Re: [PATCH: kvm 3/5] Fix hotadd of CPUs for KVM.

Zachary Amsden
2009-09-28T01:42:00Z

On 09/26/2009 10:52 PM, Avi Kivity wrote:
> On 09/25/2009 03:47 AM, Zachary Amsden wrote:
>>
>> --- a/virt/kvm/kvm_main.c
>> +++ b/virt/kvm/kvm_main.c
>> @@ -1716,9 +1716,6 @@ static int kvm_cpu_hotplug(struct
>> notifier_block *notifier, unsigned long val,
>> {
>> int cpu = (long)v;
>>
>> - if (!kvm_usage_count)
>> - return NOTIFY_OK;
>> -
>
> Why? You'll now do hardware_enable() even if kvm is not in use.

Because otherwise you'll never allocate and hardware_enable_all will fail:

Switch to broadcast mode on CPU1
svm_hardware_enable: svm_data is NULL on 1
kvm: enabling virtualization on CPU1 failed
qemu-system-x86[8698]: segfault at 20 ip 00000000004db22f sp
00007fff0a3b4560 error 6 in qemu-system-x86_64[400000+21f000]

Perhaps I can make this work better by putting the allocation within
hardware_enable_all.

Zach