Hi, Keir, Per agreement on last xen summit, now xen/ia64 community is working on moving dom0 from current p==m model to p!=m model. First an easy way is chosen by Isaku that physmap is invisible to dom0 which is instead managed by Xen. After some investigation, we found that existing auto_translated_mode matches our model and then would like to know the status of this mode on xen/x86. 1. First a background question, what''s the major usage model for auto_translated_mode? 2. Is auto_translated_mode only used for domU? Seems this model can''t apply to modified DMA interface since mfn is required to manipulate physical devices. 3. Does anyone exercise this mode recently? Is this logic working or broken? We''d like to know which areas need to be enhanced if this translated mode can be applied to dom0. That would save people much time since virtual drivers together with grant table have been tuned to accommodate this mode. Then this translated mode may be made more generic. :-) Thanks, Kevin _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
> Hi, Keir, > Per agreement on last xen summit, now xen/ia64 > community is working on moving dom0 from current p==m model > to p!=m model. First an easy way is chosen by Isaku that > physmap is invisible to dom0 which is instead managed by Xen. > After some investigation, we found that existing > auto_translated_mode matches our model and then would like to > know the status of this mode on xen/x86. > > 1. First a background question, what''s the major usage model > for auto_translated_mode?Currently, the main usage model is to support guests that haven''t got fully paravirtualied mm systems. It''s also useful for a number of research projects, such as vm fork, determinsitic replay etc.> 2. Is auto_translated_mode only used for domU? Seems this > model can''t apply to modified DMA interface since mfn is > required to manipulate physical devices.It''s currently only used for domU''s, and needs to be extended to support lookup of mfn''s for DMA addresses, and to enable the backend drives to work.> 3. Does anyone exercise this mode recently? Is this logic > working or broken?Definitely working.> We''d like to know which areas need to be enhanced if > this translated mode can be applied to dom0. That would save > people much time since virtual drivers together with grant > table have been tuned to accommodate this mode. Then this > translated mode may be made more generic. :-)The first thing I would do is get physcial device access working from for a auto_translate guest. Ian _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
>From: Ian Pratt [mailto:m+Ian.Pratt@cl.cam.ac.uk] >Sent: 2006年3月28日 20:33 >> 1. First a background question, what''s the major usage model >> for auto_translated_mode? > >Currently, the main usage model is to support guests that haven''t got >fully paravirtualied mm systems. It''s also useful for a number of >research projects, such as vm fork, determinsitic replay etc.Thanks for clarification. Seems XENFEAT_supervisor_mode_kernel also serves for similar research purpose, right? :-)> >> 2. Is auto_translated_mode only used for domU? Seems this >> model can''t apply to modified DMA interface since mfn is >> required to manipulate physical devices. > >It''s currently only used for domU''s, and needs to be extended to support >lookup of mfn''s for DMA addresses, and to enable the backend drives to >work.OK, then that''s the areas xen/ia64 needs to solve since we want dom0 to run on top of this model.> >> 3. Does anyone exercise this mode recently? Is this logic >> working or broken? > >Definitely working.Great.> >> We''d like to know which areas need to be enhanced if >> this translated mode can be applied to dom0. That would save >> people much time since virtual drivers together with grant >> table have been tuned to accommodate this mode. Then this >> translated mode may be made more generic. :-) > >The first thing I would do is get physcial device access working from >for a auto_translate guest. > >IanYep. Thanks, Kevin _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
Ian Pratt wrote:>>After some investigation, we found that existing >>auto_translated_mode matches our model and then would like to >>know the status of this mode on xen/x86. >> >>1. First a background question, what''s the major usage model >>for auto_translated_mode? >> >> > >Currently, the main usage model is to support guests that haven''t got >fully paravirtualied mm systems. It''s also useful for a number of >research projects, such as vm fork, determinsitic replay etc. > > >A quick question: Can this be enabled on a per domU basis and how is this done correctly? The furthest I can track it is in tools/libxc/xc_linux_build.c shadow_mode_enabled = test_feature_bit(XENFEAT_auto_translated_physmap, required_features); one could of course for now hardcode shadow_mode_enabled to 1, but it sounds like there would be a config file option for this kind of thing. I can not seem to backtrack this any further. So my question is this: how do I enable translated shadow mode as cleanly as possible? Best Regards, Jesper Kristensen _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
>From: Jesper Kristensen >Sent: 2006年3月28日 22:02 >Ian Pratt wrote: > >>>After some investigation, we found that existing >>>auto_translated_mode matches our model and then would like to >>>know the status of this mode on xen/x86. >>> >>>1. First a background question, what''s the major usage model >>>for auto_translated_mode? >>> >>> >> >>Currently, the main usage model is to support guests that haven''t got >>fully paravirtualied mm systems. It''s also useful for a number of >>research projects, such as vm fork, determinsitic replay etc. >> >> >> >A quick question: Can this be enabled on a per domU basis and how is >this done correctly? The furthest I can track it is in >tools/libxc/xc_linux_build.c > > shadow_mode_enabled >test_feature_bit(XENFEAT_auto_translated_physmap, >required_features); > >one could of course for now hardcode shadow_mode_enabled to 1, but it >sounds like there would be a config file option for this kind of thing. >I can not seem to backtrack this any further. So my question is this: >how do I enable translated shadow mode as cleanly as possible? > >Best Regards, >Jesper KristensenYou can add a "features=" in your config file, which will be parsed and then passed to xc_linux_build. Thanks, Kevin _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
On Tue, 2006-03-28 at 16:01 +0200, Jesper Kristensen wrote:> So my question is this: how do I enable translated shadow mode as cleanly as possible?You can add "features = auto_translated_physmap" to the domU configuration file, this filters down to the test_feature_bit() call which you observed. xen-unstable changeset 9002 introduced all this. Ian. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
On 3/28/06, Jesper Kristensen <cableman@cs.aau.dk> wrote:> A quick question: Can this be enabled on a per domU basis and how is > this done correctly? The furthest I can track it is in > tools/libxc/xc_linux_build.c > > shadow_mode_enabled > test_feature_bit(XENFEAT_auto_translated_physmap, required_features); > > one could of course for now hardcode shadow_mode_enabled to 1, but it > sounds like there would be a config file option for this kind of thing. > I can not seem to backtrack this any further. So my question is this: > how do I enable translated shadow mode as cleanly as possible?You can either enable it by adding "FEATURES=!auto_translated_physmap" to the xen_guest section of your kernel image or you can enable it from the xm create command line or config file: features=auto_translated_physmap. christian _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel