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

At 05/23/2012 04:56 PM, Martin Kletzander Wrote: > 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. > If mon->json is false, we use the text mode, so the qemu's version is < 0.15. The dump-guest-memory is supported after qemu-1.0. So we can say that the qemu does not support dump-guest-memory if mon->json is false. Thanks Wen Congyang