Re: [Qemu-devel] [PULL 26/44] spapr/xive: add KVM support

[Alexey Kardashevskiy]

On 04/06/2019 17:54, Cédric Le Goater wrote:
> On 04/06/2019 09:23, Alexey Kardashevskiy wrote:
>>
>>
>> On 29/05/2019 16:49, David Gibson wrote:
>>> From: Cédric Le Goater <address@hidden>
>>>
>>> This introduces a set of helpers when KVM is in use, which create the
>>> KVM XIVE device, initialize the interrupt sources at a KVM level and
>>> connect the interrupt presenters to the vCPU.
>>>
>>> They also handle the initialization of the TIMA and the source ESB
>>> memory regions of the controller. These have a different type under
>>> KVM. They are 'ram device' memory mappings, similarly to VFIO, exposed
>>> to the guest and the associated VMAs on the host are populated
>>> dynamically with the appropriate pages using a fault handler.
>>>
>>> Signed-off-by: Cédric Le Goater <address@hidden>
>>> Reviewed-by: David Gibson <address@hidden>
>>> Message-Id: <address@hidden>
>>> Signed-off-by: David Gibson <address@hidden>
>>
>>
>> This one breaks my setup - it boots up to:
>>
>>
>> ipr: IBM Power RAID SCSI Device Driver version: 2.6.4 (March 14, 2017)
>> __vio_register_driver: driver ibmvscsi registering
>> ibmvscsi 71000001: SRP_VERSION: 16.a
>> ibmvscsi 71000001: Maximum ID: 64 Maximum LUN: 32 Maximum Channel: 3
>> scsi host0: IBM POWER Virtual SCSI Adapter 1.5.9
>>
>>
>> and hangs. Here is the command line:
>>
>>
>> /home/aik/pbuild/qemu-aikrhel74alt-ppc64/ppc64-softmmu/qemu-system-ppc64 \
>> -nodefaults \
>> -chardev stdio,id=STDIO0,signal=off,mux=on \
>> -device spapr-vty,id=svty0,reg=0x71000110,chardev=STDIO0 \
>> -mon id=MON0,chardev=STDIO0,mode=readline -nographic -vga none \
>> -enable-kvm \
>> -device nec-usb-xhci,id=nec-usb-xhci0 -m 16G \
>> -netdev "user,id=USER0,hostfwd=tcp::2223-:22" \
>> -device "virtio-net-pci,id=vnet0,mac=C0:41:49:4b:00:00,netdev=USER0" \
>> img/u1804-64G-cuda10.1-418.67-swiotlb.qcow2 \
>> -machine pseries,cap-cfpc=broken,cap-htm=off,ic-mode=xive -snapshot \
>> -smp 1,threads=1 -bios ./slof.bin \
>> -L /home/aik/t/qemu-ppc64-bios/ \
>> -trace events=qemu_trace_events -d guest_errors \
>> -chardev socket,id=SOCKET0,server,nowait,path=qemu.mon.user2223 \
>> -mon chardev=SOCKET0,mode=control
> 
> At this level of patch 38afd772f802 ("spapr/xive: add KVM support"), I am
> surprised this is even starting. 
> 
> The test in spapr_irq_init_xive() : 
> 
>     /* KVM XIVE device not yet available */
>     if (kvm_enabled()) {
>         if (machine_kernel_irqchip_required(machine)) {
>             error_setg(errp, "kernel_irqchip requested. no KVM XIVE support");
>             return;
>         }
>     }
> 
> should fail. This is removed later in 0dc9f5f8496a ("spapr/xive: activate 
> KVM support")
> 
>> The host kernel is v5.2-rc2. The next patch - 0c575703e487 "spapr/xive:
>> add hcall support when under KVM" - fixes this though but the question
>> is now if xive emulation in qemu still works (how do I verify it?).
> 
> kernel_irqchip=off should activate the QEMU XIVE device.
> 
> Are you testing bisection ?


I was bisecting as I originally wanted to test the recent David's spapr
pci rework and things broke again, although differently, hence the noise
I made about xive.



-- 
Alexey