From: Andrea Bolognani <abologna@redhat.com>
Date: Wed, 22 Mar 2017 12:44:13 +0000 (+0100)
Subject: qemu: Fix memory locking limit calculation
X-Git-Tag: v3.2.0-rc2~17
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7e667664d28f90bf6916604a55ebad7e2d85305b;p=thirdparty%2Flibvirt.git

qemu: Fix memory locking limit calculation

For guests that use <memoryBacking><locked>, our only option
is to remove the memory locking limit altogether.

Partially-resolves: https://bugzilla.redhat.com/1431793
---

diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c
index ed7f199143..458bb5f9a4 100644
--- a/src/qemu/qemu_domain.c
+++ b/src/qemu/qemu_domain.c
@@ -6223,10 +6223,13 @@ qemuDomainGetMemLockLimitBytes(virDomainDefPtr def)
         goto done;
     }
 
-    if (def->mem.locked) {
-        memKB = virDomainDefGetMemoryTotal(def) + 1024 * 1024;
-        goto done;
-    }
+    /* If the guest wants its memory to be locked, we need to raise the memory
+     * locking limit so that the OS will not refuse allocation requests;
+     * however, there is no reliable way for us to figure out how much memory
+     * the QEMU process will allocate for its own use, so our only way out is
+     * to remove the limit altogether. Use with extreme care */
+    if (def->mem.locked)
+        return VIR_DOMAIN_MEMORY_PARAM_UNLIMITED;
 
     if (ARCH_IS_PPC64(def->os.arch) && def->virtType == VIR_DOMAIN_VIRT_KVM) {
         unsigned long long maxMemory;