Hello all, I will do research experiment using hypervisor. But I have not decided the platform; both XEN and KVM work for me(my work is about MMU, specifically shadow page tables). Though I prefer XEN, it seems XEN development and debugging are not easy. For example, every time you add some code in hypervisor, you have to restart computer. I appreciate your suggestion. Thanks Liu, John _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
On 24/06/11 21:56, Liu John wrote:> Hello all, > > I will do research experiment using hypervisor. But I have not decided > the platform; both XEN and KVM work for me(my work is about MMU, > specifically shadow page tables). Though I prefer XEN, it seems XEN > development and debugging are not easy. For example, every time you > add some code in hypervisor, you have to restart computer. > > I appreciate your suggestion. > > > Thanks > Liu, JohnI am curious to know under what circumstances you think it is, or should be possible to make hypervisor code changes without rebooting? -- Andrew Cooper - Dom0 Kernel Engineer, Citrix XenServer T: +44 (0)1223 225 900, http://www.citrix.com _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
At 16:56 -0400 on 24 Jun (1308934602), Liu John wrote:> I will do research experiment using hypervisor. But I have not decided the > platform; both XEN and KVM work for me(my work is about MMU, specifically > shadow page tables). Though I prefer XEN, it seems XEN development and > debugging are not easy. For example, every time you add some code in > hypervisor, you have to restart computer.That''s true. However I usually find that when I make a mistake in hypervisor code the computer needs to be rebooted anyway. :) AIUI Xen can run under Qemu so the reboot time is not that long. Tim. -- Tim Deegan <Tim.Deegan@citrix.com> Principal Software Engineer, Xen Platform Team Citrix Systems UK Ltd. (Company #02937203, SL9 0BG) _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
On Mon, Jun 27, 2011 at 8:50 AM, Andrew Cooper <andrew.cooper3@citrix.com> wrote:> I am curious to know under what circumstances you think it is, or should be > possible to make hypervisor code changes without rebooting?Perhaps the following works in KVM? $ make kvm.ko $ sudo rmmod kvm $ sudo insmod kvm.ko If it''s stuff related only to the interface seen by VMs, and not to the interaction w/ the hardware, it''s probably pretty convenient. :-) -George _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
> > At 16:56 -0400 on 24 Jun (1308934602), Liu John wrote: > > I will do research experiment using hypervisor. But I have notdecided the> > platform; both XEN and KVM work for me(my work is about MMU,specifically> > shadow page tables). Though I prefer XEN, it seems XEN developmentand> > debugging are not easy. For example, every time you add some code in > > hypervisor, you have to restart computer. > > That''s true. However I usually find that when I make a mistake in > hypervisor code the computer needs to be rebooted anyway. :) > AIUI Xen can run under Qemu so the reboot time is not that long. >Just out of curiosity, can xen be run inside xen yet? And does it make debugging any easier? James _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
At 20:25 +1000 on 27 Jun (1309206300), James Harper wrote:> > > > At 16:56 -0400 on 24 Jun (1308934602), Liu John wrote: > > > I will do research experiment using hypervisor. But I have not > decided the > > > platform; both XEN and KVM work for me(my work is about MMU, > specifically > > > shadow page tables). Though I prefer XEN, it seems XEN development > and > > > debugging are not easy. For example, every time you add some code in > > > hypervisor, you have to restart computer. > > > > That''s true. However I usually find that when I make a mistake in > > hypervisor code the computer needs to be rebooted anyway. :) > > AIUI Xen can run under Qemu so the reboot time is not that long. > > > > Just out of curiosity, can xen be run inside xen yet? And does it make > debugging any easier?It can, as a HVM guest, (although I''ve been having trouble booting latest xen-unstable under itself; running Xen 4.0 under latest unstable seems to work). We''ve just had support added for running HVM guests inside nested Xen too. I don''t use it since I''m often working on hardware-specific or performance-related issues, neither of which debugs very well in a VM. For general development I keep a tight hold of one or two test-boxes with fast BIOS POST times. :) Tim. -- Tim Deegan <Tim.Deegan@citrix.com> Principal Software Engineer, Xen Platform Team Citrix Systems UK Ltd. (Company #02937203, SL9 0BG) _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
On Mon, Jun 27, 2011 at 4:46 PM, Tim Deegan <Tim.Deegan@citrix.com> wrote:> At 16:56 -0400 on 24 Jun (1308934602), Liu John wrote: >> I will do research experiment using hypervisor. But I have not decided the >> platform; both XEN and KVM work for me(my work is about MMU, specifically >> shadow page tables). Though I prefer XEN, it seems XEN development and >> debugging are not easy. For example, every time you add some code in >> hypervisor, you have to restart computer. > > That''s true. However I usually find that when I make a mistake in > hypervisor code the computer needs to be rebooted anyway. :) > AIUI Xen can run under Qemu so the reboot time is not that long. >Just out of my curiosity. Does Xen inside QEMU supports HVM guest? Wei. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
At 18:30 +0800 on 27 Jun (1309199414), Wei Liu wrote:> On Mon, Jun 27, 2011 at 4:46 PM, Tim Deegan <Tim.Deegan@citrix.com> wrote: > > At 16:56 -0400 on 24 Jun (1308934602), Liu John wrote: > >> I will do research experiment using hypervisor. But I have not decided the > >> platform; both XEN and KVM work for me(my work is about MMU, specifically > >> shadow page tables). Though I prefer XEN, it seems XEN development and > >> debugging are not easy. For example, every time you add some code in > >> hypervisor, you have to restart computer. > > > > That''s true. However I usually find that when I make a mistake in > > hypervisor code the computer needs to be rebooted anyway. :) > > AIUI Xen can run under Qemu so the reboot time is not that long. > > > > Just out of my curiosity. > > Does Xen inside QEMU supports HVM guest?I haven''t tried it. ISTR seeing patches for SVM support, at least, on qemu-devel a while back. So: maybe. :) Tim. -- Tim Deegan <Tim.Deegan@citrix.com> Principal Software Engineer, Xen Platform Team Citrix Systems UK Ltd. (Company #02937203, SL9 0BG) _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
On 06/27/2011 12:40 PM, Tim Deegan wrote:> At 18:30 +0800 on 27 Jun (1309199414), Wei Liu wrote: >> On Mon, Jun 27, 2011 at 4:46 PM, Tim Deegan<Tim.Deegan@citrix.com> wrote: >>> At 16:56 -0400 on 24 Jun (1308934602), Liu John wrote: >>>> I will do research experiment using hypervisor. But I have not decided the >>>> platform; both XEN and KVM work for me(my work is about MMU, specifically >>>> shadow page tables). Though I prefer XEN, it seems XEN development and >>>> debugging are not easy. For example, every time you add some code in >>>> hypervisor, you have to restart computer. >>> >>> That''s true. However I usually find that when I make a mistake in >>> hypervisor code the computer needs to be rebooted anyway. :) >>> AIUI Xen can run under Qemu so the reboot time is not that long. >>> >> >> Just out of my curiosity. >> >> Does Xen inside QEMU supports HVM guest? > > I haven''t tried it. ISTR seeing patches for SVM support, at least, on > qemu-devel a while back. So: maybe. :)As Tim said, QEMU implements some basic SVM emulation. But as this is quite old and nobody seemed to care, it is currently broken, AFAICT. At best it is not complete anyway and so probably unusable. But you can use the nested SVM support in KVM. Though the primary test vehicle is KVM on KVM ;-), we also tests Xen as a guest from time to time and it worked. So just use QEMU and say --enable-kvm or use qemu-kvm on an AMD machine and you can run Xen with HVM guests inside KVM. Regards, Andre. -- Andre Przywara AMD-Operating System Research Center (OSRC), Dresden, Germany _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel