From: Julien Grall <julien@xen.org>
To: paul@xen.org, xen-devel@lists.xenproject.org
Cc: 'Paul Durrant' <pdurrant@amazon.com>,
'Daniel De Graaf' <dgdegra@tycho.nsa.gov>,
'Ian Jackson' <iwj@xenproject.org>, 'Wei Liu' <wl@xen.org>,
'Andrew Cooper' <andrew.cooper3@citrix.com>,
'George Dunlap' <george.dunlap@citrix.com>,
'Jan Beulich' <jbeulich@suse.com>,
'Stefano Stabellini' <sstabellini@kernel.org>
Subject: Re: [PATCH 2/5] iommu / domctl: introduce XEN_DOMCTL_iommu_ctl
Date: Tue, 20 Oct 2020 18:17:12 +0100 [thread overview]
Message-ID: <e37bdd4a-f483-9143-7860-81be31916aca@xen.org> (raw)
In-Reply-To: <002a01d6a5e8$c36bb5a0$4a4320e0$@xen.org>
Hi Paul,
On 19/10/2020 08:23, Paul Durrant wrote:
>> -----Original Message-----
>> From: Julien Grall <julien@xen.org>
>> Sent: 16 October 2020 16:47
>> To: Paul Durrant <paul@xen.org>; xen-devel@lists.xenproject.org
>> Cc: Paul Durrant <pdurrant@amazon.com>; Daniel De Graaf <dgdegra@tycho.nsa.gov>; Ian Jackson
>> <iwj@xenproject.org>; Wei Liu <wl@xen.org>; Andrew Cooper <andrew.cooper3@citrix.com>; George Dunlap
>> <george.dunlap@citrix.com>; Jan Beulich <jbeulich@suse.com>; Stefano Stabellini
>> <sstabellini@kernel.org>
>> Subject: Re: [PATCH 2/5] iommu / domctl: introduce XEN_DOMCTL_iommu_ctl
>>
>> Hi Paul,
>>
>> On 05/10/2020 10:49, Paul Durrant wrote:
>>> diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
>>> index 791f0a2592..75e855625a 100644
>>> --- a/xen/include/public/domctl.h
>>> +++ b/xen/include/public/domctl.h
>>> @@ -1130,6 +1130,18 @@ struct xen_domctl_vuart_op {
>>> */
>>> };
>>>
>>> +/*
>>> + * XEN_DOMCTL_iommu_ctl
>>> + *
>>> + * Control of VM IOMMU settings
>>> + */
>>> +
>>> +#define XEN_DOMCTL_IOMMU_INVALID 0
>>
>> I can't find any user of XEN_DOMCTL_IOMMU_INVALID. What's the purpose
>> for it?
>>
>
> It's just a placeholder. I think it's generally safer that a zero opcode value is invalid.
Thanks for the explanation. I first thought the goal would to somehow
invalidate the IOMMU :).
Anyway, it might be worth adding /* Reserved - should never be used */
on top.
Cheers,
--
Julien Grall
next prev parent reply other threads:[~2020-10-20 17:17 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-05 9:49 [PATCH 0/5] iommu page-table memory pool Paul Durrant
2020-10-05 9:49 ` [PATCH 1/5] libxl: remove separate calculation of IOMMU memory overhead Paul Durrant
2020-10-08 13:07 ` Wei Liu
2020-10-05 9:49 ` [PATCH 2/5] iommu / domctl: introduce XEN_DOMCTL_iommu_ctl Paul Durrant
2020-10-16 15:47 ` Julien Grall
2020-10-19 7:23 ` Paul Durrant
2020-10-19 7:29 ` Jan Beulich
2020-10-19 7:32 ` Paul Durrant
2020-10-20 17:17 ` Julien Grall [this message]
2020-10-05 9:49 ` [PATCH 3/5] libxl / iommu / domctl: introduce XEN_DOMCTL_IOMMU_SET_ALLOCATION Paul Durrant
2020-10-08 13:08 ` Wei Liu
2020-10-16 15:54 ` Julien Grall
2020-10-19 7:30 ` Paul Durrant
2020-10-30 16:45 ` Jan Beulich
2020-10-05 9:49 ` [PATCH 4/5] iommu: set 'hap_pt_share' and 'need_sync' flags earlier in iommu_domain_init() Paul Durrant
2020-10-16 16:07 ` Julien Grall
2020-10-30 16:11 ` Jan Beulich
2020-10-05 9:49 ` [PATCH 5/5] x86 / iommu: create a dedicated pool of page-table pages Paul Durrant
2020-10-30 16:43 ` Jan Beulich
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