I traced the qemu process, and find out that host cpuid doesn't
support x2apic,
but VM interception seems enabled x2apic.
with function=1(bit 21 indicates x2apic)
host_cpuid:ecx=0x009ce3bd
guest_cpuid:ecx=0x00b82201
On 2013-07-22 19:24, Peter Huang(Peng) wrote:
Hi, Everyone
I have been encountered a problem recently.
My box uses Nehalem E5520 CPU, and this model doesn't support
x2apic feature.
I created a VM on KVM, and uses cpu mode=pass-through, I can get
the right cpu
model from the VM, but I can also see that the CPU in the vm
supports x2apic.
This seems werid.
From QEMU's CPU model definition, Nehalem also doesn't support
x2apic.
Can anyone explain it?
Thanks to you all!
Below is the cpuinfo from host and guest:
host:
fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
mca cmov pat pse36 clflush
dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp lm
constant_tsc
arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc
aperfmperf pni dtes64
monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm dca sse4_1 sse4_2
popcnt lahf_lm dtherm tpr_shadow vnmi flexpriority ept vpid
vm:
fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat
pse36 clflush
mmx fxsr sse sse2 ss ht syscall nx rdtscp lm constant_tsc
arch_perfmon rep_good
nopl pni ssse3 cx16 sse4_1 sse4_2 x2apic popcnt
hypervisor lahf_lm