linux-kernel - Re: [PATCH v2 2/9] kvm-vfio: Decouple only when we match a group

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Date:   Tue, 20 Jun 2017 12:34:57 +1000
From:   Alexey Kardashevskiy <aik@...abs.ru>
To:     Alex Williamson <alex.williamson@...hat.com>, kvm@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        eric.auger@...hat.com, Paolo Bonzini <pbonzini@...hat.com>
Subject: Re: [PATCH v2 2/9] kvm-vfio: Decouple only when we match a group

On 20/06/17 03:14, Alex Williamson wrote:
> Unset-KVM and decrement-assignment only when we find the group in our
> list.  Otherwise we can get out of sync if the user triggers this for
> groups that aren't currently on our list.
> 
> Signed-off-by: Alex Williamson <alex.williamson@...hat.com>
> Cc: Paolo Bonzini <pbonzini@...hat.com>
> Cc: Eric Auger <eric.auger@...hat.com>
> Cc: Alexey Kardashevskiy <aik@...abs.ru>
> Cc: stable@...r.kernel.org
> ---
>  virt/kvm/vfio.c |   12 +++++-------
>  1 file changed, 5 insertions(+), 7 deletions(-)
> 
> diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c
> index 37d9118fd84b..f1b0b7bca9a9 100644
> --- a/virt/kvm/vfio.c
> +++ b/virt/kvm/vfio.c
> @@ -246,21 +246,19 @@ static int kvm_vfio_set_group(struct kvm_device *dev, long attr, u64 arg)
>  				continue;
>  
>  			list_del(&kvg->node);
> +			kvm_arch_end_assignment(dev->kvm);
> +#ifdef CONFIG_SPAPR_TCE_IOMMU
> +			kvm_spapr_tce_release_vfio_group(dev->kvm, vfio_group);
> +#endif
> +			kvm_vfio_group_set_kvm(kvg->vfio_group, NULL);
>  			kvm_vfio_group_put_external_user(kvg->vfio_group);
>  			kfree(kvg);
>  			ret = 0;
>  			break;
>  		}
>  
> -		kvm_arch_end_assignment(dev->kvm);
> -
>  		mutex_unlock(&kv->lock);
>  
> -#ifdef CONFIG_SPAPR_TCE_IOMMU
> -		kvm_spapr_tce_release_vfio_group(dev->kvm, vfio_group);
> -#endif
> -		kvm_vfio_group_set_kvm(vfio_group, NULL);


Tiny nit: vfio_group becomes kvg->vfio_group in kvm_vfio_group_set_kvm()
and does not in kvm_spapr_tce_release_vfio_group().


Anyway,

Reviewed-by: Alexey Kardashevskiy <aik@...abs.ru>



> -
>  		kvm_vfio_group_put_external_user(vfio_group);
>  
>  		kvm_vfio_update_coherency(dev);
> 


-- 
Alexey