On 2016-04-26 09:57, Jan Kiszka wrote: > On 2016-04-26 09:34, Peter Xu wrote: >> On Mon, Apr 25, 2016 at 09:24:12AM +0200, Jan Kiszka wrote: >>> On 2016-04-25 09:18, Peter Xu wrote: >>>> On Mon, Apr 25, 2016 at 07:16:19AM +0200, Jan Kiszka wrote: >>>>> On 2016-04-19 10:38, Peter Xu wrote: >>>> >>>> [...] >>>> >>>>>> By default, IR is disabled to be better compatible with current >>>>>> QEMU. To enable IR, we can using the following command to boot a >>>>>> IR-supported VM with virtio-net device with vhost (still do not >>>>>> support kvm-ioapic, so we need to specify kernel-irqchip={split|off} >>>>>> here): >>>>>> >>>>>> $ qemu-system-x86_64 -M q35,iommu=on,intr=on,kernel-irqchip=split \ >>>>> >>>>> "intr" sounds a bit too much like "interrupt", not "interrupt >>>>> remapping". Why not use the kernel's form, "intremap"? >>>> >>>> Sure. It sounds nice to be aligned with the kernel one. Let me take >>>> it in v5. >>>> >>>>> >>>>>> -enable-kvm -m 1024 \ >>>>>> -netdev tap,id=net0,vhost=on \ >>>>>> -device virtio-net-pci,netdev=user.0 \ >>>>>> -monitor telnet::3333,server,nowait \ >>>>>> /var/lib/libvirt/images/vm1.qcow2 >>>>>> >>>>>> When guest boots, we can verify whether IR enabled by grepping the >>>>>> dmesg like: >>>>>> >>>>>> [root@localhost ~]# journalctl -k | grep "DMAR-IR" >>>>>> Feb 19 11:21:23 localhost.localdomain kernel: DMAR-IR: IOAPIC id 0 under >>>>>> DRHD base 0xfed90000 IOMMU 0 >>>>>> Feb 19 11:21:23 localhost.localdomain kernel: DMAR-IR: Enabled IRQ >>>>>> remapping in xapic mode >>>>>> >>>>>> Currently supported devices: >>>>>> >>>>>> - Emulated/Splitted irqchip >>>>>> - Generic PCI Devices >>>>>> - vhost devices >>>>>> - pass through device support? Not tested, but suppose it should work. >>>>> >>>>> I've tested this series against my Jailhouse setup, and it works pretty >>>>> well! Actually considering to move my test setup over this branch. >>>> >>>> This is really encouraging feedback! Btw, thanks for all kinds of >>>> help on this patchset. :-) >>>> >>>>> >>>>> However, split irqchip still has some issues: When I boot a q35 machine >>>>> with Linux, the e1000 network adapter only gets a single IRQ delivered. >>>>> Interestingly, other IOAPIC IRQs like the keyboard work all the time. I >>>>> didn't debug this in details yet. >>>> >>>> I reproduced this problem. It seems that it fails even with >>>> kernel-irqchip=off. Will try to dig it out. >>> >>> Very good. Hope it can be easily fixed. >> >> Hi, Jan, >> >> The above issue should be caused by EOI missing of level-triggered >> interrupts. Before that, I was always using edge-triggered >> interrupts for test, so didn't encounter this one. Would you please >> help try below patch? It can be applied directly onto the series, >> and should solve the issue (it works on my test vm, and I'll take it >> in v5 as well if it also works for you): >> > > Works here as well. I even made EIM working with some hack, though > Jailhouse spits out strange warnings, despite it works fine (x2apic > mode, split irqchip).
Corrections: the warnings are issued by qemu, not Jailhouse, e.g. qemu-system-x86_64: VT-d Failed to remap interrupt for gsi 22. I suspect that comes from the hand-over phase of Jailhouse, when it mutes all interrupts in the system while reconfiguring IR and IOAPIC. Please convert this error (in kvm_arch_fixup_msi_route) into a trace point. It shall not annoy the host. Also check if you have more of such guest-triggerable error messages. Jan