diff mbox series

[v3,2/2] vfio/iommu_type1: Fix some sanity checks in detach group

Message ID 20210122092635.19900-3-zhukeqian1@huawei.com (mailing list archive)
State New, archived
Headers show
Series vfio/iommu_type1: some fixes | expand

Commit Message

Keqian Zhu Jan. 22, 2021, 9:26 a.m. UTC
vfio_sanity_check_pfn_list() is used to check whether pfn_list and
notifier are empty when remove the external domain, so it makes a
wrong assumption that only external domain will use the pinning
interface.

Now we apply the pfn_list check when a vfio_dma is removed and apply
the notifier check when all domains are removed.

Fixes: a54eb55045ae ("vfio iommu type1: Add support for mediated devices")
Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
---
 drivers/vfio/vfio_iommu_type1.c | 33 ++++++++++-----------------------
 1 file changed, 10 insertions(+), 23 deletions(-)

Comments

Alex Williamson Jan. 27, 2021, 11:46 p.m. UTC | #1
On Fri, 22 Jan 2021 17:26:35 +0800
Keqian Zhu <zhukeqian1@huawei.com> wrote:

> vfio_sanity_check_pfn_list() is used to check whether pfn_list and
> notifier are empty when remove the external domain, so it makes a
> wrong assumption that only external domain will use the pinning
> interface.
> 
> Now we apply the pfn_list check when a vfio_dma is removed and apply
> the notifier check when all domains are removed.
> 
> Fixes: a54eb55045ae ("vfio iommu type1: Add support for mediated devices")
> Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
> ---
>  drivers/vfio/vfio_iommu_type1.c | 33 ++++++++++-----------------------
>  1 file changed, 10 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index 161725395f2f..d8c10f508321 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -957,6 +957,7 @@ static long vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma,
>  
>  static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma)
>  {
> +	WARN_ON(!RB_EMPTY_ROOT(&dma->pfn_list));
>  	vfio_unmap_unpin(iommu, dma, true);
>  	vfio_unlink_dma(iommu, dma);
>  	put_task_struct(dma->task);
> @@ -2250,23 +2251,6 @@ static void vfio_iommu_unmap_unpin_reaccount(struct vfio_iommu *iommu)
>  	}
>  }
>  
> -static void vfio_sanity_check_pfn_list(struct vfio_iommu *iommu)
> -{
> -	struct rb_node *n;
> -
> -	n = rb_first(&iommu->dma_list);
> -	for (; n; n = rb_next(n)) {
> -		struct vfio_dma *dma;
> -
> -		dma = rb_entry(n, struct vfio_dma, node);
> -
> -		if (WARN_ON(!RB_EMPTY_ROOT(&dma->pfn_list)))
> -			break;
> -	}
> -	/* mdev vendor driver must unregister notifier */
> -	WARN_ON(iommu->notifier.head);
> -}
> -
>  /*
>   * Called when a domain is removed in detach. It is possible that
>   * the removed domain decided the iova aperture window. Modify the
> @@ -2366,10 +2350,10 @@ static void vfio_iommu_type1_detach_group(void *iommu_data,
>  			kfree(group);
>  
>  			if (list_empty(&iommu->external_domain->group_list)) {
> -				vfio_sanity_check_pfn_list(iommu);
> -
> -				if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu))
> +				if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu)) {
> +					WARN_ON(iommu->notifier.head);
>  					vfio_iommu_unmap_unpin_all(iommu);
> +				}
>  
>  				kfree(iommu->external_domain);
>  				iommu->external_domain = NULL;
> @@ -2403,10 +2387,12 @@ static void vfio_iommu_type1_detach_group(void *iommu_data,
>  		 */
>  		if (list_empty(&domain->group_list)) {
>  			if (list_is_singular(&iommu->domain_list)) {
> -				if (!iommu->external_domain)
> +				if (!iommu->external_domain) {
> +					WARN_ON(iommu->notifier.head);
>  					vfio_iommu_unmap_unpin_all(iommu);
> -				else
> +				} else {
>  					vfio_iommu_unmap_unpin_reaccount(iommu);
> +				}
>  			}
>  			iommu_domain_free(domain->domain);
>  			list_del(&domain->next);
> @@ -2488,9 +2474,10 @@ static void vfio_iommu_type1_release(void *iommu_data)
>  	struct vfio_iommu *iommu = iommu_data;
>  	struct vfio_domain *domain, *domain_tmp;
>  
> +	WARN_ON(iommu->notifier.head);

I don't see that this does any harm, but isn't it actually redundant?
It seems vfio-core only calls the iommu backend release function after
removing all the groups, so the tests in _detach_group should catch all
cases.  We're expecting the vfio bus/mdev driver to remove the notifier
when a device is closed, which necessarily occurs before detaching the
group.  Thanks,

Alex

> +
>  	if (iommu->external_domain) {
>  		vfio_release_domain(iommu->external_domain, true);
> -		vfio_sanity_check_pfn_list(iommu);
>  		kfree(iommu->external_domain);
>  	}
>
Keqian Zhu Jan. 28, 2021, 3:21 p.m. UTC | #2
On 2021/1/28 7:46, Alex Williamson wrote:
> On Fri, 22 Jan 2021 17:26:35 +0800
> Keqian Zhu <zhukeqian1@huawei.com> wrote:
> 
>> vfio_sanity_check_pfn_list() is used to check whether pfn_list and
>> notifier are empty when remove the external domain, so it makes a
>> wrong assumption that only external domain will use the pinning
>> interface.
>>
>> Now we apply the pfn_list check when a vfio_dma is removed and apply
>> the notifier check when all domains are removed.
>>
>> Fixes: a54eb55045ae ("vfio iommu type1: Add support for mediated devices")
>> Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
>> ---
>>  drivers/vfio/vfio_iommu_type1.c | 33 ++++++++++-----------------------
>>  1 file changed, 10 insertions(+), 23 deletions(-)
>>
>> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
>> index 161725395f2f..d8c10f508321 100644
>> --- a/drivers/vfio/vfio_iommu_type1.c
>> +++ b/drivers/vfio/vfio_iommu_type1.c
>> @@ -957,6 +957,7 @@ static long vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma,
>>  
>>  static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma)
>>  {
>> +	WARN_ON(!RB_EMPTY_ROOT(&dma->pfn_list));
>>  	vfio_unmap_unpin(iommu, dma, true);
>>  	vfio_unlink_dma(iommu, dma);
>>  	put_task_struct(dma->task);
>> @@ -2250,23 +2251,6 @@ static void vfio_iommu_unmap_unpin_reaccount(struct vfio_iommu *iommu)
>>  	}
>>  }
>>  
>> -static void vfio_sanity_check_pfn_list(struct vfio_iommu *iommu)
>> -{
>> -	struct rb_node *n;
>> -
>> -	n = rb_first(&iommu->dma_list);
>> -	for (; n; n = rb_next(n)) {
>> -		struct vfio_dma *dma;
>> -
>> -		dma = rb_entry(n, struct vfio_dma, node);
>> -
>> -		if (WARN_ON(!RB_EMPTY_ROOT(&dma->pfn_list)))
>> -			break;
>> -	}
>> -	/* mdev vendor driver must unregister notifier */
>> -	WARN_ON(iommu->notifier.head);
>> -}
>> -
>>  /*
>>   * Called when a domain is removed in detach. It is possible that
>>   * the removed domain decided the iova aperture window. Modify the
>> @@ -2366,10 +2350,10 @@ static void vfio_iommu_type1_detach_group(void *iommu_data,
>>  			kfree(group);
>>  
>>  			if (list_empty(&iommu->external_domain->group_list)) {
>> -				vfio_sanity_check_pfn_list(iommu);
>> -
>> -				if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu))
>> +				if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu)) {
>> +					WARN_ON(iommu->notifier.head);
>>  					vfio_iommu_unmap_unpin_all(iommu);
>> +				}
>>  
>>  				kfree(iommu->external_domain);
>>  				iommu->external_domain = NULL;
>> @@ -2403,10 +2387,12 @@ static void vfio_iommu_type1_detach_group(void *iommu_data,
>>  		 */
>>  		if (list_empty(&domain->group_list)) {
>>  			if (list_is_singular(&iommu->domain_list)) {
>> -				if (!iommu->external_domain)
>> +				if (!iommu->external_domain) {
>> +					WARN_ON(iommu->notifier.head);
>>  					vfio_iommu_unmap_unpin_all(iommu);
>> -				else
>> +				} else {
>>  					vfio_iommu_unmap_unpin_reaccount(iommu);
>> +				}
>>  			}
>>  			iommu_domain_free(domain->domain);
>>  			list_del(&domain->next);
>> @@ -2488,9 +2474,10 @@ static void vfio_iommu_type1_release(void *iommu_data)
>>  	struct vfio_iommu *iommu = iommu_data;
>>  	struct vfio_domain *domain, *domain_tmp;
>>  
>> +	WARN_ON(iommu->notifier.head);
> 
> I don't see that this does any harm, but isn't it actually redundant?
> It seems vfio-core only calls the iommu backend release function after
> removing all the groups, so the tests in _detach_group should catch all
> cases.  We're expecting the vfio bus/mdev driver to remove the notifier
> when a device is closed, which necessarily occurs before detaching the
> group.  Thanks,
> 
> Alex
Hi Alex,

Sorry that today I was busy at sending the smmu HTTU based dma dirty log tracking.
I will reply you tomorrow. Thanks!

Keqian.

> 
>> +
>>  	if (iommu->external_domain) {
>>  		vfio_release_domain(iommu->external_domain, true);
>> -		vfio_sanity_check_pfn_list(iommu);
>>  		kfree(iommu->external_domain);
>>  	}
>>  
> 
> .
>
Keqian Zhu Jan. 29, 2021, 7:47 a.m. UTC | #3
On 2021/1/28 7:46, Alex Williamson wrote:
> On Fri, 22 Jan 2021 17:26:35 +0800
> Keqian Zhu <zhukeqian1@huawei.com> wrote:
> 
>> vfio_sanity_check_pfn_list() is used to check whether pfn_list and
>> notifier are empty when remove the external domain, so it makes a
>> wrong assumption that only external domain will use the pinning
>> interface.
>>
>> Now we apply the pfn_list check when a vfio_dma is removed and apply
>> the notifier check when all domains are removed.
>>
>> Fixes: a54eb55045ae ("vfio iommu type1: Add support for mediated devices")
>> Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
>> ---
>>  drivers/vfio/vfio_iommu_type1.c | 33 ++++++++++-----------------------
>>  1 file changed, 10 insertions(+), 23 deletions(-)
>>
>> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
>> index 161725395f2f..d8c10f508321 100644
>> --- a/drivers/vfio/vfio_iommu_type1.c
>> +++ b/drivers/vfio/vfio_iommu_type1.c
>> @@ -957,6 +957,7 @@ static long vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma,
>>  
>>  static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma)
>>  {
>> +	WARN_ON(!RB_EMPTY_ROOT(&dma->pfn_list));
>>  	vfio_unmap_unpin(iommu, dma, true);
>>  	vfio_unlink_dma(iommu, dma);
>>  	put_task_struct(dma->task);
>> @@ -2250,23 +2251,6 @@ static void vfio_iommu_unmap_unpin_reaccount(struct vfio_iommu *iommu)
>>  	}
>>  }
>>  
>> -static void vfio_sanity_check_pfn_list(struct vfio_iommu *iommu)
>> -{
>> -	struct rb_node *n;
>> -
>> -	n = rb_first(&iommu->dma_list);
>> -	for (; n; n = rb_next(n)) {
>> -		struct vfio_dma *dma;
>> -
>> -		dma = rb_entry(n, struct vfio_dma, node);
>> -
>> -		if (WARN_ON(!RB_EMPTY_ROOT(&dma->pfn_list)))
>> -			break;
>> -	}
>> -	/* mdev vendor driver must unregister notifier */
>> -	WARN_ON(iommu->notifier.head);
>> -}
>> -
>>  /*
>>   * Called when a domain is removed in detach. It is possible that
>>   * the removed domain decided the iova aperture window. Modify the
>> @@ -2366,10 +2350,10 @@ static void vfio_iommu_type1_detach_group(void *iommu_data,
>>  			kfree(group);
>>  
>>  			if (list_empty(&iommu->external_domain->group_list)) {
>> -				vfio_sanity_check_pfn_list(iommu);
>> -
>> -				if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu))
>> +				if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu)) {
>> +					WARN_ON(iommu->notifier.head);
>>  					vfio_iommu_unmap_unpin_all(iommu);
>> +				}
>>  
>>  				kfree(iommu->external_domain);
>>  				iommu->external_domain = NULL;
>> @@ -2403,10 +2387,12 @@ static void vfio_iommu_type1_detach_group(void *iommu_data,
>>  		 */
>>  		if (list_empty(&domain->group_list)) {
>>  			if (list_is_singular(&iommu->domain_list)) {
>> -				if (!iommu->external_domain)
>> +				if (!iommu->external_domain) {
>> +					WARN_ON(iommu->notifier.head);
>>  					vfio_iommu_unmap_unpin_all(iommu);
>> -				else
>> +				} else {
>>  					vfio_iommu_unmap_unpin_reaccount(iommu);
>> +				}
>>  			}
>>  			iommu_domain_free(domain->domain);
>>  			list_del(&domain->next);
>> @@ -2488,9 +2474,10 @@ static void vfio_iommu_type1_release(void *iommu_data)
>>  	struct vfio_iommu *iommu = iommu_data;
>>  	struct vfio_domain *domain, *domain_tmp;
>>  
>> +	WARN_ON(iommu->notifier.head);
> 
> I don't see that this does any harm, but isn't it actually redundant?
> It seems vfio-core only calls the iommu backend release function after
> removing all the groups, so the tests in _detach_group should catch all
> cases.  We're expecting the vfio bus/mdev driver to remove the notifier
> when a device is closed, which necessarily occurs before detaching the
> group.  Thanks,
Right. Devices of a specific group must be closed before detach this group.
Detach the last group have checked this, so vfio_iommu_type1_release doesn't
need to do this check again.

Could you please queue this patch and delete this check btw? Thanks. ;-)

Keqian.

> 
> Alex
> 
>> +
>>  	if (iommu->external_domain) {
>>  		vfio_release_domain(iommu->external_domain, true);
>> -		vfio_sanity_check_pfn_list(iommu);
>>  		kfree(iommu->external_domain);
>>  	}
>>  
> 
> .
>
diff mbox series

Patch

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 161725395f2f..d8c10f508321 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -957,6 +957,7 @@  static long vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma,
 
 static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma)
 {
+	WARN_ON(!RB_EMPTY_ROOT(&dma->pfn_list));
 	vfio_unmap_unpin(iommu, dma, true);
 	vfio_unlink_dma(iommu, dma);
 	put_task_struct(dma->task);
@@ -2250,23 +2251,6 @@  static void vfio_iommu_unmap_unpin_reaccount(struct vfio_iommu *iommu)
 	}
 }
 
-static void vfio_sanity_check_pfn_list(struct vfio_iommu *iommu)
-{
-	struct rb_node *n;
-
-	n = rb_first(&iommu->dma_list);
-	for (; n; n = rb_next(n)) {
-		struct vfio_dma *dma;
-
-		dma = rb_entry(n, struct vfio_dma, node);
-
-		if (WARN_ON(!RB_EMPTY_ROOT(&dma->pfn_list)))
-			break;
-	}
-	/* mdev vendor driver must unregister notifier */
-	WARN_ON(iommu->notifier.head);
-}
-
 /*
  * Called when a domain is removed in detach. It is possible that
  * the removed domain decided the iova aperture window. Modify the
@@ -2366,10 +2350,10 @@  static void vfio_iommu_type1_detach_group(void *iommu_data,
 			kfree(group);
 
 			if (list_empty(&iommu->external_domain->group_list)) {
-				vfio_sanity_check_pfn_list(iommu);
-
-				if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu))
+				if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu)) {
+					WARN_ON(iommu->notifier.head);
 					vfio_iommu_unmap_unpin_all(iommu);
+				}
 
 				kfree(iommu->external_domain);
 				iommu->external_domain = NULL;
@@ -2403,10 +2387,12 @@  static void vfio_iommu_type1_detach_group(void *iommu_data,
 		 */
 		if (list_empty(&domain->group_list)) {
 			if (list_is_singular(&iommu->domain_list)) {
-				if (!iommu->external_domain)
+				if (!iommu->external_domain) {
+					WARN_ON(iommu->notifier.head);
 					vfio_iommu_unmap_unpin_all(iommu);
-				else
+				} else {
 					vfio_iommu_unmap_unpin_reaccount(iommu);
+				}
 			}
 			iommu_domain_free(domain->domain);
 			list_del(&domain->next);
@@ -2488,9 +2474,10 @@  static void vfio_iommu_type1_release(void *iommu_data)
 	struct vfio_iommu *iommu = iommu_data;
 	struct vfio_domain *domain, *domain_tmp;
 
+	WARN_ON(iommu->notifier.head);
+
 	if (iommu->external_domain) {
 		vfio_release_domain(iommu->external_domain, true);
-		vfio_sanity_check_pfn_list(iommu);
 		kfree(iommu->external_domain);
 	}