Messages in this thread Patch in this message | | | From | Michael Ellerman <> | Subject | Re: powerpc KVM build break in linux-next (was Re: [PATCH tip/core/rcu 40/40] srcu: Parallelize callback handling) | Date | Fri, 21 Apr 2017 11:42:01 +1000 |
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"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>
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
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