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From: Avi Kivity <avi@redhat.com>
To: Scott Wood <scottwood@freescale.com>
Cc: Alexander Graf <agraf@suse.de>,
	kvm-ppc@vger.kernel.org, kvm list <kvm@vger.kernel.org>,
	Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: [PATCH 04/14] KVM: PPC: e500: MMU API
Date: Wed, 02 Nov 2011 12:33:34 +0200	[thread overview]
Message-ID: <4EB11C7E.6050703@redhat.com> (raw)
In-Reply-To: <4EB01B4B.8090209@freescale.com>

On 11/01/2011 06:16 PM, Scott Wood wrote:
> > 
> > sizeof(struct kvm_tlb_dirty) == 12 for 32-bit userspace, but ==  16 for
> > 64-bit userspace and the kernel.  ABI structures must have the same
> > alignment and size for 32/64 bit userspace, or they need compat handling.
>
> The size is 16 on 32-bit ppc -- the alignment of __u64 forces this.  It
> looks like this is different in the 32x86 ABI.

Right, __u64 alignment on i386 is 4.

> We can pad explicitly if you prefer.

No real need - unless it may be reused by another arch?  I think that's
unlikely.

> >> This API has been discussed extensively, and the code using it is
> >> already in mainline QEMU.  This aspect of it hasn't changed since the
> >> discussion back in February:
> >>
> >> http://www.spinics.net/lists/kvm/msg50102.html
> >>
> >> I'd prefer to avoid another round of major overhaul without a really
> >> good reason.
> > 
> > Me too, but I also prefer not to make ABI choices by inertia.  ABI is
> > practically the only thing I care about wrt non-x86 (other than
> > whitespace, of course).  Please involve me in the discussions earlier in
> > the future.
>
> You participated in that thread. :-)

Well, my memory isn't what it used to be, or at least what I seem to
remember it used to be.

> >>
> >> These are the assumptions needed to make such an interface well-defined.
> > 
> > Just remarking on the complexity, don't take it personally.
>
> :-)
>
> Just wasn't sure whether the implication was that it was too complex.
>

It is too complex, but that's entirely the fault of the hardware.  All
we can do is complain and enjoy the guaranteed job security.

-- 
error compiling committee.c: too many arguments to function


WARNING: multiple messages have this Message-ID (diff)
From: Avi Kivity <avi@redhat.com>
To: Scott Wood <scottwood@freescale.com>
Cc: Alexander Graf <agraf@suse.de>,
	kvm-ppc@vger.kernel.org, kvm list <kvm@vger.kernel.org>,
	Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: [PATCH 04/14] KVM: PPC: e500: MMU API
Date: Wed, 02 Nov 2011 10:33:34 +0000	[thread overview]
Message-ID: <4EB11C7E.6050703@redhat.com> (raw)
In-Reply-To: <4EB01B4B.8090209@freescale.com>

On 11/01/2011 06:16 PM, Scott Wood wrote:
> > 
> > sizeof(struct kvm_tlb_dirty) = 12 for 32-bit userspace, but =  16 for
> > 64-bit userspace and the kernel.  ABI structures must have the same
> > alignment and size for 32/64 bit userspace, or they need compat handling.
>
> The size is 16 on 32-bit ppc -- the alignment of __u64 forces this.  It
> looks like this is different in the 32x86 ABI.

Right, __u64 alignment on i386 is 4.

> We can pad explicitly if you prefer.

No real need - unless it may be reused by another arch?  I think that's
unlikely.

> >> This API has been discussed extensively, and the code using it is
> >> already in mainline QEMU.  This aspect of it hasn't changed since the
> >> discussion back in February:
> >>
> >> http://www.spinics.net/lists/kvm/msg50102.html
> >>
> >> I'd prefer to avoid another round of major overhaul without a really
> >> good reason.
> > 
> > Me too, but I also prefer not to make ABI choices by inertia.  ABI is
> > practically the only thing I care about wrt non-x86 (other than
> > whitespace, of course).  Please involve me in the discussions earlier in
> > the future.
>
> You participated in that thread. :-)

Well, my memory isn't what it used to be, or at least what I seem to
remember it used to be.

> >>
> >> These are the assumptions needed to make such an interface well-defined.
> > 
> > Just remarking on the complexity, don't take it personally.
>
> :-)
>
> Just wasn't sure whether the implication was that it was too complex.
>

It is too complex, but that's entirely the fault of the hardware.  All
we can do is complain and enjoy the guaranteed job security.

-- 
error compiling committee.c: too many arguments to function


  reply	other threads:[~2011-11-02 10:33 UTC|newest]

Thread overview: 82+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-10-31  7:53 [PULL 00/14] ppc patch queue 2011-10-31 Alexander Graf
2011-10-31  7:53 ` Alexander Graf
2011-10-31  7:53 ` [PATCH 01/14] KVM: PPC: e500: don't translate gfn to pfn with preemption disabled Alexander Graf
2011-10-31  7:53   ` Alexander Graf
2011-10-31 12:50   ` Avi Kivity
2011-10-31 12:50     ` [PATCH 01/14] KVM: PPC: e500: don't translate gfn to pfn with Avi Kivity
2011-10-31 18:52     ` [PATCH 01/14] KVM: PPC: e500: don't translate gfn to pfn with preemption disabled Scott Wood
2011-10-31 18:52       ` [PATCH 01/14] KVM: PPC: e500: don't translate gfn to pfn with Scott Wood
2011-11-01  9:00       ` [PATCH 01/14] KVM: PPC: e500: don't translate gfn to pfn with preemption disabled Avi Kivity
2011-11-01  9:00         ` [PATCH 01/14] KVM: PPC: e500: don't translate gfn to pfn with Avi Kivity
2011-10-31  7:53 ` [PATCH 02/14] KVM: PPC: e500: Eliminate preempt_disable in local_sid_destroy_all Alexander Graf
2011-10-31  7:53   ` Alexander Graf
2011-10-31  7:53 ` [PATCH 03/14] KVM: PPC: e500: clear up confusion between host and guest entries Alexander Graf
2011-10-31  7:53   ` Alexander Graf
2011-10-31  7:53 ` [PATCH 04/14] KVM: PPC: e500: MMU API Alexander Graf
2011-10-31  7:53   ` Alexander Graf
2011-10-31 13:24   ` Avi Kivity
2011-10-31 13:24     ` Avi Kivity
2011-10-31 20:12     ` Scott Wood
2011-10-31 20:12       ` Scott Wood
2011-11-01  8:58       ` Avi Kivity
2011-11-01  8:58         ` Avi Kivity
2011-11-01  9:55         ` Avi Kivity
2011-11-01  9:55           ` Avi Kivity
2011-11-01 16:16         ` Scott Wood
2011-11-01 16:16           ` Scott Wood
2011-11-02 10:33           ` Avi Kivity [this message]
2011-11-02 10:33             ` Avi Kivity
2011-11-10 14:20           ` Alexander Graf
2011-11-10 14:20             ` Alexander Graf
2011-11-10 14:16             ` Avi Kivity
2011-11-10 14:16               ` Avi Kivity
2011-10-31  7:53 ` [PATCH 05/14] KVM: PPC: e500: tlbsx: fix tlb0 esel Alexander Graf
2011-10-31  7:53   ` Alexander Graf
2011-10-31  7:53 ` [PATCH 06/14] KVM: PPC: e500: Don't hardcode PIR=0 Alexander Graf
2011-10-31  7:53   ` Alexander Graf
2011-10-31 13:27   ` Avi Kivity
2011-10-31 13:27     ` Avi Kivity
2011-10-31  7:53 ` [PATCH 07/14] KVM: PPC: Fix build failure with HV KVM and CBE Alexander Graf
2011-10-31  7:53   ` Alexander Graf
2011-10-31  7:53 ` [PATCH 08/14] Revert "KVM: PPC: Add support for explicit HIOR setting" Alexander Graf
2011-10-31  7:53   ` Alexander Graf
2011-10-31 13:30   ` Avi Kivity
2011-10-31 13:30     ` [PATCH 08/14] Revert "KVM: PPC: Add support for explicit HIOR Avi Kivity
2011-10-31 23:49     ` [PATCH 08/14] Revert "KVM: PPC: Add support for explicit HIOR setting" Alexander Graf
2011-10-31 23:49       ` Alexander Graf
2011-10-31  7:53 ` [PATCH 09/14] KVM: PPC: Add generic single register ioctls Alexander Graf
2011-10-31  7:53   ` Alexander Graf
2011-10-31 13:36   ` Avi Kivity
2011-10-31 13:36     ` Avi Kivity
2011-10-31 17:26     ` Jan Kiszka
2011-10-31 17:26       ` Jan Kiszka
2011-11-10 14:22     ` Alexander Graf
2011-11-10 14:22       ` Alexander Graf
2011-11-10 16:05   ` Marcelo Tosatti
2011-11-10 16:05     ` Marcelo Tosatti
2011-11-10 16:49     ` Alexander Graf
2011-11-10 16:49       ` Alexander Graf
2011-11-10 17:35       ` Marcelo Tosatti
2011-11-10 17:35         ` Marcelo Tosatti
2011-11-15 23:45         ` Alexander Graf
2011-11-15 23:45           ` Alexander Graf
2011-11-23 12:47           ` Marcelo Tosatti
2011-11-23 12:47             ` Marcelo Tosatti
2011-12-19 12:58             ` Alexander Graf
2011-12-19 12:58               ` Alexander Graf
2011-12-19 17:29               ` Marcelo Tosatti
2011-12-19 17:29                 ` Marcelo Tosatti
2011-10-31  7:53 ` [PATCH 10/14] KVM: PPC: Add support for explicit HIOR setting Alexander Graf
2011-10-31  7:53   ` Alexander Graf
2011-10-31  7:53 ` [PATCH 11/14] KVM: PPC: Whitespace fix for kvm.h Alexander Graf
2011-10-31  7:53   ` Alexander Graf
2011-10-31  7:53 ` [PATCH 12/14] KVM: Fix whitespace in kvm_para.h Alexander Graf
2011-10-31  7:53   ` Alexander Graf
2011-10-31  7:53 ` [PATCH 13/14] KVM: PPC: E500: Support hugetlbfs Alexander Graf
2011-10-31  7:53   ` Alexander Graf
2011-10-31 13:38   ` Avi Kivity
2011-10-31 13:38     ` Avi Kivity
2011-11-10 14:24     ` Alexander Graf
2011-11-10 14:24       ` Alexander Graf
2011-10-31  7:53 ` [PATCH 14/14] PPC: Fix race in mtmsr paravirt implementation Alexander Graf
2011-10-31  7:53   ` Alexander Graf

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