Re: [PATCH] KVM: arm/arm64: ensure vcpu target is unset on reset failure

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

On Thu, 04 Apr 2019 18:42:30 +0100,
Andrew Jones <drjones@redhat.com> wrote:
> 
> A failed KVM_ARM_VCPU_INIT, should not set the vcpu target,
> as the vcpu target is used by kvm_vcpu_initialized() to
> determine if other vcpu ioctls may proceed. We need to set
> the target before calling kvm_reset_vcpu(), but if that call
> fails, we should then unset it.
> 
> Signed-off-by: Andrew Jones <drjones@redhat.com>
> ---
>  virt/kvm/arm/arm.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
> index 99c37384ba7b..7e5724ae1efd 100644
> --- a/virt/kvm/arm/arm.c
> +++ b/virt/kvm/arm/arm.c
> @@ -934,7 +934,7 @@ int kvm_vm_ioctl_irq_line(struct kvm *kvm, struct kvm_irq_level *irq_level,
>  static int kvm_vcpu_set_target(struct kvm_vcpu *vcpu,
>  			       const struct kvm_vcpu_init *init)
>  {
> -	unsigned int i;
> +	unsigned int i, ret;
>  	int phys_target = kvm_target_cpu();
>  
>  	if (init->target != phys_target)
> @@ -969,9 +969,15 @@ static int kvm_vcpu_set_target(struct kvm_vcpu *vcpu,
>  	vcpu->arch.target = phys_target;
>  
>  	/* Now we know what it is, we can reset it. */
> -	return kvm_reset_vcpu(vcpu);
> -}
> +	ret = kvm_reset_vcpu(vcpu);
> +	if (ret) {
> +		vcpu->arch.target = -1;
> +		bitmap_zero(vcpu->arch.features, KVM_VCPU_MAX_FEATURES);
> +		return ret;

This return could trivially be removed...

> +	}
>  
> +	return 0;
> +}

... and this turned into 'return ret'.

I've tentatively applied this to the 5.1-fixes branch. Let me know if
you're OK with it.

Thanks,

	M.

-- 
Jazz is not dead, it just smell funny.