RE: [PATCH 0/3] Drivers: hv: add kexec support

[KY Srinivasan]

> -----Original Message-----
> From: Vitaly Kuznetsov [mailto:vkuznets@xxxxxxxxxx]
> Sent: Wednesday, May 20, 2015 9:46 AM
> To: devel@xxxxxxxxxxxxxxxxxxxxxx
> Cc: KY Srinivasan; Haiyang Zhang; linux-kernel@xxxxxxxxxxxxxxx; Dexuan Cui;
> Ingo Molnar; H. Peter Anvin; Thomas Gleixner; x86@xxxxxxxxxx
> Subject: [PATCH 0/3] Drivers: hv: add kexec support
> 
> To make general-purpose kexec (not just kdump) possible for Hyper-V
> guests
> we need to perform some additional cleanup before starting new kernel
> (see
> [PATCH 2/3] for the detailed description).
> 
> Know limitations: kexec with balloned out memory is not possible as the
> newly loaded kernel doesn't know about this memory and there is no way to
> ask the host to bring all the memory back on cleanup (or at least I'm not
> aware of such a way). Kexec with hotplugged memory leads to reboot (not
> exactly sure why).
> 
> This series is supposed to be applied on top of K.Y.'s "[PATCH V2 0/5]
> Drivers: hv: vmbus: Cleanup the vmbus unload path"

I was currently working on this exact issue. After I checked in the clockevents device based on the
Hyper-V timers, kexec has been broken since the hypervisor state with regards to the synthetic
interrupt controller is not correctly cleaned up. Thank you! Greg, will you be able to take these patches 
through your tree as well.

Regards,

K. Y
> 
> Vitaly Kuznetsov (3):
>   Drivers: hv: vmbus: remove hv_synic_free_cpu() call from
>     hv_synic_cleanup()
>   Drivers: hv: vmbus: add special kexec handler
>   Drivers: hv: don't do hypercalls when hypercall_page is NULL
> 
>  arch/x86/include/asm/mshyperv.h |  2 ++
>  arch/x86/kernel/cpu/mshyperv.c  | 30
> ++++++++++++++++++++++++++++++
>  drivers/hv/hv.c                 | 15 ++++++++-------
>  drivers/hv/vmbus_drv.c          | 15 +++++++++++++++
>  4 files changed, 55 insertions(+), 7 deletions(-)
> 
> --
> 1.9.3

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