Re: [PATCH v3 04/17] perf: x86/ds: Handle guest PEBS overflow PMI and inject it to guest

Peter Zijlstra
2021-01-26T05:17:00Z

On Mon, Jan 25, 2021 at 04:26:22PM +0800, Like Xu wrote:

> In the host and guest PEBS both enabled case,
> we'll get a crazy dmesg *bombing* about spurious PMI warning
> if we pass the host PEBS PMI "harmlessly" to the guest:
>
> [11261.502536] Uhhuh. NMI received for unknown reason 2c on CPU 36.
> [11261.502539] Do you have a strange power saving mode enabled?
> [11261.502541] Dazed and confused, but trying to continue

How? AFAICT handle_pmi_common() will increment handled when
GLOBAL_STATUS_BUFFER_OVF_BIT is set, irrespective of DS containing
data.