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Re: [PATCH 01/16] iommu: Add checks before calling iommu suspend/resume
- To: Mykola Kvach <xakep.amatop@xxxxxxxxx>
- From: Jan Beulich <jbeulich@xxxxxxxx>
- Date: Wed, 19 Mar 2025 13:45:56 +0100
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- Cc: Mykyta Poturai <mykyta_poturai@xxxxxxxx>, Roger Pau Monné <roger.pau@xxxxxxxxxx>, Mykola Kvach <mykola_kvach@xxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxxx
- Delivery-date: Wed, 19 Mar 2025 12:46:01 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
On 19.03.2025 13:01, Mykola Kvach wrote:
> Hi,
>
> On Wed, Mar 5, 2025 at 6:45 PM Jan Beulich <jbeulich@xxxxxxxx> wrote:
>>
>> On 05.03.2025 10:11, Mykola Kvach wrote:
>>> --- a/xen/drivers/passthrough/iommu.c
>>> +++ b/xen/drivers/passthrough/iommu.c
>>> @@ -613,7 +613,7 @@ int __init iommu_setup(void)
>>>
>>> int iommu_suspend(void)
>>> {
>>> - if ( iommu_enabled )
>>> + if ( iommu_enabled && iommu_get_ops() && iommu_get_ops()->suspend )
>>> return iommu_call(iommu_get_ops(), suspend);
>>>
>>> return 0;
>>> @@ -621,7 +621,7 @@ int iommu_suspend(void)
>>>
>>> void iommu_resume(void)
>>> {
>>> - if ( iommu_enabled )
>>> + if ( iommu_enabled && iommu_get_ops() && iommu_get_ops()->resume )
>>> iommu_vcall(iommu_get_ops(), resume);
>>> }
>>
>> When iommu_enabled is true, surely iommu_get_ops() is required to return
>> non-NULL?
>
> As far as I can see, in some cases, the handler is still checked even
> if iommu_enabled
> is true, such as in the case of the iommu_quiesce call.
You say "handler" and also refer to a case where the handler is checked.
My comment was about the bare iommu_get_ops() though.
> However, it
> might be better to drop
> this patch from the current patch series or add a patch that
> introduces the handlers.
Only if they're not merely stubs.
Jan
|
