RE: [PATCH v6][RESEND] x86/hyperv: Suspend/resume the hypercall page for hibernation

[Dexuan Cui]

> From: linux-hyperv-owner@xxxxxxxxxxxxxxx
> <linux-hyperv-owner@xxxxxxxxxxxxxxx> On Behalf Of Sasha Levin
> Sent: Wednesday, January 29, 2020 4:06 PM
> To: Dexuan Cui <decui@xxxxxxxxxxxxx>
> Cc: arnd@xxxxxxxx; bp@xxxxxxxxx; daniel.lezcano@xxxxxxxxxx; Haiyang Zhang
> <haiyangz@xxxxxxxxxxxxx>; hpa@xxxxxxxxx; KY Srinivasan
> <kys@xxxxxxxxxxxxx>; linux-hyperv@xxxxxxxxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx; mingo@xxxxxxxxxx; Stephen Hemminger
> <sthemmin@xxxxxxxxxxxxx>; tglx@xxxxxxxxxxxxx; x86@xxxxxxxxxx; Michael
> Kelley <mikelley@xxxxxxxxxxxxx>; Sasha Levin
> <Alexander.Levin@xxxxxxxxxxxxx>; vkuznets <vkuznets@xxxxxxxxxx>;
> linux-arch@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v6][RESEND] x86/hyperv: Suspend/resume the hypercall
> page for hibernation
> 
> On Sat, Jan 25, 2020 at 01:44:31AM +0000, Dexuan Cui wrote:
> >> From: Dexuan Cui <decui@xxxxxxxxxxxxx>
> >> Sent: Monday, January 6, 2020 2:43 PM
> >>
> >> This is needed for hibernation, e.g. when we resume the old kernel, we
> need
> >> to disable the "current" kernel's hypercall page and then resume the old
> >> kernel's.
> >>
> >> Signed-off-by: Dexuan Cui <decui@xxxxxxxxxxxxx>
> >> Reviewed-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
> >> ---
> >>
> >> This is a RESEND of https://lkml.org/lkml/2019/11/20/68
> >>
> >> Please review.
> >>
> >> If it looks good, can you please pick it up through the tip.git tree?
> >>
> >>  arch/x86/hyperv/hv_init.c | 48
> >> +++++++++++++++++++++++++++++++++++++++
> >>  1 file changed, 48 insertions(+)
> >
> >Hi, Vitaly and x86 maintainers,
> >Can you please take a look at this patch?
> 
> Ping?
> 
> This patch has been floating around in it's current form for the past 2
> months. I'll happily take Hyper-V patches under arch/x86/hyperv/ via the
> Hyper-V tree rather than tip if the x86 folks don't want to deal with
> them.
> 
> --
> Thanks,
> Sasha

This straightforward patch is the only pending patch for v5.6 for the
hibernation functionality of Linux VM on Hyper-V. It would be really great
if we could merge it for v5.6-rc1. The patch is safe in that it only runs when 
the VM hibernates, and the hibernation functionality of Linux VM on
Hyper-V never worked before. I'm pretty sure the patch can not cause any
merge conflict since nobody else tries to modify the file recently.

Thanks,
-- Dexuan