diff mbox series

[v2,6/8] vdpa_sim: use kthread worker

Message ID 20230302113421.174582-7-sgarzare@redhat.com
State New
Headers
Series vdpa_sim: add support for user VA |

Commit Message

Stefano Garzarella March 2, 2023, 11:34 a.m. UTC 
  Let's use our own kthread to run device jobs.
This allows us more flexibility, especially we can attach the kthread
to the user address space when vDPA uses user's VA.

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
---
 drivers/vdpa/vdpa_sim/vdpa_sim.h |  3 ++-
 drivers/vdpa/vdpa_sim/vdpa_sim.c | 17 ++++++++++++-----
 2 files changed, 14 insertions(+), 6 deletions(-)

Comments

Simon Horman March 2, 2023, 3:30 p.m. UTC | #1 
On Thu, Mar 02, 2023 at 12:34:19PM +0100, Stefano Garzarella wrote:
> Let's use our own kthread to run device jobs.
> This allows us more flexibility, especially we can attach the kthread
> to the user address space when vDPA uses user's VA.
> 
> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
> ---
>  drivers/vdpa/vdpa_sim/vdpa_sim.h |  3 ++-
>  drivers/vdpa/vdpa_sim/vdpa_sim.c | 17 ++++++++++++-----
>  2 files changed, 14 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.h b/drivers/vdpa/vdpa_sim/vdpa_sim.h
> index acee20faaf6a..ce83f9130a5d 100644
> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.h
> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.h
> @@ -57,7 +57,8 @@ struct vdpasim_dev_attr {
>  struct vdpasim {
>  	struct vdpa_device vdpa;
>  	struct vdpasim_virtqueue *vqs;
> -	struct work_struct work;
> +	struct kthread_worker *worker;
> +	struct kthread_work work;
>  	struct vdpasim_dev_attr dev_attr;
>  	/* spinlock to synchronize virtqueue state */
>  	spinlock_t lock;
> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> index a6ee830efc38..6feb29726c2a 100644
> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> @@ -11,8 +11,8 @@
>  #include <linux/module.h>
>  #include <linux/device.h>
>  #include <linux/kernel.h>
> +#include <linux/kthread.h>
>  #include <linux/slab.h>
> -#include <linux/sched.h>
>  #include <linux/dma-map-ops.h>
>  #include <linux/vringh.h>
>  #include <linux/vdpa.h>
> @@ -116,7 +116,7 @@ static void vdpasim_do_reset(struct vdpasim *vdpasim)
>  static const struct vdpa_config_ops vdpasim_config_ops;
>  static const struct vdpa_config_ops vdpasim_batch_config_ops;
>  
> -static void vdpasim_work_fn(struct work_struct *work)
> +static void vdpasim_work_fn(struct kthread_work *work)
>  {
>  	struct vdpasim *vdpasim = container_of(work, struct vdpasim, work);
>  
> @@ -159,7 +159,13 @@ struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr,
>  
>  	vdpasim = vdpa_to_sim(vdpa);
>  	vdpasim->dev_attr = *dev_attr;
> -	INIT_WORK(&vdpasim->work, vdpasim_work_fn);
> +
> +	kthread_init_work(&vdpasim->work, vdpasim_work_fn);
> +	vdpasim->worker = kthread_create_worker(0, "vDPA sim worker: %s",
> +						dev_attr->name);
> +	if (IS_ERR(vdpasim->worker))
> +		goto err_iommu;

Branching to err_iommu will result in a call to put_device(dev)...

> +
>  	spin_lock_init(&vdpasim->lock);
>  	spin_lock_init(&vdpasim->iommu_lock);

... but dev is not initialised until the line following this hunk,
which is:

	dev = &vdpasim->vdpa.dev;

In order to avoid leaking dev I _think_ the correct approach
is to move the initialisation of dev above the branch to
err_iommu, perhaps above the call to kthread_init_work()
is a good place.

This does move the assignment outside the locks above.
But I _think_ that is ok.

> @@ -212,7 +218,7 @@ EXPORT_SYMBOL_GPL(vdpasim_create);
>  
>  void vdpasim_schedule_work(struct vdpasim *vdpasim)
>  {
> -	schedule_work(&vdpasim->work);
> +	kthread_queue_work(vdpasim->worker, &vdpasim->work);
>  }
>  EXPORT_SYMBOL_GPL(vdpasim_schedule_work);
>  
> @@ -612,7 +618,8 @@ static void vdpasim_free(struct vdpa_device *vdpa)
>  	struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
>  	int i;
>  
> -	cancel_work_sync(&vdpasim->work);
> +	kthread_cancel_work_sync(&vdpasim->work);
> +	kthread_destroy_worker(vdpasim->worker);
>  
>  	for (i = 0; i < vdpasim->dev_attr.nvqs; i++) {
>  		vringh_kiov_cleanup(&vdpasim->vqs[i].out_iov);
> -- 
> 2.39.2
>
Stefano Garzarella March 2, 2023, 3:48 p.m. UTC | #2 
On Thu, Mar 02, 2023 at 04:30:04PM +0100, Simon Horman wrote:
>On Thu, Mar 02, 2023 at 12:34:19PM +0100, Stefano Garzarella wrote:
>> Let's use our own kthread to run device jobs.
>> This allows us more flexibility, especially we can attach the kthread
>> to the user address space when vDPA uses user's VA.
>>
>> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
>> ---
>>  drivers/vdpa/vdpa_sim/vdpa_sim.h |  3 ++-
>>  drivers/vdpa/vdpa_sim/vdpa_sim.c | 17 ++++++++++++-----
>>  2 files changed, 14 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.h b/drivers/vdpa/vdpa_sim/vdpa_sim.h
>> index acee20faaf6a..ce83f9130a5d 100644
>> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.h
>> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.h
>> @@ -57,7 +57,8 @@ struct vdpasim_dev_attr {
>>  struct vdpasim {
>>  	struct vdpa_device vdpa;
>>  	struct vdpasim_virtqueue *vqs;
>> -	struct work_struct work;
>> +	struct kthread_worker *worker;
>> +	struct kthread_work work;
>>  	struct vdpasim_dev_attr dev_attr;
>>  	/* spinlock to synchronize virtqueue state */
>>  	spinlock_t lock;
>> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
>> index a6ee830efc38..6feb29726c2a 100644
>> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
>> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
>> @@ -11,8 +11,8 @@
>>  #include <linux/module.h>
>>  #include <linux/device.h>
>>  #include <linux/kernel.h>
>> +#include <linux/kthread.h>
>>  #include <linux/slab.h>
>> -#include <linux/sched.h>
>>  #include <linux/dma-map-ops.h>
>>  #include <linux/vringh.h>
>>  #include <linux/vdpa.h>
>> @@ -116,7 +116,7 @@ static void vdpasim_do_reset(struct vdpasim *vdpasim)
>>  static const struct vdpa_config_ops vdpasim_config_ops;
>>  static const struct vdpa_config_ops vdpasim_batch_config_ops;
>>
>> -static void vdpasim_work_fn(struct work_struct *work)
>> +static void vdpasim_work_fn(struct kthread_work *work)
>>  {
>>  	struct vdpasim *vdpasim = container_of(work, struct vdpasim, work);
>>
>> @@ -159,7 +159,13 @@ struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr,
>>
>>  	vdpasim = vdpa_to_sim(vdpa);
>>  	vdpasim->dev_attr = *dev_attr;
>> -	INIT_WORK(&vdpasim->work, vdpasim_work_fn);
>> +
>> +	kthread_init_work(&vdpasim->work, vdpasim_work_fn);
>> +	vdpasim->worker = kthread_create_worker(0, "vDPA sim worker: %s",
>> +						dev_attr->name);
>> +	if (IS_ERR(vdpasim->worker))
>> +		goto err_iommu;
>
>Branching to err_iommu will result in a call to put_device(dev)...

Good catch!

>
>> +
>>  	spin_lock_init(&vdpasim->lock);
>>  	spin_lock_init(&vdpasim->iommu_lock);
>
>... but dev is not initialised until the line following this hunk,
>which is:
>
>	dev = &vdpasim->vdpa.dev;
>
>In order to avoid leaking dev I _think_ the correct approach
>is to move the initialisation of dev above the branch to
>err_iommu, perhaps above the call to kthread_init_work()
>is a good place.

Yep, I agree. I'll fix in v3.

Thanks,
Stefano

>
>This does move the assignment outside the locks above.
>But I _think_ that is ok.
>
>> @@ -212,7 +218,7 @@ EXPORT_SYMBOL_GPL(vdpasim_create);
>>
>>  void vdpasim_schedule_work(struct vdpasim *vdpasim)
>>  {
>> -	schedule_work(&vdpasim->work);
>> +	kthread_queue_work(vdpasim->worker, &vdpasim->work);
>>  }
>>  EXPORT_SYMBOL_GPL(vdpasim_schedule_work);
>>
>> @@ -612,7 +618,8 @@ static void vdpasim_free(struct vdpa_device *vdpa)
>>  	struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
>>  	int i;
>>
>> -	cancel_work_sync(&vdpasim->work);
>> +	kthread_cancel_work_sync(&vdpasim->work);
>> +	kthread_destroy_worker(vdpasim->worker);
>>
>>  	for (i = 0; i < vdpasim->dev_attr.nvqs; i++) {
>>  		vringh_kiov_cleanup(&vdpasim->vqs[i].out_iov);
>> --
>> 2.39.2
>>
>
kernel test robot March 5, 2023, 11:21 a.m. UTC | #3 
Hi Stefano,

I love your patch! Perhaps something to improve:

[auto build test WARNING on mst-vhost/linux-next]
[also build test WARNING on linus/master next-20230303]
[cannot apply to v6.2]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Stefano-Garzarella/vdpa-add-bind_mm-unbind_mm-callbacks/20230302-193850
base:   https://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost.git linux-next
patch link:    https://lore.kernel.org/r/20230302113421.174582-7-sgarzare%40redhat.com
patch subject: [PATCH v2 6/8] vdpa_sim: use kthread worker
config: i386-allyesconfig (https://download.01.org/0day-ci/archive/20230305/202303051841.bPAIzJRy-lkp@intel.com/config)
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project f28c006a5895fc0e329fe15fead81e37457cb1d1)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/5b2107457ac0e7b1bb0aa3635ebf13b02e82bb78
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Stefano-Garzarella/vdpa-add-bind_mm-unbind_mm-callbacks/20230302-193850
        git checkout 5b2107457ac0e7b1bb0aa3635ebf13b02e82bb78
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/net/wireless/ath/ath10k/ drivers/vdpa/vdpa_sim/ fs/erofs/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202303051841.bPAIzJRy-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/vdpa/vdpa_sim/vdpa_sim.c:166:6: warning: variable 'dev' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
           if (IS_ERR(vdpasim->worker))
               ^~~~~~~~~~~~~~~~~~~~~~~
   drivers/vdpa/vdpa_sim/vdpa_sim.c:213:13: note: uninitialized use occurs here
           put_device(dev);
                      ^~~
   drivers/vdpa/vdpa_sim/vdpa_sim.c:166:2: note: remove the 'if' if its condition is always false
           if (IS_ERR(vdpasim->worker))
           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
   drivers/vdpa/vdpa_sim/vdpa_sim.c:132:20: note: initialize the variable 'dev' to silence this warning
           struct device *dev;
                             ^
                              = NULL
   1 warning generated.


vim +166 drivers/vdpa/vdpa_sim/vdpa_sim.c

   125	
   126	struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr,
   127				       const struct vdpa_dev_set_config *config)
   128	{
   129		const struct vdpa_config_ops *ops;
   130		struct vdpa_device *vdpa;
   131		struct vdpasim *vdpasim;
   132		struct device *dev;
   133		int i, ret = -ENOMEM;
   134	
   135		if (!dev_attr->alloc_size)
   136			return ERR_PTR(-EINVAL);
   137	
   138		if (config->mask & BIT_ULL(VDPA_ATTR_DEV_FEATURES)) {
   139			if (config->device_features &
   140			    ~dev_attr->supported_features)
   141				return ERR_PTR(-EINVAL);
   142			dev_attr->supported_features =
   143				config->device_features;
   144		}
   145	
   146		if (batch_mapping)
   147			ops = &vdpasim_batch_config_ops;
   148		else
   149			ops = &vdpasim_config_ops;
   150	
   151		vdpa = __vdpa_alloc_device(NULL, ops,
   152					   dev_attr->ngroups, dev_attr->nas,
   153					   dev_attr->alloc_size,
   154					   dev_attr->name, false);
   155		if (IS_ERR(vdpa)) {
   156			ret = PTR_ERR(vdpa);
   157			goto err_alloc;
   158		}
   159	
   160		vdpasim = vdpa_to_sim(vdpa);
   161		vdpasim->dev_attr = *dev_attr;
   162	
   163		kthread_init_work(&vdpasim->work, vdpasim_work_fn);
   164		vdpasim->worker = kthread_create_worker(0, "vDPA sim worker: %s",
   165							dev_attr->name);
 > 166		if (IS_ERR(vdpasim->worker))
   167			goto err_iommu;
   168	
   169		spin_lock_init(&vdpasim->lock);
   170		spin_lock_init(&vdpasim->iommu_lock);
   171	
   172		dev = &vdpasim->vdpa.dev;
   173		dev->dma_mask = &dev->coherent_dma_mask;
   174		if (dma_set_mask_and_coherent(dev, DMA_BIT_MASK(64)))
   175			goto err_iommu;
   176		vdpasim->vdpa.mdev = dev_attr->mgmt_dev;
   177	
   178		vdpasim->config = kzalloc(dev_attr->config_size, GFP_KERNEL);
   179		if (!vdpasim->config)
   180			goto err_iommu;
   181	
   182		vdpasim->vqs = kcalloc(dev_attr->nvqs, sizeof(struct vdpasim_virtqueue),
   183				       GFP_KERNEL);
   184		if (!vdpasim->vqs)
   185			goto err_iommu;
   186	
   187		vdpasim->iommu = kmalloc_array(vdpasim->dev_attr.nas,
   188					       sizeof(*vdpasim->iommu), GFP_KERNEL);
   189		if (!vdpasim->iommu)
   190			goto err_iommu;
   191	
   192		vdpasim->iommu_pt = kmalloc_array(vdpasim->dev_attr.nas,
   193						  sizeof(*vdpasim->iommu_pt), GFP_KERNEL);
   194		if (!vdpasim->iommu_pt)
   195			goto err_iommu;
   196	
   197		for (i = 0; i < vdpasim->dev_attr.nas; i++)
   198			vhost_iotlb_init(&vdpasim->iommu[i], max_iotlb_entries, 0);
   199	
   200		vdpasim->buffer = kvmalloc(dev_attr->buffer_size, GFP_KERNEL);
   201		if (!vdpasim->buffer)
   202			goto err_iommu;
   203	
   204		for (i = 0; i < dev_attr->nvqs; i++)
   205			vringh_set_iotlb(&vdpasim->vqs[i].vring, &vdpasim->iommu[0],
   206					 &vdpasim->iommu_lock);
   207	
   208		vdpasim->vdpa.dma_dev = dev;
   209	
   210		return vdpasim;
   211	
   212	err_iommu:
   213		put_device(dev);
   214	err_alloc:
   215		return ERR_PTR(ret);
   216	}
   217	EXPORT_SYMBOL_GPL(vdpasim_create);
   218
Jason Wang March 14, 2023, 5:31 a.m. UTC | #4 
On Thu, Mar 2, 2023 at 7:35 PM Stefano Garzarella <sgarzare@redhat.com> wrote:
>
> Let's use our own kthread to run device jobs.
> This allows us more flexibility, especially we can attach the kthread
> to the user address space when vDPA uses user's VA.
>
> Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>

Acked-by: Jason Wang <jasowang@redhat.com>

Thanks



> ---
>  drivers/vdpa/vdpa_sim/vdpa_sim.h |  3 ++-
>  drivers/vdpa/vdpa_sim/vdpa_sim.c | 17 ++++++++++++-----
>  2 files changed, 14 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.h b/drivers/vdpa/vdpa_sim/vdpa_sim.h
> index acee20faaf6a..ce83f9130a5d 100644
> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.h
> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.h
> @@ -57,7 +57,8 @@ struct vdpasim_dev_attr {
>  struct vdpasim {
>         struct vdpa_device vdpa;
>         struct vdpasim_virtqueue *vqs;
> -       struct work_struct work;
> +       struct kthread_worker *worker;
> +       struct kthread_work work;
>         struct vdpasim_dev_attr dev_attr;
>         /* spinlock to synchronize virtqueue state */
>         spinlock_t lock;
> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> index a6ee830efc38..6feb29726c2a 100644
> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
> @@ -11,8 +11,8 @@
>  #include <linux/module.h>
>  #include <linux/device.h>
>  #include <linux/kernel.h>
> +#include <linux/kthread.h>
>  #include <linux/slab.h>
> -#include <linux/sched.h>
>  #include <linux/dma-map-ops.h>
>  #include <linux/vringh.h>
>  #include <linux/vdpa.h>
> @@ -116,7 +116,7 @@ static void vdpasim_do_reset(struct vdpasim *vdpasim)
>  static const struct vdpa_config_ops vdpasim_config_ops;
>  static const struct vdpa_config_ops vdpasim_batch_config_ops;
>
> -static void vdpasim_work_fn(struct work_struct *work)
> +static void vdpasim_work_fn(struct kthread_work *work)
>  {
>         struct vdpasim *vdpasim = container_of(work, struct vdpasim, work);
>
> @@ -159,7 +159,13 @@ struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr,
>
>         vdpasim = vdpa_to_sim(vdpa);
>         vdpasim->dev_attr = *dev_attr;
> -       INIT_WORK(&vdpasim->work, vdpasim_work_fn);
> +
> +       kthread_init_work(&vdpasim->work, vdpasim_work_fn);
> +       vdpasim->worker = kthread_create_worker(0, "vDPA sim worker: %s",
> +                                               dev_attr->name);
> +       if (IS_ERR(vdpasim->worker))
> +               goto err_iommu;
> +
>         spin_lock_init(&vdpasim->lock);
>         spin_lock_init(&vdpasim->iommu_lock);
>
> @@ -212,7 +218,7 @@ EXPORT_SYMBOL_GPL(vdpasim_create);
>
>  void vdpasim_schedule_work(struct vdpasim *vdpasim)
>  {
> -       schedule_work(&vdpasim->work);
> +       kthread_queue_work(vdpasim->worker, &vdpasim->work);
>  }
>  EXPORT_SYMBOL_GPL(vdpasim_schedule_work);
>
> @@ -612,7 +618,8 @@ static void vdpasim_free(struct vdpa_device *vdpa)
>         struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
>         int i;
>
> -       cancel_work_sync(&vdpasim->work);
> +       kthread_cancel_work_sync(&vdpasim->work);
> +       kthread_destroy_worker(vdpasim->worker);
>
>         for (i = 0; i < vdpasim->dev_attr.nvqs; i++) {
>                 vringh_kiov_cleanup(&vdpasim->vqs[i].out_iov);
> --
> 2.39.2
>
diff mbox series

Patch

diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.h b/drivers/vdpa/vdpa_sim/vdpa_sim.h
index acee20faaf6a..ce83f9130a5d 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.h
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.h
@@ -57,7 +57,8 @@  struct vdpasim_dev_attr {
 struct vdpasim {
 	struct vdpa_device vdpa;
 	struct vdpasim_virtqueue *vqs;
-	struct work_struct work;
+	struct kthread_worker *worker;
+	struct kthread_work work;
 	struct vdpasim_dev_attr dev_attr;
 	/* spinlock to synchronize virtqueue state */
 	spinlock_t lock;
diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
index a6ee830efc38..6feb29726c2a 100644
--- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
+++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
@@ -11,8 +11,8 @@ 
 #include <linux/module.h>
 #include <linux/device.h>
 #include <linux/kernel.h>
+#include <linux/kthread.h>
 #include <linux/slab.h>
-#include <linux/sched.h>
 #include <linux/dma-map-ops.h>
 #include <linux/vringh.h>
 #include <linux/vdpa.h>
@@ -116,7 +116,7 @@  static void vdpasim_do_reset(struct vdpasim *vdpasim)
 static const struct vdpa_config_ops vdpasim_config_ops;
 static const struct vdpa_config_ops vdpasim_batch_config_ops;
 
-static void vdpasim_work_fn(struct work_struct *work)
+static void vdpasim_work_fn(struct kthread_work *work)
 {
 	struct vdpasim *vdpasim = container_of(work, struct vdpasim, work);
 
@@ -159,7 +159,13 @@  struct vdpasim *vdpasim_create(struct vdpasim_dev_attr *dev_attr,
 
 	vdpasim = vdpa_to_sim(vdpa);
 	vdpasim->dev_attr = *dev_attr;
-	INIT_WORK(&vdpasim->work, vdpasim_work_fn);
+
+	kthread_init_work(&vdpasim->work, vdpasim_work_fn);
+	vdpasim->worker = kthread_create_worker(0, "vDPA sim worker: %s",
+						dev_attr->name);
+	if (IS_ERR(vdpasim->worker))
+		goto err_iommu;
+
 	spin_lock_init(&vdpasim->lock);
 	spin_lock_init(&vdpasim->iommu_lock);
 
@@ -212,7 +218,7 @@  EXPORT_SYMBOL_GPL(vdpasim_create);
 
 void vdpasim_schedule_work(struct vdpasim *vdpasim)
 {
-	schedule_work(&vdpasim->work);
+	kthread_queue_work(vdpasim->worker, &vdpasim->work);
 }
 EXPORT_SYMBOL_GPL(vdpasim_schedule_work);
 
@@ -612,7 +618,8 @@  static void vdpasim_free(struct vdpa_device *vdpa)
 	struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
 	int i;
 
-	cancel_work_sync(&vdpasim->work);
+	kthread_cancel_work_sync(&vdpasim->work);
+	kthread_destroy_worker(vdpasim->worker);
 
 	for (i = 0; i < vdpasim->dev_attr.nvqs; i++) {
 		vringh_kiov_cleanup(&vdpasim->vqs[i].out_iov);