RE: [PATCH 1/1] X86/Hyper-V:: Fix the circular dependency in IPI enlightenment.

From: KY Srinivasan
Date: Thu Jul 05 2018 - 23:59:32 EST




> -----Original Message-----
> From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Sent: Thursday, July 5, 2018 3:46 PM
> To: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: KY Srinivasan <kys@xxxxxxxxxxxxx>; x86@xxxxxxxxxx;
> gregkh@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> devel@xxxxxxxxxxxxxxxxxxxxxx; olaf@xxxxxxxxx; apw@xxxxxxxxxxxxx;
> jasowang@xxxxxxxxxx; hpa@xxxxxxxxx; Stephen Hemminger
> <sthemmin@xxxxxxxxxxxxx>; Michael Kelley (EOSG)
> <Michael.H.Kelley@xxxxxxxxxxxxx>; vkuznets@xxxxxxxxxx
> Subject: Re: [PATCH 1/1] X86/Hyper-V:: Fix the circular dependency in IPI
> enlightenment.
>
> On Fri, 6 Jul 2018, Ingo Molnar wrote:
> > * KY Srinivasan <kys@xxxxxxxxxxxxx> wrote:
> > > I am confused. The label ipi_mask_done was introduced in this patch
> > > (the patch under question fixes a circular dependency in this patch):
> > >
> > > commit 68bb7bfb7985df2bd15c2dc975cb68b7a901488a
> > > Author: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
> > > Date: Wed May 16 14:53:31 2018 -0700
> > >
> > > X86/Hyper-V: Enable IPI enlightenments
> > >
> > > Hyper-V supports hypercalls to implement IPI; use them.
> > >
> > > Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
> > > Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> > > Reviewed-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
> > >
> > > This patch was committed by Thomas some weeks ago and is in linux-
> next.
> > > This patch is also in 4.18-rc3.
> >
> > And then that name was changed to a different label in:
> >
> > 4bd06060762b: x86/hyper-v: Use cheaper HVCALL_SEND_IPI hypercall
> when possible
> >
> > So maybe you were testing on an older kernel. Could you try the latest -
> tip?


>
> The problem is that the wreckage is in Linus tree and needs to be fixed
> there, i.e. via x86/urgent.
>
> Now we have the new bits queued in x86/hyperv already which collide. So
> we
> need to merge x86/urgent into x86/hyperv after applying the fix and mop up
> the merge wreckage in x86/hyperv.
>
> I'll have a look tomorrow morning unless you beat me to it.

I can rebase this patch against the latest tip and resend (tomorrow).

K. Y
>
> Thanks,
>
> tglx