From: "Paul E. McKenney" <paulmck@linux•vnet.ibm.com>
To: Michael Ellerman <michaele@au1•ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat•com>,
tglx@linutronix•de, kvm@vger•kernel.org, oleg@redhat•com,
peterz@infradead•org, fweisbec@gmail•com, bobby.prani@gmail•com,
jiangshanlai@gmail•com, linux-kernel@vger•kernel.org,
kvm-ppc@vger•kernel.org, josh@joshtriplett•org,
dhowells@redhat•com, edumazet@google•com,
"paulus@samba•org" <paulus@samba•org>,
rostedt@goodmis•org, dipankar@in•ibm.com,
mathieu.desnoyers@efficios•com, akpm@linux-foundation•org,
"linuxppc-dev@lists•ozlabs.org" <linuxppc-dev@lists•ozlabs.org>,
mingo@kernel•org
Subject: Re: powerpc KVM build break in linux-next (was Re: [PATCH tip/core/rcu 40/40] srcu: Parallelize callback handling)
Date: Thu, 20 Apr 2017 21:17:54 -0700 [thread overview]
Message-ID: <20170421041754.GV3956@linux.vnet.ibm.com> (raw)
In-Reply-To: <87zifatu3a.fsf@concordia.ellerman.id.au>
On Fri, Apr 21, 2017 at 11:42:01AM +1000, Michael Ellerman wrote:
> "Paul E. McKenney" <paulmck@linux•vnet.ibm.com> writes:
> > On Thu, Apr 20, 2017 at 05:28:32PM +0200, Paolo Bonzini wrote:
> >> On 20/04/2017 05:40, Michael Ellerman wrote:
> >> > "Paul E. McKenney" <paulmck@linux•vnet.ibm.com> writes:
> >> >
> >> > This change seems to have had the non-obvious effect of breaking the
> >> > powerpc KVM build.
> ...
> >>
> >> Michael, if you want to move the two srcu structs at the end of struct
> >> kvm, that would be fine by me. Please send a patch yourself so you can
> >> test it on PPC. Thanks,
> >
> > On the off-chance that it is at all helpful, I have added the commit
> > shown below to -rcu.
>
> As shown below :)
>
> > If it helps, I am happy to push this, but am just as happy to drop it
> > in favor of some other fix. If at all possible, I would like to get
> > this into the upcoming merge window.
>
> Thanks, this looks perfect to me, and if you're happy to put it on top
> of your tree that would limit the breakage to a smaller history window,
> so that would be ideal.
>
> Tested-by: Michael Ellerman <mpe@ellerman•id.au>
Thank you, Michael!
Paolo, does this look good to you? My upstream maintainer will be much
more likely to take this with your ack. ;-)
Thanx, Paul
> cheers
>
>
> >From a19a6617e2817e485ccc2f7cc5a97bd7ff769b87 Mon Sep 17 00:00:00 2001
> From: "Paul E. McKenney" <paulmck@linux•vnet.ibm.com>
> Date: Thu, 20 Apr 2017 17:30:06 -0700
> Subject: kvm: Move srcu_struct fields to end of struct kvm
>
> Parallelizing SRCU callback handling increased the size of srcu_struct,
> which moved the kvm_arch field within the kvm struct out of reach of
> powerpc's current assembly code, resulting in the following sort of
> build error:
>
> arch/powerpc/kvm/book3s_hv_rmhandlers.S:617: Error: operand out of range (0x000000000000b328 is not between 0xffffffffffff8000 and 0x0000000000007fff)
>
> This commit moves the srcu_struct fields in the kvm structure to follow
> the kvm_arch field, which again allows powerpc's assembly code to
> reach it.
>
> Reported-by: Stephen Rothwell <sfr@canb•auug.org.au>
> Reported-by: Michael Ellerman <michaele@au1•ibm.com>
> Reported-by: kbuild test robot <fengguang.wu@intel•com>
> Suggested-by: Paolo Bonzini <pbonzini@redhat•com>
> Signed-off-by: Paul E. McKenney <paulmck@linux•vnet.ibm.com>
> ---
> include/linux/kvm_host.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index 2c14ad9..96c8e29 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -375,8 +375,6 @@ struct kvm {
> struct mutex slots_lock;
> struct mm_struct *mm; /* userspace tied to this vm */
> struct kvm_memslots *memslots[KVM_ADDRESS_SPACE_NUM];
> - struct srcu_struct srcu;
> - struct srcu_struct irq_srcu;
> struct kvm_vcpu *vcpus[KVM_MAX_VCPUS];
>
> /*
> @@ -429,6 +427,8 @@ struct kvm {
> struct list_head devices;
> struct dentry *debugfs_dentry;
> struct kvm_stat_data **debugfs_stat_data;
> + struct srcu_struct srcu;
> + struct srcu_struct irq_srcu;
> };
>
> #define kvm_err(fmt, ...) \
> --
> cgit v1.1
next prev parent reply other threads:[~2017-04-21 4:18 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20170412174003.GA23207@linux.vnet.ibm.com>
2017-04-12 17:39 ` [PATCH tip/core/rcu 02/40] rcu: Make arch select smp_mb__after_unlock_lock() strength Paul E. McKenney
2017-04-13 9:21 ` Peter Zijlstra
2017-04-13 16:17 ` Paul E. McKenney
2017-04-13 9:24 ` Peter Zijlstra
2017-04-13 16:26 ` Paul E. McKenney
2017-04-13 16:37 ` Peter Zijlstra
2017-04-13 17:03 ` Paul E. McKenney
2017-04-19 13:38 ` Michael Ellerman
2017-04-19 15:09 ` Paul E. McKenney
[not found] ` <1492018825-25634-40-git-send-email-paulmck@linux.vnet.ibm.com>
2017-04-20 3:40 ` powerpc KVM build break in linux-next (was Re: [PATCH tip/core/rcu 40/40] srcu: Parallelize callback handling) Michael Ellerman
2017-04-20 14:19 ` Paul E. McKenney
2017-04-20 15:28 ` Paolo Bonzini
2017-04-21 0:38 ` Paul E. McKenney
2017-04-21 1:42 ` Michael Ellerman
2017-04-21 4:17 ` Paul E. McKenney [this message]
2017-04-21 7:27 ` Paolo Bonzini
2017-04-21 12:51 ` Paul E. McKenney
2017-04-22 6:09 ` Michael Ellerman
2017-04-21 2:13 ` Michael Ellerman
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