Re: [PATCH 1/2] KVM: MMU: fix SMAP virtualization

From: Andrew Morton <akpm@linux-foundation.org>
To: Davidlohr Bueso <dave@stgolabs.net>
Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Edward Cree <ecree@solarflare.com>, Bandan Das <bsd@redhat.com>,
	gleb@kernel.org, mtosatti@redhat.com, kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] KVM: MMU: fix SMAP virtualization
Date: Wed, 10 Jun 2015 11:08:49 -0700	[thread overview]
Message-ID: <20150610110849.c37b91940bcda177c93d09ff@linux-foundation.org> (raw)
In-Reply-To: <1433959366.3165.87.camel@stgolabs.net>

On Wed, 10 Jun 2015 11:02:46 -0700 Davidlohr Bueso <dave@stgolabs.net> wrote:

> On Wed, 2015-05-27 at 10:53 +0800, Xiao Guangrong wrote:
> > 
> > On 05/26/2015 10:48 PM, Paolo Bonzini wrote:
> > >
> > >
> > > On 26/05/2015 16:45, Edward Cree wrote:
> > >>>> This breaks older compilers that can't initialize anon structures.
> > >>>>
> > >>>> How old ? Even gcc 3.1 says you can use unnamed struct/union fields and
> > >>>> 3.2 is the minimum version required to compile the kernel as mentioned
> > >>>> in the README.
> > >>>>
> > >>>> We could simply just name the structure, but I doubt this is the
> > >>>> only place in the kernel code where it's being used this way :)
> > >> This appears to be GCC bug #10676, see <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=10676>
> > >> Says it was fixed in 4.6, but I believe the kernel supports GCCs much older
> > >> than that (back to 3.2).  I personally hit it on 4.4.7, the version shipped
> > >> with RHEL6.6.
> > >
> > > Yes, it will be fixed soon(ish).  Probably before you can get rid of the
> > > obnoxious disclaimer... :)
> > 
> > It has been fixed by Andrew:
> > 
> > From: Andrew Morton <akpm@linux-foundation.org>
> > Subject: arch/x86/kvm/mmu.c: work around gcc-4.4.4 bug
> 
> Folks, this fix is missing in both -tip and Linus' (4.1-rc7) tree. At
> least I'm running into it.

hm, yes, it's in linux-next so I dropped my copy.

I'll send it in to Linus today.