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

[Tushar Jagad]

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

> 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
>
>