Re: [PATCH] KVM: Enable hardware before doing arch VM initialization

[Christian Borntraeger]

On 23.09.20 20:57, Sean Christopherson wrote:
> Swap the order of hardware_enable_all() and kvm_arch_init_vm() to
> accommodate Intel's Trust Domain Extension (TDX), which needs VMX to be
> fully enabled during VM init in order to make SEAMCALLs.
> 
> This also provides consistent ordering between kvm_create_vm() and
> kvm_destroy_vm() with respect to calling kvm_arch_destroy_vm() and
> hardware_disable_all().
> 
> Cc: Marc Zyngier <maz@xxxxxxxxxx>
> Cc: James Morse <james.morse@xxxxxxx>
> Cc: Julien Thierry <julien.thierry.kdev@xxxxxxxxx>
> Cc: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> Cc: Huacai Chen <chenhc@xxxxxxxxxx>
> Cc: Aleksandar Markovic <aleksandar.qemu.devel@xxxxxxxxx>
> Cc: linux-mips@xxxxxxxxxxxxxxx
> Cc: Paul Mackerras <paulus@xxxxxxxxxx>
> Cc: kvm-ppc@xxxxxxxxxxxxxxx
> Cc: Christian Borntraeger <borntraeger@xxxxxxxxxx>
> Cc: Janosch Frank <frankja@xxxxxxxxxxxxx>
> Cc: David Hildenbrand <david@xxxxxxxxxx>
> Cc: Cornelia Huck <cohuck@xxxxxxxxxx>
> Cc: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
> Cc: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
> Cc: Wanpeng Li <wanpengli@xxxxxxxxxxx>
> Cc: Jim Mattson <jmattson@xxxxxxxxxx>
> Cc: Joerg Roedel <joro@xxxxxxxxxx>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
> ---
> 
> Obviously not required until the TDX series comes along, but IMO KVM
> should be consistent with respect to enabling and disabling virt support
> in hardware.
> 
> Tested only on Intel hardware.  Unless I missed something, this only
> affects x86, Arm and MIPS as hardware enabling is a nop for s390 and PPC.

Yes, looks fine from an s390 perspective.

Reviewed-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>