Re: [PATCH v3 2/2] vfio/iommu_type1: Fix some sanity checks in detach group
On 2021/1/28 7:46, Alex Williamson wrote:
> On Fri, 22 Jan 2021 17:26:35 +0800
> Keqian Zhu 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
>> ---
>> 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(>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(>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(>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(>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(>group_list)) {
>> if (list_is_singular(>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(>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);
>> }
>>
>
> .
>
Re: [PATCH v3 2/2] vfio/iommu_type1: Fix some sanity checks in detach group
On 2021/1/28 7:46, Alex Williamson wrote:
> On Fri, 22 Jan 2021 17:26:35 +0800
> Keqian Zhu 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
>> ---
>> 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(>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(>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(>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(>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(>group_list)) {
>> if (list_is_singular(>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(>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);
>> }
>>
>
> .
>
Re: [PATCH v3 2/2] vfio/iommu_type1: Fix some sanity checks in detach group
On Fri, 22 Jan 2021 17:26:35 +0800
Keqian Zhu 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
> ---
> 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(>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(>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(>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(>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(>group_list)) {
> if (list_is_singular(>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(>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);
> }
>
[PATCH v3 2/2] vfio/iommu_type1: Fix some sanity checks in detach group
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
---
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(>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(>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(>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(>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(>group_list)) {
if (list_is_singular(>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(>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);
}
--
2.19.1
