Hello all, I am a novice at Xen and I have some questions about it and I will deeply appreciate the answer from any of you. 1. Can Xen be run on CPU that not support Virtualization Technology? Because I have a Pentium M CPU that does not support VT. 2. What is each variety of Xen kernel for? For example kernel-2.6-xen, kernel-2.6-xen0 and kernel-2.6-xenU. Which one should be used for the host OS? What are the differences between kernel-2.6-xen and kernel-2.6-xen0? 3. I have to build the customer Xen kernel to support some special device, can a newer version, such as 2.6.23.9 used in my system now, of linux kernel be used? Thanks! Best Regards, Zhiming Wu _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Hello all, I am a novice at Xen and I have some questions about it and I will deeply appreciate the answer from any of you. 1. Can Xen be run on CPU that not support Virtualization Technology? Because I have a Pentium M CPU that does not support VT. 2. What is each variety of Xen kernel for? For example kernel-2.6-xen, kernel-2.6-xen0 and kernel-2.6-xenU. Which one should be used for the host OS? What are the differences between kernel-2.6-xen and kernel-2.6-xen0? 3. I have to build the customer Xen kernel to support some special device, can a newer version, such as 2.6.23.9 used in my system now, of linux kernel be used? Thanks! Best Regards, Zhiming Wu _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Zhiming Wu wrote:> Hello all, > > I am a novice at Xen and I have some questions about it and I will > deeply appreciate the answer from any of you. > > 1. Can Xen be run on CPU that not support Virtualization Technology? > Because I have a Pentium M CPU that does not support VT. >There are two types of guests. para-virtualized and fully virtualized. Para-virtualized guests run a modified kernel which understands that it''s running in a virtualized environment, hence does not require emulation. Fully virtualized guests does the unmodified generic kernel and requires everything to be emulated and which requires supprt VT. Bottom line is that, to run para-virtualized guest VT is not needed, but for fully virtualized guests VT is required.> 2. What is each variety of Xen kernel for? For example kernel-2.6-xen, > kernel-2.6-xen0 and kernel-2.6-xenU. Which one should be used for the > host OS? What are the differences between kernel-2.6-xen and > kernel-2.6-xen0? >kernel-2.6-xen0 is the kernel which one need to run on the host kernel. kernel-2.6-xenU is the one modified kernel to run on guest os. Acutally you can run xen0 to boot your guests as well, but xenU kernel makes sure that it only includes the required drivers for the guest to run. New distributions like RHEL, Centos, Fedora and etc ship only one kernel which is kernel-xen and is used to run both host and guests.> 3. I have to build the customer Xen kernel to support some special > device, can a newer version, such as 2.6.23.9 used in my system now, of > linux kernel be used? >You have to either forward port xen to 2.6.23 or backward port your patch to the current version. Fedora does forward porting, but it''s still at 2.6.21. --Sadique> Thanks! > > Best Regards, > Zhiming Wu > > _______________________________________________ > Xen-users mailing list > Xen-users@lists.xensource.com > http://lists.xensource.com/xen-users > >_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Hello,> I am a novice at Xen and I have some questions about it and I will > deeply appreciate the answer from any of you.Sure.> 1. Can Xen be run on CPU that not support Virtualization Technology? > Because I have a Pentium M CPU that does not support VT.Yes but you''ll only be able to run Xen-aware (paravirtualised) guests. You can''t run unmodified OSes such as Windows.> 2. What is each variety of Xen kernel for? For example kernel-2.6-xen, > kernel-2.6-xen0 and kernel-2.6-xenU. Which one should be used for the > host OS? What are the differences between kernel-2.6-xen and > kernel-2.6-xen0?2.6-xen0 is a kernel with dom0 functionality compiled in, with a fair number of device drivers built into the kernel (if I recall correctly) and not that many other driver built as modules. 2.6-xen also has dom0 functionality compiled in and it compiles a much larger set of modules to ensure compatibility with more hardware. This is probably a good choice for a dom0 kernel, as it''ll support lots of devices by default. 2.6-xenU is a kernel that does not include dom0 functionality, so it can only run in an unprivileged domain. You can use this as the kernel in your guest VMs. You can use a dom0-aware kernel (2.6-xen or 2.6-xen0) in *any* domain, including an unprivileged domain. It is safe to use a dom0-aware kernel in an unprivileged domain, it won''t be able to do any harm. A 2.6-xenU build is just slightly smaller because it doesn''t include dom0 functionality - that''s the only difference.> 3. I have to build the customer Xen kernel to support some special > device, can a newer version, such as 2.6.23.9 used in my system now, of > linux kernel be used?Not really, no. You can''t build 2.6.23 from kernel.org to run as a dom0 *at all*, so you won''t be able to use that to get better device support. You can run 2.6.23 as a domU kernel, although the support is better tested and more complete if you use the XenLinux kernel from XenSource, at the moment. If you use a distro with good Xen support, such as Fedora or CentOS then it will include a distro-patched XenLinux kernel with extra driver support, etc. Fedora ports the Xen patches to work with newer versions of Linux. If you want a more stable, server OS, then you could try CentOS. CentOS 5 uses the 2.6.18 kernel but other drivers are backported to enhance its hardware support. There are other distros that do similar modifications, so you might find you have luck with one of those instead. Fedora and CentOS are just the ones I know most about ;-) Cheers, Mark -- Push Me Pull You - Distributed SCM tool (http://www.cl.cam.ac.uk/~maw48/pmpu/) _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
mark.williamson@cl.cam.ac.uk more or less, almost, wrote: [...] If you want a more stable server OS, try CentOS. CentOS 5 uses> the 2.6.18 kernel w/ drivers backported to enhance its hardware support.Mark, could you please share URLs for getting started with that? I''m sure many on-list will appreciate the extra information. Regards, -pbr _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Hi Sadique, Thank you very much for your detailed explanation. Best Regards, Zhiming Wu Sadique Puthen wrote:> Zhiming Wu wrote: >> Hello all, >> >> I am a novice at Xen and I have some questions about it and I will >> deeply appreciate the answer from any of you. >> >> 1. Can Xen be run on CPU that not support Virtualization Technology? >> Because I have a Pentium M CPU that does not support VT. >> > > There are two types of guests. para-virtualized and fully virtualized. > Para-virtualized guests run a modified kernel which understands that > it''s running in a virtualized environment, hence does not require > emulation. Fully virtualized guests does the unmodified generic kernel > and requires everything to be emulated and which requires supprt VT. > Bottom line is that, to run para-virtualized guest VT is not needed, but > for fully virtualized guests VT is required. > >> 2. What is each variety of Xen kernel for? For example kernel-2.6-xen, >> kernel-2.6-xen0 and kernel-2.6-xenU. Which one should be used for the >> host OS? What are the differences between kernel-2.6-xen and >> kernel-2.6-xen0? >> > > kernel-2.6-xen0 is the kernel which one need to run on the host kernel. > kernel-2.6-xenU is the one modified kernel to run on guest os. Acutally > you can run xen0 to boot your guests as well, but xenU kernel makes sure > that it only includes the required drivers for the guest to run. > > New distributions like RHEL, Centos, Fedora and etc ship only one kernel > which is kernel-xen and is used to run both host and guests. > >> 3. I have to build the customer Xen kernel to support some special >> device, can a newer version, such as 2.6.23.9 used in my system now, of >> linux kernel be used? >> > > You have to either forward port xen to 2.6.23 or backward port your > patch to the current version. Fedora does forward porting, but it''s > still at 2.6.21. > > --Sadique >> Thanks! >> >> Best Regards, >> Zhiming Wu >> >> _______________________________________________ >> Xen-users mailing list >> Xen-users@lists.xensource.com >> http://lists.xensource.com/xen-users >> >> > >_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Hi Mark, Thank you very much for you detailed explanation. Now I understand the situation and can decide what I should do. Best Regards, Zhiming Wu Mark Williamson wrote:> Hello, > > >> I am a novice at Xen and I have some questions about it and I will >> deeply appreciate the answer from any of you. >> > > Sure. > > >> 1. Can Xen be run on CPU that not support Virtualization Technology? >> Because I have a Pentium M CPU that does not support VT. >> > > Yes but you''ll only be able to run Xen-aware (paravirtualised) guests. You > can''t run unmodified OSes such as Windows. > > >> 2. What is each variety of Xen kernel for? For example kernel-2.6-xen, >> kernel-2.6-xen0 and kernel-2.6-xenU. Which one should be used for the >> host OS? What are the differences between kernel-2.6-xen and >> kernel-2.6-xen0? >> > > 2.6-xen0 is a kernel with dom0 functionality compiled in, with a fair number > of device drivers built into the kernel (if I recall correctly) and not that > many other driver built as modules. > > 2.6-xen also has dom0 functionality compiled in and it compiles a much larger > set of modules to ensure compatibility with more hardware. This is probably > a good choice for a dom0 kernel, as it''ll support lots of devices by default. > > 2.6-xenU is a kernel that does not include dom0 functionality, so it can only > run in an unprivileged domain. You can use this as the kernel in your guest > VMs. > > You can use a dom0-aware kernel (2.6-xen or 2.6-xen0) in *any* domain, > including an unprivileged domain. It is safe to use a dom0-aware kernel in > an unprivileged domain, it won''t be able to do any harm. > > A 2.6-xenU build is just slightly smaller because it doesn''t include dom0 > functionality - that''s the only difference. > > >> 3. I have to build the customer Xen kernel to support some special >> device, can a newer version, such as 2.6.23.9 used in my system now, of >> linux kernel be used? >> > > Not really, no. > > You can''t build 2.6.23 from kernel.org to run as a dom0 *at all*, so you won''t > be able to use that to get better device support. You can run 2.6.23 as a > domU kernel, although the support is better tested and more complete if you > use the XenLinux kernel from XenSource, at the moment. > > If you use a distro with good Xen support, such as Fedora or CentOS then it > will include a distro-patched XenLinux kernel with extra driver support, etc. > Fedora ports the Xen patches to work with newer versions of Linux. If you > want a more stable, server OS, then you could try CentOS. CentOS 5 uses the > 2.6.18 kernel but other drivers are backported to enhance its hardware > support. > > There are other distros that do similar modifications, so you might find you > have luck with one of those instead. Fedora and CentOS are just the ones I > know most about ;-) > > Cheers, > Mark > >_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
> [...] If you want a more stable server OS, try CentOS. CentOS 5 uses > > > the 2.6.18 kernel w/ drivers backported to enhance its hardware support. > > Mark, could you please share URLs for getting started with that? I''m > sure many on-list will appreciate the extra information.Apologies for the late response. Hmmm. Well, http://www.centos.org is the homepage of the CentOS project. Details of the CentOS Plus repository which contains a kernel with extra features enabled relative to the default CentOS configuration: http://wiki.centos.org/Repositories/CentOSPlus Note that the CentOS Plus kernel enables extra features in the build, but the vanilla CentOS kernel does (I believe) already contain some backported hardware support from newer kernel versions, so it may already contain stuff that the equivalent mainline kernel version does not. I don''t know if CentOS Plus backports even more stuff or just enables more compile options. I unfortunately can''t find a reference for the backporting of features to the vanilla CentOS / RHEL kernel codebase; I''ve found multiple references but nothing definitive. I believe it''s part of RedHat''s practices though this might be best confirmed by one of the RH developers. Cheers, Mark -- Push Me Pull You - Distributed SCM tool (http://www.cl.cam.ac.uk/~maw48/pmpu/) _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users