Re: [PATCH v2 9/9] qemu: Place helper processes into the same trusted group

Since the level of trust that QEMU has is the same level of trust that helper processes have there's no harm in placing all of them into the same group. Unfortunately, since these processes are started before QEMU we can't use brand new virCommand*() APIs (those are used on hotplug though) and have to use the low level virProcess*() APIs. Moreover, because there no (kernel) API that would copy cookie from one process to another WITHOUT modifying the cookie of the process that's doing the copy, we have to fork() and use available copy APIs. Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; --- src/qemu/qemu_extdevice.c | 120 ++++++++++++++++++++++++++++++++++++++ src/qemu/qemu_extdevice.h | 3 + src/qemu/qemu_process.c | 4 ++ 3 files changed, 127 insertions(+) diff --git a/src/qemu/qemu_extdevice.c b/src/qemu/qemu_extdevice.c index b8e3c1000a..41368a9cea 100644 --- a/src/qemu/qemu_extdevice.c +++ b/src/qemu/qemu_extdevice.c @@ -335,3 +335,123 @@ qemuExtDevicesSetupCgroup(virQEMUDriver *driver, return 0; } + + +static int +qemuExtDevicesSetupSchedHelper(pid_t ppid G_GNUC_UNUSED, + void *opaque) +{ + GSList *pids = opaque; + GSList *next; + pid_t vmPid; + + /* The first item on the list is special: it's the PID of the + * QEMU that has the cookie we want to copy to the rest. */ + vmPid = GPOINTER_TO_INT(pids->data); + if (virProcessSchedCoreShareFrom(vmPid) < 0) { + virReportSystemError(errno, + _("Unable to get core group of: %lld"), + (long long) vmPid); + return -1; + } + + VIR_DEBUG("SCHED_CORE: vmPid = %lld", (long long) vmPid); + + for (next = pids->next; next; next = next->next) { + pid_t pid = GPOINTER_TO_INT(next->data); + + VIR_DEBUG("SCHED_CORE: share to %lld", (long long) pid); + if (virProcessSchedCoreShareTo(pid) < 0) { + virReportSystemError(errno, + _("Unable to share core group to: %lld"), + (long long) pid); + return -1; + } + }