Re: [PATCH v9 0/5] ARM Nested Virt Support

[Eric Auger <eric.auger@redhat.com>]

Hi Peter,

On 7/10/25 12:42 PM, Peter Maydell wrote:
> On Mon, 7 Jul 2025 at 17:41, Eric Auger <eric.auger@redhat.com> wrote:
>> This is candidate for 10.1.
>>
>> For gaining virt functionality in KVM accelerated L1, The host needs to
>> be booted with "kvm-arm.mode=nested" option and qemu needs to be invoked
>> with: -machine virt,virtualization=on.
>>
>> This series can be found at:
>> https://github.com/eauger/qemu/tree/v10.0.0-nv-v9
>> previous:
>> https://github.com/eauger/qemu/tree/v10.0.0-nv-v8
>
> Applied to target-arm.next, thanks. I'm going to squash in
> this change
>
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -2248,8 +2248,13 @@ static void machvirt_init(MachineState *machine)
>          exit(1);
>      }
>
> -    if (vms->virt && !(kvm_enabled() && kvm_arm_el2_supported()) &&
> -                     !tcg_enabled() && !qtest_enabled()) {
> +    if (vms->virt && kvm_enabled() && !kvm_arm_el2_supported()) {
> +        error_report("mach-virt: host kernel KVM does not support providing "
> +                     "Virtualization extensions to the guest CPU");
> +        exit(1);
> +    }
> +
> +    if (vms->virt && !kvm_enabled() && !tcg_enabled() && !qtest_enabled()) {
>          error_report("mach-virt: %s does not support providing "
>                       "Virtualization extensions to the guest CPU",
>                       current_accel_name());
>
> so we can distinguish "QEMU doesn't support KVM EL2" from
> "QEMU supports it but the kernel does not".

Sure.

Thanks!

Eric
>
> -- PMM
>