From mboxrd@z Thu Jan  1 00:00:00 1970
From: Paul Mackerras <paulus@samba.org>
Date: Fri, 26 Apr 2013 23:52:47 +0000
Subject: Re: [PATCH v5 0/8] In-kernel XICS interrupt controller emulation
Message-Id: <20130426235247.GB5743@iris.ozlabs.ibm.com>
List-Id: <kvm-ppc.vger.kernel.org>
References: <20130418062926.GA25033@drongo>
 <369C14EF-DE69-454C-A2A3-E1CC8FBD3258@suse.de>
 <1366996413.26749.2@snotra>
In-Reply-To: <1366996413.26749.2@snotra>
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
To: Scott Wood <scottwood@freescale.com>
Cc: Alexander Graf <agraf@suse.de>, kvm@vger.kernel.org, kvm-ppc@vger.kernel.org

On Fri, Apr 26, 2013 at 12:13:33PM -0500, Scott Wood wrote:

> Also please note that we no longer hold kvm->lock during device
> creation, so your EEXIST check looks racy.

Huh?  Patch 2/8 adds this code:

+       mutex_lock(&kvm->lock);
+       if (kvm->arch.xics)
+               ret = -EEXIST;
+       else
+               kvm->arch.xics = xics;
+       mutex_unlock(&kvm->lock);

How is that racy?

Paul.