From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: memop struct packing, 32/64 bits Date: Mon, 23 Jan 2012 10:02:01 -0500 Message-ID: <20120123150201.GA11441@phenom.dumpdata.com> References: <20120122203714.GB30288@andromeda.dapyr.net> <4F1D355D020000780006E4E9@nat28.tlf.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <4F1D355D020000780006E4E9@nat28.tlf.novell.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Jan Beulich Cc: xen-devel@lists.xensource.com, Keir Fraser , ian.campbell@citrix.com, andres@lagarcavilla.org, ian.jackson@citrix.com, Konrad Rzeszutek Wilk List-Id: xen-devel@lists.xenproject.org On Mon, Jan 23, 2012 at 09:24:29AM +0000, Jan Beulich wrote: > >>> On 22.01.12 at 21:37, Konrad Rzeszutek Wilk wrote: > > So for the "Fun" of it I tried to see if the 'struct > > xen_processor_performance' has some 32/64-bit issues and was surprised > > to find they do. What I am more surprised to find is that nobody seems > > to have had any troubles with this as it seems to have been there since > > it was initially implemented. The major issue would have been with the > > 'shared_type', 'domain_info' and the pointer to the 'states' being at > > different offsets (So when running a 32-bit dom0 with a 64-bit > > hypervisor). > > Are you having an actual problem with the layout differences, or > did you just observe them? As Keir said, this is being dealt with > inside the hypervisor - the (Dom0) kernel doesn't need to care at > all (which was the primary requirement when the 32-on-64 > support got added). I just observed them when I was trying to use memcpy on the Linux<->Xen structs and saw some padding issues. The further I looked the more I saw of it and was wondering why nobody had tripped over it. But the compat layer that Keir pointed to me does fix the 32/64 bit issue I observed - so wheew, no bugs! Thanks! > > Jan > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xensource.com > http://lists.xensource.com/xen-devel