RE: [for-4.15][PATCH v2 4/5] xen/iommu: x86: Don't leak the IOMMU page-tables

[Paul Durrant <xadimgnik@xxxxxxxxx>]

> -----Original Message-----
> From: Julien Grall <julien@xxxxxxx>
> Sent: 09 February 2021 15:28
> To: xen-devel@xxxxxxxxxxxxxxxxxxxx
> Cc: hongyxia@xxxxxxxxxxxx; iwj@xxxxxxxxxxxxxx; Julien Grall 
> <jgrall@xxxxxxxxxx>; Jan Beulich
> <jbeulich@xxxxxxxx>; Paul Durrant <paul@xxxxxxx>
> Subject: [for-4.15][PATCH v2 4/5] xen/iommu: x86: Don't leak the IOMMU 
> page-tables
> 
> From: Julien Grall <jgrall@xxxxxxxxxx>
> 
> The new IOMMU page-tables allocator will release the pages when
> relinquish the domain resources. However, this is not sufficient when
> the domain is dying because nothing prevents page-table to be allocated.
> 
> iommu_alloc_pgtable() is now checking if the domain is dying before
> adding the page in the list. We are relying on &hd->arch.pgtables.lock
> to synchronize d->is_dying.
> 
> Take the opportunity to check in arch_iommu_domain_destroy() that all
> that page tables have been freed.
> 
> Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx>
> 

Reviewed-by: Paul Durrant <paul@xxxxxxx>