Re: [libvirt] [PATCH 1/3] qemu: implement qemu's dump-guest-memory

On 04/20/2012 09:27 AM, Wen Congyang wrote: > dump-guest-memory is a new dump mechanism, and it can work when the > guest uses host devices. This patch adds a API to use this new > monitor command. > > --- > src/qemu/qemu_monitor.c | 38 ++++++++++++++++++++++++++++++++++++++ > src/qemu/qemu_monitor.h | 12 ++++++++++++ > src/qemu/qemu_monitor_json.c | 34 ++++++++++++++++++++++++++++++++++ > src/qemu/qemu_monitor_json.h | 6 ++++++ > 4 files changed, 90 insertions(+), 0 deletions(-) > > diff --git a/src/qemu/qemu_monitor.c b/src/qemu/qemu_monitor.c > index 2f66c46..a5d3eec 100644 > --- a/src/qemu/qemu_monitor.c > +++ b/src/qemu/qemu_monitor.c > @@ -2018,6 +2018,44 @@ int qemuMonitorMigrateCancel(qemuMonitorPtr mon) > return ret; > } > > +int qemuMonitorDumpToFd(qemuMonitorPtr mon, > + unsigned int flags, > + int fd, > + unsigned long long begin, > + unsigned long long length) > +{ > + int ret; > + VIR_DEBUG("mon=%p fd=%d flags=%x begin=%llx length=%llx", > + mon, fd, flags, begin, length); > + > + if (!mon) { > + qemuReportError(VIR_ERR_INVALID_ARG, "%s", > + _("monitor must not be NULL")); > + return -1; > + } > + > + if (!mon->json) { > + /* dump-guest-memory is supported after qemu-1.0, and we always use json > + * if qemu's version is >= 0.15. So if we use text mode, the qemu is > + * old, and it does not support dump-guest-memory. > + */ > + qemuReportError(VIR_ERR_NO_SUPPORT, "%s", > + _("dump-guest-memory is not supported in text mode")); > + return -1; > + } Correct me if I'm wrong, but shouldn't this be rather handled by adding it as a qemu capability? Maybe by checking the qemu version in qemuCapsComputeCmdFlags()? Or probably even better by checking that command in qemuCapsComputeCmdFlags(). That way we can be sure that the command is supported.