On 2012-04-03 13:06, Gilles Chanteperdrix wrote: > On 04/03/2012 09:59 AM, Jan Kiszka wrote: >> On 2012-04-03 09:54, Gilles Chanteperdrix wrote: >>> On 04/02/2012 11:58 PM, Jan Kiszka wrote: >>>> On 2012-04-02 23:55, Gilles Chanteperdrix wrote: >>>>> On 04/02/2012 10:59 PM, Jan Kiszka wrote: >>>>>> On 2012-04-02 22:56, Jan Kiszka wrote: >>>>>>>> No luck, I am using qemu 0.12.5, there is no -global option documented, >>>>>>> >>>>>>> Err, that's prehistoric. Use stable 1.0.x at least to receive proper >>>>>>> HPET support. >>>>>> >>>>>> Oh, and there is one further pitfall: You need to provide >>>>>> -no-kvm-irqchip to use the HPET with MSI support because qemu-kvm does >>>>>> not forward those MSIs to the kernel irqchip model. I'm sitting on >>>>>> patches... >>>>> >>>>> Yes, I needed that. It works now, except that I could not find how to >>>>> use an NFS root filesystem. But with an ext3 file-backed filesystem, I >>>>> could get that: >>>> >>>> If your NFS server runs on the host and you use userspace networking >>>> (default without additional parameters), the guest should be able to >>>> reach the server under 10.0.2.2 and use an IP like 10.0.2.15 (or dhcp). >>>> However, I recently failed to get this working as well but didn't dig >>>> deeper. >>> >>> Well, with -net user, I do not get any network interface on the >>> simulated kernel. Maybe there a special network driver to enable in the >>> kernel? The documentation does not say which network card is simulated, >>> and I do not see any with lspci. >> >> qemu-kvm emulates a rtl8139 by default. But, by just specifying -net >> user, you disable any network adapter. Just leave it out, -net user -net >> nic,model=rtl8139 is default. > > How is -net user supposed to work if there is no emulated nic on the > board. I tried -net nic first, but it did not work either, it seems to > use vlans, but I do not have vlans configured on my host nor any desire > to configure them. Is there not a way to simply share the host network > interface with the guest, the way virtualbox does it?
QEMU vlans have nothing to do with vlan frames on the wire. Just leave out any -net command line switch and you will get a 8139 attached to a userspace networking stack out of the box. > >> >>> >>> Something else, is it possible to run kvm using SCHED_FIFO policy? I >>> tried that and I almost got a lockup, was probably saved by throttling. >> >> Yes, but not without some patches and a lot of tuning on both guest and >> host side. A standard Linux kernel touches too many device models that >> will take a long time to make RT compatible. A simple access to a >> virtual graphic adapter will be like accessing a screwed up physical GPU >> with horrible latency. > > Yes, ok, but my main interest was the timer interrupt. Besides this does > not explain why I get a lockup. E.g. because the guest may spin in its VCPU thread waiting for events that the IO thread of QEMU cannot deliver as it gets no CPU time. Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux _______________________________________________ Adeos-main mailing list Adeos-main@gna.org https://mail.gna.org/listinfo/adeos-main
