Re: [PATCH] x86/hyperv: Properly suspend/resume reenlightenment notifications

From: Wei Liu
Date: Wed May 13 2020 - 11:02:02 EST


On Tue, May 12, 2020 at 06:01:53PM +0200, Vitaly Kuznetsov wrote:
> Errors during hibernation with reenlightenment notifications enabled were
> reported:
>
> [ 51.730435] PM: hibernation entry
> [ 51.737435] PM: Syncing filesystems ...
> ...
> [ 54.102216] Disabling non-boot CPUs ...
> [ 54.106633] smpboot: CPU 1 is now offline
> [ 54.110006] unchecked MSR access error: WRMSR to 0x40000106 (tried to
> write 0x47c72780000100ee) at rIP: 0xffffffff90062f24
> native_write_msr+0x4/0x20)
> [ 54.110006] Call Trace:
> [ 54.110006] hv_cpu_die+0xd9/0xf0
> ...
>
> Normally, hv_cpu_die() just reassigns reenlightenment notifications to some
> other CPU when the CPU receiving them goes offline. Upon hibernation, there
> is no other CPU which is still online so cpumask_any_but(cpu_online_mask)
> returns >= nr_cpu_ids and using it as hv_vp_index index is incorrect.
> Disable the feature when cpumask_any_but() fails.
>
> Also, as we now disable reenlightenment notifications upon hibernation we
> need to restore them on resume. Check if hv_reenlightenment_cb was
> previously set and restore from hv_resume().
>
> Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>

Applied to hyperv-fixes.

Thank you all.

Wei.