[libvirt] [PATCH] qemu: Increase RLIMIT_MEMLOCK when memoryBacking/locked is used
If a domain is configured to have all its memory locked, we need to
increase RLIMIT_MEMLOCK so that QEMU is actually allowed to lock the
memory.
---
src/qemu/qemu_command.c | 31 +++++++++++++++++++++----------
1 file changed, 21 insertions(+), 10 deletions(-)
diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index c268a3a..8e2de09 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -6440,6 +6440,7 @@ qemuBuildCommandLine(virConnectPtr conn,
int spice = 0;
int usbcontroller = 0;
bool usblegacy = false;
+ bool mlock;
int contOrder[] = {
/* We don't add an explicit IDE or FD controller because the
* provided PIIX4 device already includes one. It isn't possible to
@@ -6551,6 +6552,7 @@ qemuBuildCommandLine(virConnectPtr conn,
virCommandAddArgFormat(cmd, "mlock=%s",
def->mem.locked ? "on" : "off");
}
+ mlock = def->mem.locked;
virCommandAddArg(cmd, "-smp");
if (!(smp = qemuBuildSmpArgStr(def, qemuCaps)))
@@ -8191,22 +8193,13 @@ qemuBuildCommandLine(virConnectPtr conn,
if (hostdev->source.subsys.u.pci.backend
== VIR_DOMAIN_HOSTDEV_PCI_BACKEND_VFIO) {
- unsigned long long memKB;
-
if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE_VFIO_PCI)) {
virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
_("VFIO PCI device assignment is not "
"supported by this version of qemu"));
goto error;
}
- /* VFIO requires all of the guest's memory to be
- * locked resident, plus some amount for IO
- * space. Alex Williamson suggested adding 1GiB for IO
- * space just to be safe (some finer tuning might be
- * nice, though).
- */
- memKB = def->mem.max_balloon + (1024 * 1024);
- virCommandSetMaxMemLock(cmd, memKB * 1024);
+ mlock = true;
}
if (virQEMUCapsGet(qemuCaps, QEMU_CAPS_DEVICE)) {
@@ -8425,6 +8418,24 @@ qemuBuildCommandLine(virConnectPtr conn,
goto error;
}
+ if (mlock) {
+ unsigned long long memKB;
+ /* VFIO requires all of the guest's memory to be locked resident,
+ * plus some amount for IO space. Alex Williamson suggested
+ * adding 1GiB for IO space just to be safe (some finer tuning
+ * might be nice, though).
+ *
+ * If memory hard_limit is configured, we can use it directly as
+ * there is no sense to set MEMLOCK limit beyond it. Also we can
+ * safely use it instead of any magically computed value.
+ */
+ if (def->mem.hard_limit)
+ memKB = def->mem.hard_limit;
+ else
+ memKB = def->mem.max_balloon + (1024 * 1024);
+ virCommandSetMaxMemLock(cmd, memKB * 1024);
+ }
+
virObjectUnref(cfg);
return cmd;
--
1.8.2.1