RE: [PATCH 01/10] kvm/vfio: Move KVM_DEV_VFIO_GROUP_* ioctls into functions

["Tian, Kevin" <kevin.tian@intel.com>]

> From: Jason Gunthorpe <jgg@nvidia.com>
> Sent: Friday, April 15, 2022 2:46 AM
> 
> To make it easier to read and change in following patches.
> 
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

Reviewed-by: Kevin Tian <kevin.tian@intel.com>

> ---
>  virt/kvm/vfio.c | 271 ++++++++++++++++++++++++++----------------------
>  1 file changed, 146 insertions(+), 125 deletions(-)
> 
> This is best viewed using 'git diff -b' to ignore the whitespace change.
> 
> diff --git a/virt/kvm/vfio.c b/virt/kvm/vfio.c
> index 8fcbc50221c2d2..a1167ab7a2246f 100644
> --- a/virt/kvm/vfio.c
> +++ b/virt/kvm/vfio.c
> @@ -181,149 +181,170 @@ static void kvm_vfio_update_coherency(struct
> kvm_device *dev)
>  	mutex_unlock(&kv->lock);
>  }
> 
> -static int kvm_vfio_set_group(struct kvm_device *dev, long attr, u64 arg)
> +static int kvm_vfio_group_add(struct kvm_device *dev, unsigned int fd)
>  {
>  	struct kvm_vfio *kv = dev->private;
>  	struct vfio_group *vfio_group;
>  	struct kvm_vfio_group *kvg;
> -	int32_t __user *argp = (int32_t __user *)(unsigned long)arg;
>  	struct fd f;
> -	int32_t fd;
>  	int ret;
> 
> +	f = fdget(fd);
> +	if (!f.file)
> +		return -EBADF;
> +
> +	vfio_group = kvm_vfio_group_get_external_user(f.file);
> +	fdput(f);
> +
> +	if (IS_ERR(vfio_group))
> +		return PTR_ERR(vfio_group);
> +
> +	mutex_lock(&kv->lock);
> +
> +	list_for_each_entry(kvg, &kv->group_list, node) {
> +		if (kvg->vfio_group == vfio_group) {
> +			ret = -EEXIST;
> +			goto err_unlock;
> +		}
> +	}
> +
> +	kvg = kzalloc(sizeof(*kvg), GFP_KERNEL_ACCOUNT);
> +	if (!kvg) {
> +		ret = -ENOMEM;
> +		goto err_unlock;
> +	}
> +
> +	list_add_tail(&kvg->node, &kv->group_list);
> +	kvg->vfio_group = vfio_group;
> +
> +	kvm_arch_start_assignment(dev->kvm);
> +
> +	mutex_unlock(&kv->lock);
> +
> +	kvm_vfio_group_set_kvm(vfio_group, dev->kvm);
> +	kvm_vfio_update_coherency(dev);
> +
> +	return 0;
> +err_unlock:
> +	mutex_unlock(&kv->lock);
> +	kvm_vfio_group_put_external_user(vfio_group);
> +	return ret;
> +}
> +
> +static int kvm_vfio_group_del(struct kvm_device *dev, unsigned int fd)
> +{
> +	struct kvm_vfio *kv = dev->private;
> +	struct kvm_vfio_group *kvg;
> +	struct fd f;
> +	int ret;
> +
> +	f = fdget(fd);
> +	if (!f.file)
> +		return -EBADF;
> +
> +	ret = -ENOENT;
> +
> +	mutex_lock(&kv->lock);
> +
> +	list_for_each_entry(kvg, &kv->group_list, node) {
> +		if (!kvm_vfio_external_group_match_file(kvg->vfio_group,
> +							f.file))
> +			continue;
> +
> +		list_del(&kvg->node);
> +		kvm_arch_end_assignment(dev->kvm);
> +#ifdef CONFIG_SPAPR_TCE_IOMMU
> +		kvm_spapr_tce_release_vfio_group(dev->kvm, kvg-
> >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;
> +	}
> +
> +	mutex_unlock(&kv->lock);
> +
> +	fdput(f);
> +
> +	kvm_vfio_update_coherency(dev);
> +
> +	return ret;
> +}
> +
> +#ifdef CONFIG_SPAPR_TCE_IOMMU
> +static int kvm_vfio_group_set_spapr_tce(struct kvm_device *dev,
> +					void __user *arg)
> +{
> +	struct kvm_vfio_spapr_tce param;
> +	struct kvm_vfio *kv = dev->private;
> +	struct vfio_group *vfio_group;
> +	struct kvm_vfio_group *kvg;
> +	struct fd f;
> +	struct iommu_group *grp;
> +	int ret;
> +
> +	if (copy_from_user(&param, arg, sizeof(struct kvm_vfio_spapr_tce)))
> +		return -EFAULT;
> +
> +	f = fdget(param.groupfd);
> +	if (!f.file)
> +		return -EBADF;
> +
> +	vfio_group = kvm_vfio_group_get_external_user(f.file);
> +	fdput(f);
> +
> +	if (IS_ERR(vfio_group))
> +		return PTR_ERR(vfio_group);
> +
> +	grp = kvm_vfio_group_get_iommu_group(vfio_group);
> +	if (WARN_ON_ONCE(!grp)) {
> +		ret = -EIO;
> +		goto err_put_external;
> +	}
> +
> +	ret = -ENOENT;
> +
> +	mutex_lock(&kv->lock);
> +
> +	list_for_each_entry(kvg, &kv->group_list, node) {
> +		if (kvg->vfio_group != vfio_group)
> +			continue;
> +
> +		ret = kvm_spapr_tce_attach_iommu_group(dev->kvm,
> param.tablefd,
> +						       grp);
> +		break;
> +	}
> +
> +	mutex_unlock(&kv->lock);
> +
> +	iommu_group_put(grp);
> +err_put_external:
> +	kvm_vfio_group_put_external_user(vfio_group);
> +	return ret;
> +}
> +#endif
> +
> +static int kvm_vfio_set_group(struct kvm_device *dev, long attr, u64 arg)
> +{
> +	int32_t __user *argp = (int32_t __user *)(unsigned long)arg;
> +	int32_t fd;
> +
>  	switch (attr) {
>  	case KVM_DEV_VFIO_GROUP_ADD:
>  		if (get_user(fd, argp))
>  			return -EFAULT;
> -
> -		f = fdget(fd);
> -		if (!f.file)
> -			return -EBADF;
> -
> -		vfio_group = kvm_vfio_group_get_external_user(f.file);
> -		fdput(f);
> -
> -		if (IS_ERR(vfio_group))
> -			return PTR_ERR(vfio_group);
> -
> -		mutex_lock(&kv->lock);
> -
> -		list_for_each_entry(kvg, &kv->group_list, node) {
> -			if (kvg->vfio_group == vfio_group) {
> -				mutex_unlock(&kv->lock);
> -
> 	kvm_vfio_group_put_external_user(vfio_group);
> -				return -EEXIST;
> -			}
> -		}
> -
> -		kvg = kzalloc(sizeof(*kvg), GFP_KERNEL_ACCOUNT);
> -		if (!kvg) {
> -			mutex_unlock(&kv->lock);
> -			kvm_vfio_group_put_external_user(vfio_group);
> -			return -ENOMEM;
> -		}
> -
> -		list_add_tail(&kvg->node, &kv->group_list);
> -		kvg->vfio_group = vfio_group;
> -
> -		kvm_arch_start_assignment(dev->kvm);
> -
> -		mutex_unlock(&kv->lock);
> -
> -		kvm_vfio_group_set_kvm(vfio_group, dev->kvm);
> -
> -		kvm_vfio_update_coherency(dev);
> -
> -		return 0;
> +		return kvm_vfio_group_add(dev, fd);
> 
>  	case KVM_DEV_VFIO_GROUP_DEL:
>  		if (get_user(fd, argp))
>  			return -EFAULT;
> +		return kvm_vfio_group_del(dev, fd);
> 
> -		f = fdget(fd);
> -		if (!f.file)
> -			return -EBADF;
> -
> -		ret = -ENOENT;
> -
> -		mutex_lock(&kv->lock);
> -
> -		list_for_each_entry(kvg, &kv->group_list, node) {
> -			if (!kvm_vfio_external_group_match_file(kvg-
> >vfio_group,
> -								f.file))
> -				continue;
> -
> -			list_del(&kvg->node);
> -			kvm_arch_end_assignment(dev->kvm);
>  #ifdef CONFIG_SPAPR_TCE_IOMMU
> -			kvm_spapr_tce_release_vfio_group(dev->kvm,
> -							 kvg->vfio_group);
> +	case KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE:
> +		return kvm_vfio_group_set_spapr_tce(dev, (void __user
> *)arg);
>  #endif
> -			kvm_vfio_group_set_kvm(kvg->vfio_group, NULL);
> -			kvm_vfio_group_put_external_user(kvg->vfio_group);
> -			kfree(kvg);
> -			ret = 0;
> -			break;
> -		}
> -
> -		mutex_unlock(&kv->lock);
> -
> -		fdput(f);
> -
> -		kvm_vfio_update_coherency(dev);
> -
> -		return ret;
> -
> -#ifdef CONFIG_SPAPR_TCE_IOMMU
> -	case KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE: {
> -		struct kvm_vfio_spapr_tce param;
> -		struct kvm_vfio *kv = dev->private;
> -		struct vfio_group *vfio_group;
> -		struct kvm_vfio_group *kvg;
> -		struct fd f;
> -		struct iommu_group *grp;
> -
> -		if (copy_from_user(&param, (void __user *)arg,
> -				sizeof(struct kvm_vfio_spapr_tce)))
> -			return -EFAULT;
> -
> -		f = fdget(param.groupfd);
> -		if (!f.file)
> -			return -EBADF;
> -
> -		vfio_group = kvm_vfio_group_get_external_user(f.file);
> -		fdput(f);
> -
> -		if (IS_ERR(vfio_group))
> -			return PTR_ERR(vfio_group);
> -
> -		grp = kvm_vfio_group_get_iommu_group(vfio_group);
> -		if (WARN_ON_ONCE(!grp)) {
> -			kvm_vfio_group_put_external_user(vfio_group);
> -			return -EIO;
> -		}
> -
> -		ret = -ENOENT;
> -
> -		mutex_lock(&kv->lock);
> -
> -		list_for_each_entry(kvg, &kv->group_list, node) {
> -			if (kvg->vfio_group != vfio_group)
> -				continue;
> -
> -			ret = kvm_spapr_tce_attach_iommu_group(dev-
> >kvm,
> -					param.tablefd, grp);
> -			break;
> -		}
> -
> -		mutex_unlock(&kv->lock);
> -
> -		iommu_group_put(grp);
> -		kvm_vfio_group_put_external_user(vfio_group);
> -
> -		return ret;
> -	}
> -#endif /* CONFIG_SPAPR_TCE_IOMMU */
>  	}
> 
>  	return -ENXIO;
> --
> 2.35.1