From: Julien Grall <julien@xen.org>
To: Jan Beulich <jbeulich@suse.com>
Cc: hongyxia@amazon.co.uk, iwj@xenproject.org,
Julien Grall <jgrall@amazon.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Kevin Tian <kevin.tian@intel.com>, Paul Durrant <paul@xen.org>,
xen-devel@lists.xenproject.org
Subject: Re: [PATCH for-4.15 v5 2/3] xen/x86: iommu: Ignore IOMMU mapping requests when a domain is dying
Date: Mon, 1 Mar 2021 09:21:01 +0000 [thread overview]
Message-ID: <78e3ec89-a022-c234-6c73-0abd2fb74f61@xen.org> (raw)
In-Reply-To: <1a386635-9c7d-3880-7e99-d87722fe5075@suse.com>
Hi Jan,
On 26/02/2021 13:30, Jan Beulich wrote:
> On 26.02.2021 11:56, Julien Grall wrote:
>> From: Julien Grall <jgrall@amazon.com>
>>
>> The new x86 IOMMU page-tables allocator will release the pages when
>> relinquishing the domain resources. However, this is not sufficient
>> when the domain is dying because nothing prevents page-table to be
>> allocated.
>>
>> As the domain is dying, it is not necessary to continue to modify the
>> IOMMU page-tables as they are going to be destroyed soon.
>>
>> At the moment, page-table allocates will only happen when iommu_map().
>> So after this change there will be no more page-table allocation
>> happening because we don't use superpage mappings yet when not sharing
>> page tables.
>>
>> In order to observe d->is_dying correctly, we need to rely on per-arch
>> locking, so the check to ignore IOMMU mapping is added on the per-driver
>> map_page() callback.
>>
>> Signed-off-by: Julien Grall <jgrall@amazon.com>
>
> Reviewed-by: Jan Beulich <jbeulich@suse.com>
Thanks!
>
> Does this also want a Fixes: tag (the same as patch 1)?
I think so. I will add it when committing the series.
Cheers,
--
Julien Grall
next prev parent reply other threads:[~2021-03-01 9:21 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-26 10:56 [PATCH for-4.15 v5 0/3] xen/iommu: Collection of bug fixes for IOMMU teardown Julien Grall
2021-02-26 10:56 ` [PATCH for-4.15 v5 1/3] xen/iommu: x86: Don't try to free page tables is the IOMMU is not enabled Julien Grall
2021-02-26 13:27 ` Jan Beulich
2021-02-26 10:56 ` [PATCH for-4.15 v5 2/3] xen/x86: iommu: Ignore IOMMU mapping requests when a domain is dying Julien Grall
2021-02-26 13:30 ` Jan Beulich
2021-03-01 9:21 ` Julien Grall [this message]
2021-03-01 2:52 ` Tian, Kevin
2021-02-26 10:56 ` [PATCH for-4.15 v5 3/3] xen/iommu: x86: Clear the root page-table before freeing the page-tables Julien Grall
2021-03-01 2:54 ` Tian, Kevin
2021-03-02 9:56 ` [PATCH for-4.15 v5 0/3] xen/iommu: Collection of bug fixes for IOMMU teardown Julien Grall
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