On 02/17/2017 at 05:07 PM, Borislav Petkov wrote:
> On Fri, Feb 17, 2017 at 09:53:21AM +0800, Xunlei Pang wrote:
>> It changes the value of cpu_online_mask/etc which will cause confusion to vmcore analysis.
> Then export the crashing_cpu variable, initialize it to something
> invalid in the first kernel, -1 for example, and test it in the #MC
> handlier like this:
>
> int cpu;
>
> ...
>
> cpu = smp_processor_id();
>
> if (cpu_is_offline(cpu) ||
> ((crashing_cpu != -1) && (crashing_cpu != cpu)) {
> u64 mcgstatus;
>
> mcgstatus = mce_rdmsrl(MSR_IA32_MCG_STATUS);
> if (mcgstatus & MCG_STATUS_RIPV) {
> mce_wrmsrl(MSR_IA32_MCG_STATUS, 0);
> return;
> }
> }
Yes, it is doable, I will do some tests later.
>> Moreover, for the code(see comment inlined)
>>
>> if (cpu_is_offline(smp_processor_id())) {
>> u64 mcgstatus;
>>
>> mcgstatus = mce_rdmsrl(MSR_IA32_MCG_STATUS);
>> if (mcgstatus & MCG_STATUS_RIPV) { // This condition may be not true, the mce triggered on kdump cpu
>> // doesn't need to have this bit set for the other cpus remain in 1st kernel.
> Is this on kvm or on a real hardware? Because for kvm I don't care. And
> don't say "theoretically".
>
It's from my understanding, I didn't get the explicit description from the intel SDM on this point.
If a broadcast SRAO comes on real hardware, will MSR_IA32_MCG_STATUS of each cpu have MCG_STATUS_RIPV bit set?
Regards,
Xunlei
