Re: [Qemu-devel] Could not boot a guest vm from kvm mode based on APM X-Gene Host and latest qemu

[liang yan <liangy@hpe.com>]

On 09/16/2015 03:24 AM, Tushar Jagad wrote:
> Hi,
>
> On Mon, Sep 14, 2015 at 06:03:48PM -0600, liang yan wrote:
>> Hello, All,
>>
>> I am trying to enable kvm for a guest vm on an APM X-Gene Host with
>> latest qemu, but could not make it work.
>>
>> The host is APM X-Gene 8-core, Linux kernel is 4.1.0-rc7-1-arm64,
>>
>> Guest kernel is linux-3.16rc3
>>
>> QEMU is latest version
>>
>> Host has these dmesg info
>> [    2.708259] kvm [1]: GICH base=0x780c0000, GICV base=0x780e0000, IRQ=25
>> [    2.708327] kvm [1]: timer IRQ30
>> [    2.708335] kvm [1]: Hyp mode initialized successfully
>>
>> Host has dev/kvm.
>>
>> command-line is
>> aarch64-softmmu/qemu-system-aarch64 -machine virt,kernel_irqchip=off
>> -cpu cortex-a57 -machine accel=kvm -nographic -smp 1 -m 2048 -kernel
>> aarch64-linux-3.16rc3-buildroot.img  --append "console=ttyAMA0"
>>
>>
>> when using cpu "cortex-a57", got the error "kvm_init_vcpu failed:
>> Invalid argument"
> Currently, it is not possible to run qemu with a cpu type other than the
> host. I'm currently in the process of adding the necessary support and
> have posted the necessary RFC patches for kvm[1] and qemu[2].
>
> [1] http://comments.gmane.org/gmane.linux.ports.arm.kernel/438744
> [2] https://lists.gnu.org/archive/html/qemu-devel/2015-09/msg02374.html
> --
> Regards,
> Tushar

Hello, Tushar,

Thanks for your reply.

Actually, I already patched your code there, also used the command "-cpu 
cortex-a57,bpts=2,wpts=2" ,but did not change the output,
I am trying to check the KVM code from Linux kernel now.

By the way, I am very interested in your work here, feel free to let me 
know if there
are anything I can be involved.

Best,
Liang
>> when using cpu "host", got the error "Failed to retrieve host CPU features!"
>>
>> By the way, all the command line works well under "tcg" mode.
>> Anyone has a quick idea? Thanks in advance.
>>
>> Best,
>> Liang
>>
>>