Hi all,

There is a error when I install a RHEL or FC17 os on my nest-kvm.

I find some error in the qemu log( attachment) as follow:
KVM: entry failed, hardware error 0x7


so I check the related code in kvm.c.

int kvm_arch_handle_exit(CPUX86State *env, struct kvm_run *run)
{
uint64_t code;
int ret;

switch (run->exit_reason) {
...
case KVM_EXIT_FAIL_ENTRY:
code = run->fail_entry.hardware_entry_failure_reason;
fprintf(stderr, "KVM: entry failed, hardware error 0x%" PRIx64 "\n",
code);
if (host_supports_vmx() && code == VMX_INVALID_GUEST_STATE) {
fprintf(stderr,
"\nIf you're running a guest on an Intel machine without "
"unrestricted mode\n"
"support, the failure can be most likely due to the guest "
"entering an invalid\n"
"state for Intel VT. For example, the guest maybe running "
"in big real mode\n"
"which is not supported on less recent Intel processors."
"\n\n");
}
ret = -1;
break;
case KVM_EXIT_EXCEPTION:
...
}

 From the code, I'm not sure error is caused by nest kvm.
for the hardware_entry_failure_reason is 0x7 not VMX_INVALID_GUEST_STATE.
but I'm not find where the hardware_entry_failure_reason is set. I doubt 
it is set by KVM module in kernel.

here is the environment:
the guest hypervisor, a nest-kvm VM, OS is 3.6.1-1.fc17.x86_64. And it 
does support VT.
$ sudo cat /proc/cpuinfo |grep vmx
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
mca cmov pat pse36 clflush mmx fxsr sse sse2 ss syscall nx pdpe1gb
rdtscp lm constant_tsc arch_perfmon rep_good nopl pni pclmulqdq vmx
ssse3 cx16 sse4_1 sse4_2 popcnt aes hypervisor lahf_lm

The host: OS is 3.6.1-1.fc17.x86_64. CPU is Intel(R) Xeon(R) CPU X5650. 
The host also opens the nested switch.
$ cat /sys/module/kvm_intel/parameters/nested
Y

-- 
Sheldon Feng(冯少合)<shaohef@linux.vnet.ibm.com>
IBM Linux Technology Center