Re: kvm enable over cortex-a53?

[Marc Zyngier <marc.zyngier@arm.com>]

On 02/06/14 10:09, Lei Wen wrote:
> Hi,
> 
> I am current try to enable kvm over cortex-a53 over 3.10 kernel.
> After some patches backporting, I manage to get the /dev/kvm showed
> out, and build
> pass for the kernel.
> 
> However while I try to use the lkvm to launch the guest, some error shows up:
> 
>   # lkvm run -k nfs/Image -m 256 -c 1 --name guest-143
>   Warning: nfs/Image is not a bzImage. Trying to load it as a flat binary...
>   Info: Loaded kernel to 0x100080000 (18072024 bytes)
>   Info: Placing fdt at 0x10fe00000 - 0x10fffffff
>   Info: virtio-mmio.devices=0x200@0x10000:36
> 
>   Info: virtio-mmio.devices=0x200@0x10200:37
> 
>   Info: virtio-mmio.devices=0x200@0x10400:39
> 
> Emulate result 0
> KVM exit reason: 6 ("KVM_EXIT_MMIO")
> 
>  Registers:
>  PC:    0xffffffc000091a3c
>  PSTATE:    0x200002c5
>  SP_EL1:    0xffffffc0010ebcb0
>  LR:    0xffffffc000091a84
> 
> With further checking it seem that while it try to access the console
> driver whose
> base address is over 0xd4018000, but it failed to pass the checking by
> arm_addr_in_ioport_region and arm_addr_in_virtio_mmio_region, thus panic_kvm
> is invoked.

kvmtool tells you where the console lives (it is one of the virtio-mmio
devices that it prints out when it starts). The address you quote
(assuming that this is an IPA) doesn't seem to have anything to do with
anything kvmtool emulates. Pretty sure your kernel is trying to poke at
some area without parsing the device tree...

> My question is whether ARM_IOPORT_AREA/ARM_MMIO_AREA/
> ARM_AXI_AREA/ARM_MEMORY_AREA need to be reconfigured for different
> SOCs?

No. That's the whole point of a virtual machine.

> While I try to hack those MACRO into some value to let 0xd4018000 checking
> passed, but seems host kernel would hang after that, and if add debug message
> in lkvm tool, I could see it endlessly calls mmio emulation.

Yes, because there is nothing there that kvmtool can emulate.

> Another finding is that  during the host kernel booting, I didn't see
> hvc console is
> registered, but I already enabled CONFIG_HVC_DRIVER and
> CONFIG_VIRTIO_CONSOLE. Is there any other step needed to be done?

Why would you expect the *host* to have a hvc console? This is a guest
feature, not a host one.

> 
> BTW, my lkvm tool is from:
> https://github.com/virtualopensystems/linux-kvm-arm.git
> with some modification to add cortex-a53 support.

What is wrong with *mainline* kvmtool?

	M.
-- 
Jazz is not dead. It just smells funny...