From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:52554) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aiLKR-0001lH-Ry for qemu-devel@nongnu.org; Tue, 22 Mar 2016 08:22:32 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aiLKO-0006dP-Fe for qemu-devel@nongnu.org; Tue, 22 Mar 2016 08:22:31 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46673) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aiLKO-0006d8-89 for qemu-devel@nongnu.org; Tue, 22 Mar 2016 08:22:28 -0400 Date: Tue, 22 Mar 2016 12:22:22 +0000 From: "Dr. David Alan Gilbert" Message-ID: <20160322122222.GE2216@work-vm> References: <1457942602-1274-1-git-send-email-xiecl.fnst@cn.fujitsu.com> <1457942602-1274-2-git-send-email-xiecl.fnst@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1457942602-1274-2-git-send-email-xiecl.fnst@cn.fujitsu.com> Subject: Re: [Qemu-devel] [PATCH v2 1/1] Introduce "xen-load-devices-state" List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Changlong Xie Cc: zhanghailiang , Juan Quintela , Stefano Stabellini , qemu devel , Markus Armbruster , Amit Shah , Anthony PERARD * Changlong Xie (xiecl.fnst@cn.fujitsu.com) wrote: > From: Wen Congyang > > Introduce a "xen-load-devices-state" QAPI command that can be used to > load the state of all devices, but not the RAM or the block devices of > the VM. > > We only have hmp commands savevm/loadvm, and qmp commands > xen-save-devices-state. Can you explain on Xen how the RAM actually gets loaded? > > We use this new command for COLO: > 1. suspend both primary vm and secondary vm > 2. sync the state > 3. resume both primary vm and secondary vm > > In such case, we need to update all devices' state in any time. > > Signed-off-by: Wen Congyang > Signed-off-by: Changlong Xie > --- > migration/savevm.c | 36 ++++++++++++++++++++++++++++++++++++ > qapi-schema.json | 14 ++++++++++++++ > qmp-commands.hx | 27 +++++++++++++++++++++++++++ > 3 files changed, 77 insertions(+) > > diff --git a/migration/savevm.c b/migration/savevm.c > index 96e7db5..aaead12 100644 > --- a/migration/savevm.c > +++ b/migration/savevm.c > @@ -50,6 +50,7 @@ > #include "qemu/iov.h" > #include "block/snapshot.h" > #include "block/qapi.h" > +#include "hw/xen/xen.h" > > > #ifndef ETH_P_RARP > @@ -1768,6 +1769,12 @@ qemu_loadvm_section_start_full(QEMUFile *f, MigrationIncomingState *mis) > return -EINVAL; > } > > + /* Validate if it is a device's state */ > + if (xen_enabled() && se->is_ram) { > + error_report("loadvm: %s RAM loading not allowed on Xen", idstr); > + return -EINVAL; > + } > + > /* Add entry */ > le = g_malloc0(sizeof(*le)); > > @@ -2077,6 +2084,35 @@ void qmp_xen_save_devices_state(const char *filename, Error **errp) > } > } > > +void qmp_xen_load_devices_state(const char *filename, Error **errp) > +{ > + QEMUFile *f; > + int saved_vm_running; > + int ret; > + > + saved_vm_running = runstate_is_running(); > + vm_stop(RUN_STATE_RESTORE_VM); > + > + f = qemu_fopen(filename, "rb"); > + if (!f) { > + error_setg_file_open(errp, errno, filename); > + goto out; > + } > + > + migration_incoming_state_new(f); > + ret = qemu_loadvm_state(f); > + qemu_fclose(f); > + migration_incoming_state_destroy(); > + if (ret < 0) { > + error_setg(errp, QERR_IO_ERROR); > + } > + > +out: > + if (saved_vm_running) { > + vm_start(); > + } Does it ever happen that you had it running immediately before you did this command? Somehow you'd have to have loaded the RAM at just the right point, and I don't see how that would happen if the guest was running. Dave > +} > + > int load_vmstate(const char *name) > { > BlockDriverState *bs, *bs_vm_state; > diff --git a/qapi-schema.json b/qapi-schema.json > index 362c9d8..8cca59d 100644 > --- a/qapi-schema.json > +++ b/qapi-schema.json > @@ -4122,3 +4122,17 @@ > ## > { 'enum': 'ReplayMode', > 'data': [ 'none', 'record', 'play' ] } > + > +## > +# @xen-load-devices-state: > +# > +# Load the state of all devices from file. The RAM and the block devices > +# of the VM are not loaded by this command. > +# > +# @filename: the file to load the state of the devices from as binary > +# data. See xen-save-devices-state.txt for a description of the binary > +# format. > +# > +# Since: 2.7 > +## > +{ 'command': 'xen-load-devices-state', 'data': {'filename': 'str'} } > diff --git a/qmp-commands.hx b/qmp-commands.hx > index b629673..4925702 100644 > --- a/qmp-commands.hx > +++ b/qmp-commands.hx > @@ -587,6 +587,33 @@ Example: > EQMP > > { > + .name = "xen-load-devices-state", > + .args_type = "filename:F", > + .mhandler.cmd_new = qmp_marshal_xen_load_devices_state, > + }, > + > +SQMP > +xen-load-devices-state > +---------------------- > + > +Load the state of all devices from file. The RAM and the block devices > +of the VM are not loaded by this command. > + > +Arguments: > + > +- "filename": the file to load the state of the devices from as binary > +data. See xen-save-devices-state.txt for a description of the binary > +format. > + > +Example: > + > +-> { "execute": "xen-load-devices-state", > + "arguments": { "filename": "/tmp/resume" } } > +<- { "return": {} } > + > +EQMP > + > + { > .name = "xen-set-global-dirty-log", > .args_type = "enable:b", > .mhandler.cmd_new = qmp_marshal_xen_set_global_dirty_log, > -- > 1.9.3 > > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK