From: Scott Wood <scottwood@freescale.com>
To: Alexander Graf <agraf@suse.de>
Cc: <kvm-ppc@vger.kernel.org>, <kvm@vger.kernel.org>
Subject: Re: [PATCH 1/3] KVM: PPC: e500: Call kvmppc_mmu_map for initial mapping
Date: Thu, 17 Jan 2013 18:47:15 -0600 [thread overview]
Message-ID: <1358470035.13978.22@snotra> (raw)
In-Reply-To: <F75E090F-2AE5-483E-BCDE-E9FAED2415ED@suse.de> (from agraf@suse.de on Thu Jan 17 18:20:03 2013)
On 01/17/2013 06:20:03 PM, Alexander Graf wrote:
>
> On 18.01.2013, at 01:11, Scott Wood wrote:
>
> > On 01/17/2013 04:50:39 PM, Alexander Graf wrote:
> >> @@ -1024,9 +1001,11 @@ void kvmppc_mmu_map(struct kvm_vcpu *vcpu,
> u64 eaddr, gpa_t gpaddr,
> >> {
> >> struct kvmppc_vcpu_e500 *vcpu_e500 = to_e500(vcpu);
> >> struct tlbe_priv *priv;
> >> - struct kvm_book3e_206_tlb_entry *gtlbe, stlbe;
> >> + struct kvm_book3e_206_tlb_entry *gtlbe, stlbe = {};
> >
> > Is there a code path in which stlbe gets used but not fully filled
> in
> > without this?
>
> I am hoping not, but when I wrote this patch gcc suddenly jumped at
> me claiming that the whole struct can get used uninitialized:
>
> arch/powerpc/kvm/e500_mmu_host.c: In function ‘kvmppc_mmu_map’:
> arch/powerpc/kvm/e500_mmu_host.c:533: error: ‘stlbe.mas1’ may be used
> uninitialized in this function
> arch/powerpc/kvm/e500_mmu_host.c:533: error: ‘stlbe.mas2’ may be used
> uninitialized in this function
> arch/powerpc/kvm/e500_mmu_host.c:533: error: ‘stlbe.mas7_3’ may be
> used uninitialized in this function
> arch/powerpc/kvm/e500_mmu_host.c:533: error: ‘stlbe.mas8’ may be used
> uninitialized in this function
>
> If you have any idea where this could come from, please let me know
> :).
I can't reproduce with either GCC 4.5.1 or GCC 4.7.2. Maybe from a
non-final version of the patch? It would be nice to not have this, and
have GCC be able to detect if we're actually missing something rather
than have it get zeroed.
BTW, it's "stlbe = {}" in this patch but after the file split, somehow
come out as "stlbe = { }". Was that patch supposed to be just a simple
cut and paste of part of the file?
-Scott
next prev parent reply other threads:[~2013-01-18 0:47 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-17 22:50 [PATCH 0/3] KVM: PPC: e500: Shadow TLB Improvements Alexander Graf
2013-01-17 22:50 ` [PATCH 1/3] KVM: PPC: e500: Call kvmppc_mmu_map for initial mapping Alexander Graf
2013-01-18 0:11 ` Scott Wood
2013-01-18 0:20 ` Alexander Graf
2013-01-18 0:29 ` Alexander Graf
2013-01-18 0:35 ` Scott Wood
2013-01-18 0:47 ` Scott Wood [this message]
2013-01-18 0:49 ` Alexander Graf
2013-01-18 1:16 ` Alexander Graf
2013-01-17 22:50 ` [PATCH 2/3] KVM: PPC: E500: Split host and guest MMU parts Alexander Graf
2013-01-17 22:50 ` [PATCH 3/3] KVM: PPC: e500: Implement TLB1-in-TLB0 mapping Alexander Graf
2013-01-18 0:31 ` Scott Wood
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