I have same problem with wheezy
(host) and squeeze (guest).
In libvirt I have following memory configuration for the guest: <memory unit='MiB'>1024</memory> <currentMemory unit='MiB'>128</currentMemory> [...] <memballoon model='virtio'> <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/> </memballoon> But the guest uses only 128 Mb, and when it fills, begins to use swap instead of increase memory. Linux version 3.2.0-4-amd64 (debian-kernel@lists.debian.org) (gcc version 4.6.3 (Debian 4.6.3-15) ) #1 SMP Debian 3.2.41-2 Command line: BOOT_IMAGE=/boot/vmlinuz-3.2.0-4-amd64 root=UUID=170b7f1f-8fd8-4e89-b923-b8ecfa50d761 ro quiet Packages: libvirt-bin 0.9.12-11 amd64 libvirt0 0.9.12-11 amd64 python-libvirt 0.9.12-11 amd64 qemu-kvm 1.1.2+dfsg-6 amd64 virt-viewer 0.5.3-1 amd64 virtinst 0.600.1-3 all lspci: 00:00.0 Host bridge: Intel Corporation Xeon E3-1200 v2/3rd Gen Core processor DRAM Controller (rev 09) 00:01.0 PCI bridge: Intel Corporation Xeon E3-1200 v2/3rd Gen Core processor PCI Express Root Port (rev 09) 00:02.0 VGA compatible controller: Intel Corporation Xeon E3-1200 v2/3rd Gen Core processor Graphics Controller (rev 09) 00:14.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset Family USB xHCI Host Controller (rev 04) 00:16.0 Communication controller: Intel Corporation 7 Series/C210 Series Chipset Family MEI Controller #1 (rev 04) 00:1a.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset Family USB Enhanced Host Controller #2 (rev 04) 00:1b.0 Audio device: Intel Corporation 7 Series/C210 Series Chipset Family High Definition Audio Controller (rev 04) 00:1c.0 PCI bridge: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 1 (rev c4) 00:1c.5 PCI bridge: Intel Corporation 7 Series/C210 Series Chipset Family PCI Express Root Port 6 (rev c4) 00:1c.6 PCI bridge: Intel Corporation 82801 PCI Bridge (rev c4) 00:1d.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset Family USB Enhanced Host Controller #1 (rev 04) 00:1f.0 ISA bridge: Intel Corporation Z77 Express Chipset LPC Controller (rev 04) 00:1f.2 SATA controller: Intel Corporation 7 Series/C210 Series Chipset Family 6-port SATA Controller [AHCI mode] (rev 04) 00:1f.3 SMBus: Intel Corporation 7 Series/C210 Series Chipset Family SMBus Controller (rev 04) 03:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168B PCI Express Gigabit Ethernet controller (rev 09) 04:00.0 PCI bridge: ASMedia Technology Inc. ASM1083/1085 PCIe to PCI Bridge (rev 03) Modules: tun ip6table_filter ip6_tables ebtable_nat ebtables bridge stp ipt_MASQUERADE xt_conntrack xt_tcpudp iptable_mangle iptable_filter iptable_nat nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_conntrack ip_tables x_tables 6_tables,ip6table_filter loop kvm_intel kvm snd_hda_codec_hdmi snd_hda_codec_realtek joydev usbhid hid snd_hda_intel snd_hda_codec snd_hwdep i915 snd_pcm snd_page_alloc snd_timer snd soundcore drm_kms_helper drm eeepc_wmi psmouse i2c_algo_bit coretemp acpi_cpufreq mperf pcspkr asus_wmi sparse_keymap rfkill serio_raw evdev crc32c_intel ghash_clmulni_intel cryptd mxm_wmi i2c_i801 i2c_core video processor iTCO_wdt iTCO_vendor_support wmi button ext3 mbcache jbd dm_mod raid1 md_mod sg sd_mod crc_t10dif fan thermal thermal_sys ahci r8169 libahci mii libata scsi_mod ehci_hcd xhci_hcd usbcore usb_common |