570,8 @@ void libxl__spawn_local_dm(libxl__egc *egc, libxl__dm_spawn_state *dmss)
> >          free(path);
> >      }
> >  
> > -    path = libxl__device_model_xs_path(gc, LIBXL_TOOLSTACK_DOMID, domid, "");
> > +    path = libxl__device_model_xs_path(gc, b_info->type == LIBXL_DOMAIN_TYPE_PV,
> > +            LIBXL_TOOLSTACK_DOMID, domid, "");
> >      if (b_info->device_model_version == LIBXL_DEVICE_MODEL_VERSION_QEMU_XEN) {
> >          rwperm[0].id = LIBXL_TOOLSTACK_DOMID;
> >          rwperm[0].perms = XS_PERM_NONE;
> > @@ -1627,8 +1628,9 @@ retry_transaction:
> >          LIBXL__LOG(CTX, XTL_DEBUG, "  %s", *arg);
> >  
> >      spawn->what = GCSPRINTF("domain %d device model", domid);
> > -    spawn->xspath = libxl__device_model_xs_path(gc, LIBXL_TOOLSTACK_DOMID,
> > -                                                domid, "/state");
> > +    spawn->xspath = libxl__device_model_xs_path(gc,
> > +            b_info->type == LIBXL_DOMAIN_TYPE_PV, LIBXL_TOOLSTACK_DOMID,
> > +            domid, "/state");
> >      spawn->timeout_ms = LIBXL_DEVICE_MODEL_START_TIMEOUT * 1000;
> >      spawn->pidpath = GCSPRINTF("%s/image/device-model-pid", dom_path);
> >      spawn->midproc_cb = libxl__spawn_record_pid;
> > @@ -1761,7 +1763,7 @@ void libxl__spawn_qdisk_backend(libxl__egc *egc, libxl__dm_spawn_state *dmss)
> >      dmss->build_state->saved_state = 0;
> >  
> >      dmss->spawn.what = GCSPRINTF("domain %u Qdisk backend", domid);
> > -    dmss->spawn.xspath = GCSPRINTF("device-model/%u/state", domid);
> > +    dmss->spawn.xspath = libxl__device_model_xs_path(gc, true, 0, domid, "/state");
> >      dmss->spawn.timeout_ms = LIBXL_DEVICE_MODEL_START_TIMEOUT * 1000;
> >      /*
> >       * We cannot save Qemu pid anywhere in the xenstore guest dir,
> > @@ -1844,7 +1846,7 @@ out:
> >  
> >  int libxl__destroy_device_model(libxl__gc *gc, uint32_t domid)
> >  {
> > -    char *path = libxl__device_model_xs_path(gc, LIBXL_TOOLSTACK_DOMID,
> > +    char *path = libxl__device_model_xs_path(gc, false, LIBXL_TOOLSTACK_DOMID,
> >                                               domid, "");
> >      if (!xs_rm(CTX->xsh, XBT_NULL, path))
> >          LOG(ERROR, "xs_rm failed for %s", path);
> > diff --git a/tools/libxl/libxl_dom.c b/tools/libxl/libxl_dom.c
> > index 34b3c54..0f15a90 100644
> > --- a/tools/libxl/libxl_dom.c
> > +++ b/tools/libxl/libxl_dom.c
> > @@ -1016,7 +1016,7 @@ int libxl__qemu_traditional_cmd(libxl__gc *gc, uint32_t domid,
> >  {
> >      char *path = NULL;
> >      uint32_t dm_domid = libxl_get_stubdom_id(CTX, domid);
> > -    path = libxl__device_model_xs_path(gc, dm_domid, domid, "/command");
> > +    path = libxl__device_model_xs_path(gc, false, dm_domid, domid, "/command");
> >      return libxl__xs_write(gc, XBT_NULL, path, "%s", cmd);
> >  }
> >  
> > @@ -1034,7 +1034,7 @@ static inline char *restore_helper(libxl__gc *gc, uint32_t dm_domid,
> >                                     uint32_t domid,
> >                                     uint64_t phys_offset, char *node)
> >  {
> > -    return libxl__device_model_xs_path(gc, dm_domid, domid,
> > +    return libxl__device_model_xs_path(gc, false, dm_domid, domid,
> >                                         "/physmap/%"PRIx64"/%s",
> >                                         phys_offset, node);
> >  }
> > @@ -1146,9 +1146,9 @@ static void domain_suspend_switch_qemu_xen_traditional_logdirty
> >  
> >      if (!lds->cmd_path) {
> >          uint32_t dm_domid = libxl_get_stubdom_id(CTX, domid);
> > -        lds->cmd_path = libxl__device_model_xs_path(gc, dm_domid, domid,
> > +        lds->cmd_path = libxl__device_model_xs_path(gc, false, dm_domid, domid,
> >                                                      "/logdirty/cmd");
> > -        lds->ret_path = libxl__device_model_xs_path(gc, dm_domid, domid,
> > +        lds->ret_path = libxl__device_model_xs_path(gc, false, dm_domid, domid,
> >                                                      "/logdirty/ret");
> >      }
> >      lds->cmd = enable ? "enable" : "disable";
> > @@ -1672,7 +1672,7 @@ static inline char *physmap_path(libxl__gc *gc, uint32_t dm_domid,
> >                                   uint32_t domid,
> >                                   char *phys_offset, char *node)
> >  {
> > -    return libxl__device_model_xs_path(gc, dm_domid, domid,
> > +    return libxl__device_model_xs_path(gc, false, dm_domid, domid,
> >                                         "/physmap/%s/%s",
> >                                         phys_offset, node);
> >  }
> > @@ -1696,7 +1696,7 @@ int libxl__toolstack_save(uint32_t domid, uint8_t **buf,
> >      dm_domid = libxl_get_stubdom_id(CTX, domid);
> >  
> >      entries = libxl__xs_directory(gc, 0,
> > -                libxl__device_model_xs_path(gc, dm_domid, domid, "/physmap"),
> > +                libxl__device_model_xs_path(gc, false, dm_domid, domid, "/physmap"),
> >                  &num);
> >      count = num;
> >  
> > diff --git a/tools/libxl/libxl_internal.c b/tools/libxl/libxl_internal.c
> > index c2c67bd..5836742 100644
> > --- a/tools/libxl/libxl_internal.c
> > +++ b/tools/libxl/libxl_internal.c
> > @@ -567,14 +567,25 @@ void libxl__update_domain_configuration(libxl__gc *gc,
> >      dst->b_info.video_memkb = src->b_info.video_memkb;
> >  }
> >  
> > -char *libxl__device_model_xs_path(libxl__gc *gc, uint32_t dm_domid,
> > +char *libxl__device_model_xs_path(libxl__gc *gc, bool pvqemu, uint32_t dm_domid,
> >                                    uint32_t domid, const char *format,  ...)
> >  {
> >      char *s, *fmt;
> >      va_list ap;
> > -
> > -    fmt = GCSPRINTF("/local/domain/%u/device-model/%u%s", dm_domid,
> > -                    domid, format);
> > +    char *dm;
> > +    int emulator_id = 0;
> > +
> > +    dm = libxl__xs_read(gc, XBT_NULL, GCSPRINTF("/local/domain/%u/device-model", domid));
> > +    if (dm)
> > +        emulator_id = libxl__check_qemu_supported(gc, dm, "emulator_id");
> > +
> > +    if (!emulator_id) {
> > +        fmt = GCSPRINTF("/local/domain/%u/device-model/%u%s", dm_domid,
> > +                domid, format);
> > +    } else {
> > +        fmt = GCSPRINTF("/local/domain/%u/device-model/%u/%u%s", dm_domid,
> > +                domid, pvqemu ? QEMU_XEN_PV_ID : QEMU_XEN_DEVICE_MODEL_ID, format);
> > +    }
> >  
> >      va_start(ap, format);
> >      s = libxl__vsprintf(gc, fmt, ap);
> > diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
> > index b4bae2f..e15cdc7 100644
> > --- a/tools/libxl/libxl_internal.h
> > +++ b/tools/libxl/libxl_internal.h
> > @@ -1830,9 +1830,8 @@ _hidden libxl__json_object *libxl__json_parse(libxl__gc *gc_opt, const char *s);
> >  _hidden int libxl__device_model_version_running(libxl__gc *gc, uint32_t domid);
> >    /* Return the system-wide default device model */
> >  _hidden libxl_device_model_version libxl__default_device_model(libxl__gc *gc);
> > -_hidden char *libxl__device_model_xs_path(libxl__gc *gc, uint32_t dm_domid,
> > -                                          uint32_t domid,
> > -                                          const char *format, ...) PRINTF_ATTRIBUTE(4, 5);
> > +_hidden char *libxl__device_model_xs_path(libxl__gc *gc, bool pvqemu, uint32_t dm_domid,
> > +                                  uint32_t domid, const char *format,  ...);
> >  
> >  /* Check how executes hotplug script currently */
> >  int libxl__hotplug_settings(libxl__gc *gc, xs_transaction_t t);
> > diff --git a/tools/libxl/libxl_pci.c b/tools/libxl/libxl_pci.c
> > index e0743f8..07f6209 100644
> > --- a/tools/libxl/libxl_pci.c
> > +++ b/tools/libxl/libxl_pci.c
> > @@ -853,9 +853,9 @@ static int qemu_pci_add_xenstore(libxl__gc *gc, uint32_t domid,
> >      uint32_t dm_domid;
> >  
> >      dm_domid = libxl_get_stubdom_id(CTX, domid);
> > -    path = libxl__device_model_xs_path(gc, dm_domid, domid, "/state");
> > +    path = libxl__device_model_xs_path(gc, false, dm_domid, domid, "/state");
> >      state = libxl__xs_read(gc, XBT_NULL, path);
> > -    path = libxl__device_model_xs_path(gc, dm_domid, domid, "/parameter");
> > +    path = libxl__device_model_xs_path(gc, false, dm_domid, domid, "/parameter");
> >      if (pcidev->vdevfn) {
> >          libxl__xs_write(gc, XBT_NULL, path, PCI_BDF_VDEVFN","PCI_OPTIONS,
> >                          pcidev->domain, pcidev->bus, pcidev->dev,
> > @@ -870,9 +870,9 @@ static int qemu_pci_add_xenstore(libxl__gc *gc, uint32_t domid,
> >      libxl__qemu_traditional_cmd(gc, domid, "pci-ins");
> >      rc = libxl__wait_for_device_model_deprecated(gc, domid, NULL, NULL,
> >                                        pci_ins_check, state);
> > -    path = libxl__device_model_xs_path(gc, dm_domid, domid, "/parameter");
> > +    path = libxl__device_model_xs_path(gc, false, dm_domid, domid, "/parameter");
> >      vdevfn = libxl__xs_read(gc, XBT_NULL, path);
> > -    path = libxl__device_model_xs_path(gc, dm_domid, domid, "/state");
> > +    path = libxl__device_model_xs_path(gc, false, dm_domid, domid, "/state");
> >      if ( rc < 0 )
> >          LIBXL__LOG(ctx, LIBXL__LOG_ERROR,
> >                     "qemu refused to add device: %s", vdevfn);
> > @@ -1178,9 +1178,9 @@ static int qemu_pci_remove_xenstore(libxl__gc *gc, uint32_t domid,
> >  
> >      dm_domid = libxl_get_stubdom_id(CTX, domid);
> >  
> > -    path = libxl__device_model_xs_path(gc, dm_domid, domid, "/state");
> > +    path = libxl__device_model_xs_path(gc, false, dm_domid, domid, "/state");
> >      state = libxl__xs_read(gc, XBT_NULL, path);
> > -    path = libxl__device_model_xs_path(gc, dm_domid, domid, "/parameter");
> > +    path = libxl__device_model_xs_path(gc, false, dm_domid, domid, "/parameter");
> >      libxl__xs_write(gc, XBT_NULL, path, PCI_BDF, pcidev->domain,
> >                      pcidev->bus, pcidev->dev, pcidev->func);
> >  
> > @@ -1198,7 +1198,7 @@ static int qemu_pci_remove_xenstore(libxl__gc *gc, uint32_t domid,
> >              return ERROR_FAIL;
> >          }
> >      }
> > -    path = libxl__device_model_xs_path(gc, dm_domid, domid, "/state");
> > +    path = libxl__device_model_xs_path(gc, false, dm_domid, domid, "/state");
> >      xs_write(ctx->xsh, XBT_NULL, path, state, strlen(state));
> >  
> >      return 0;
> 
>