Re: [Xen-devel] [Patch v11 2/3] vt-d: synchronize for Device-TLB flush one by one

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 01.06.16 at 11:05, <quan.xu@xxxxxxxxx> wrote:
> From: Quan Xu <quan.xu@xxxxxxxxx>
> 
> Today we do Device-TLB flush synchronization after issuing flush
> requests for all ATS devices belonging to a VM. Doing so however
> imposes a limitation, i.e. that we can not figure out which flush
> request is blocked in the flush queue list, based on VT-d spec.
> 
> To prepare correct Device-TLB flush timeout handling in next patch,
> we change the behavior to synchronize for every Device-TLB flush
> request. So the Device-TLB flush interface is changed a little bit,
> by checking timeout within the function instead of outside of function.
> 
> Accordingly we also do a similar change for flush interfaces of
> IOTLB/IEC/Context, i.e. moving synchronization into the function.
> Since there is no user of a non-synced interface, we just rename
> existing ones with _sync suffix.
> 
> v11:
>    1. Add __must_check annotation to invalidate_sync().
>    2. Remove the redundant invalidate_sync() in flush_iotlb_qi().
>    3. Refactor invalidate_sync() to indicate whether we need to flush
>       device IOTLB or not (I'll change it back in next patch, as I'll
>       add a specific function - dev_invalidate_sync() for device IOTLB
>       invalidation).
> 
> Signed-off-by: Quan Xu <quan.xu@xxxxxxxxx>

Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>


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