On Wed, Jul 24, 2013 at 12:02:46PM +0200, Igor Mammedov wrote: > On Wed, 24 Jul 2013 17:52:50 +0800 > Hu Tao <hu...@cn.fujitsu.com> wrote: > > > v6 doesn't work here, things are going fine until online hotplugged > > memory in guest. > > > > steps: > > > > 1. qemu cmd: > > > > ./x86_64-softmmu/qemu-system-x86_64 -enable-kvm -m 512,maxmem=2G,slots=1 \ > > -hda /mnt/data/libvirt-images/hut-rhel6.3.img -L ../pc-bios-memhp/ > > > > (bios is from MST's acpi tree) > > > > 2. hot-plug a dimm: > > > > device_adddimm,id=d0,size=1G > > > > 3. online hotplugged memory(in guest): > > > > echo 'onlone' > /sys/devices/system/memory/memory/32/state > > > > then after several seconds the console prints error messages like: > > > > nommu_map_sg: overflow 107c15000+4096 of device mask ffffffff > > ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0 > > ata1.00: cmd ca/00:10:d0:0d:a4/00:00:00:00:00/e0 tag 0 dma 8192 out > > res 50/00:00:08:09:e0/00:00:00:00:00/e0 Emask 0x40 (internal > > error) > > ata1.00: configured for MWDMA2 > > ata1: EH complete > > > > (repeat) > > > > and can't do any disk I/O. > Looks like a guest bug where it tries to use high memory but assumes low one.
yes. Iirc booting the guest kernel with "swiotlb=force" option could also work around this. > if you boot guest with initial memory 4Gb then it wont hit issue or use FC18 > which doesn't have this problem. thanks, - Vasilis