Re: [libvirt] [PATCH] libxl: support dom0

In Xen, dom0 is really just another domain that supports ballooning, adding/removing devices, changing vcpu configuration, etc. This patch adds support to the libxl driver for managing dom0. Note that the legacy xend driver has long supported managing dom0. Operations that are not supported on dom0 are filtered in libvirt where a sensible error is reported. Errors from libxl are not always helpful. E.g., attempting a save on dom0 results in 2015-06-23 15:25:05 MDT libxl: debug: libxl_dom.c:1570:libxl__toolstack_save: domain=0 toolstack data size=8 2015-06-23 15:25:05 MDT libxl: debug: libxl.c:979:do_libxl_domain_suspend: ao 0x7f7e68000b70: inprogress: poller=0x7f7e68000930, flags=i 2015-06-23 15:25:05 MDT libxl-save-helper: debug: starting save: Success 2015-06-23 15:25:05 MDT xc: detail: xc_domain_save_suse: starting save of domid 0 2015-06-23 15:25:05 MDT xc: error: Couldn't map live_shinfo (3 = No such process): Internal error 2015-06-23 15:25:05 MDT xc: detail: Save exit of domid 0 with errno=3 2015-06-23 15:25:05 MDT libxl-save-helper: debug: complete r=1: No such process 2015-06-23 15:25:05 MDT libxl: error: libxl_dom.c:1876:libxl__xc_domain_save_done: saving domain: domain did not respond to suspend request: No such process 2015-06-23 15:25:05 MDT libxl: error: libxl_dom.c:2033:remus_teardown_done: Remus: failed to teardown device for guest with domid 0, rc -8 Signed-off-by: Jim Fehlig <jfehlig(a)suse.com&gt; --- src/libxl/libxl_driver.c | 95 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 95 insertions(+) diff --git a/src/libxl/libxl_driver.c b/src/libxl/libxl_driver.c index 149ef70..d0b76ac 100644 --- a/src/libxl/libxl_driver.c +++ b/src/libxl/libxl_driver.c @@ -79,6 +79,15 @@ VIR_LOG_INIT("libxl.libxl_driver"); /* Number of Xen scheduler parameters */ #define XEN_SCHED_CREDIT_NPARAM 2 +#define LIBXL_CHECK_DOM0_GOTO(name, label) \ + do { \ + if (STREQ_NULLABLE(name, "Domain-0")) { \ + virReportError(VIR_ERR_OPERATION_INVALID, "%s", \ + _("Domain-0 does not support requested operation")); \ + goto label; \ + } \ + } while (0) + static libxlDriverPrivatePtr libxl_driver; @@ -501,6 +510,62 @@ const struct libxl_event_hooks ev_hooks = { }; static int +libxlAddDom0(libxlDriverPrivatePtr driver) +{ + libxlDriverConfigPtr cfg = libxlDriverConfigGet(driver); + virDomainDefPtr def = NULL; + virDomainObjPtr vm = NULL; + virDomainDefPtr oldDef = NULL; + libxl_dominfo d_info; + int ret = -1; + + libxl_dominfo_init(&d_info); + + /* Ensure we have a dom0 */ + if (libxl_domain_info(cfg->ctx, &d_info, 0) != 0) { + virReportError(VIR_ERR_INTERNAL_ERROR, + "%s", _("unable to get Domain-0 information from libxenlight")); + goto cleanup; + } + + if (!(def = virDomainDefNew())) + goto cleanup; + + def->id = 0; + def->virtType = VIR_DOMAIN_VIRT_XEN; + if (VIR_STRDUP(def->name, "Domain-0") < 0) + goto cleanup; + + def->os.type = VIR_DOMAIN_OSTYPE_XEN; + + if (virUUIDParse("00000000-0000-0000-0000-000000000000", def->uuid) < 0) + goto cleanup; + + vm->def->vcpus = d_info.vcpu_online; + vm->def->maxvcpus = d_info.vcpu_max_id + 1; + vm->def->mem.cur_balloon = d_info.current_memkb; + vm->def->mem.max_balloon = d_info.max_memkb;

+ + if (!(vm = virDomainObjListAdd(driver->domains, def, + driver->xmlopt, + 0, + &oldDef))) + goto cleanup; + + def = NULL; + ret = 0;