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

From: Alexey Kardashevskiy
Date: Mon Jun 19 2017 - 22:35:28 EST


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@xxxxxxxxxx>
> Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> Cc: Eric Auger <eric.auger@xxxxxxxxxx>
> Cc: Alexey Kardashevskiy <aik@xxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> ---
> 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@xxxxxxxxx>



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


--
Alexey