From: George Dunlap <george.dunlap@eu.citrix.com>
To: Jan Beulich <JBeulich@suse.com>, Tiejun Chen <tiejun.chen@intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>, Keir Fraser <keir@xen.org>,
Ian Campbell <ian.campbell@citrix.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Tim Deegan <tim@xen.org>,
"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>,
Stefano Stabellini <stefano.stabellini@citrix.com>,
Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
Yang Zhang <yang.z.zhang@intel.com>,
Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>
Subject: Re: [v7][PATCH 03/16] xen/passthrough: extend hypercall to support rdm reservation policy
Date: Tue, 14 Jul 2015 14:25:42 +0100 [thread overview]
Message-ID: <55A50DD6.4090104@eu.citrix.com> (raw)
In-Reply-To: <55A5128F0200007800090A59@mail.emea.novell.com>
On 07/14/2015 12:45 PM, Jan Beulich wrote:
>>>> On 14.07.15 at 13:30, <george.dunlap@eu.citrix.com> wrote:
>> On 07/14/2015 11:53 AM, Chen, Tiejun wrote:
>>>> The way this sort of thing is defined in the rest of domctl.h is like
>>>> this:
>>>>
>>>> #define _XEN_DOMCTL_CDF_hvm_guest 0
>>>> #define XEN_DOMCTL_CDF_hvm_guest (1U<<_XEN_DOMCTL_CDF_hvm_guest)
>>>>
>>>> So the above should be
>>>>
>>>> #define _XEN_DOMCTL_DEV_RDM_RELAXED 0
>>>> #define XEN_DOMCTL_DEV_RDM_RELAXED (1U<<_XEN_DOMCTL_DEV_RDM_RELAXED)
>>>>
>>>> And then your check in iommu_do_pci_domctl() would look like
>>>>
>>>> if (flag & ~XEN_DOMCTL_DEV_RDM_RELAXED)
>>>>
>>>> And if we end up adding any extra flags, we just | them into the above
>>>> conditional, as is done in, for example, the XEN_DOMCTL_createdomain
>>>> case in xen/common/domctl.c:do_domctl().
>>>>
>>>
>>> Seems Jan didn't like this way IIRC, so I hope Jan also can have a look
>>> at this beforehand :)
>>
>> I think Jan thought that the MASK value you defined wasn't meant to be a
>> single flag, but for all the flags; i.e., that if we added flags in bits
>> 1 and 2, that MASK would become 0x7 rather than 0x1. And I agree that
>> there's not much point to having such a mask defined in the public header.
>>
>> But what I'm doing above is making explicit what you have already; i.e.,
>> you just set XEN_DOMCTL_DEV_RDM_RELAXED to '1'; the reader has to sort
>> of infer that the reason '1' is chosen is that it's setting bit 0.
>> Doing it the way I suggest makes it more clear that this is meant to be
>> a bitfield, and '0' has been allocated.
>>
>> Please correct me if I'm wrong, Jan.
>
> Indeed my primary objection was to what you describe. That said,
> I'm not too happy with what you propose now either. Not only do
> I view this (bit-pos,bit-mask) tuple as redundant unless one actually
> needs both in certain places (which doesn't seem to be the case
> here), but the naming also conflicts with the C standard (reserving
> identifiers starting with underscore and an upper case letter). Just
> like said in various other cases - we've got many examples of such
> violations already, but I'd prefer not to make the situation worse.
>
> IOW I'd prefer to go with just
>
> #define XEN_DOMCTL_DEV_RDM_RELAXED 1
Very well.
-George
next prev parent reply other threads:[~2015-07-14 13:25 UTC|newest]
Thread overview: 119+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-09 5:33 [v7][PATCH 00/16] Fix RMRR Tiejun Chen
2015-07-09 5:33 ` [v7][PATCH 01/16] xen: introduce XENMEM_reserved_device_memory_map Tiejun Chen
2015-07-09 5:33 ` [v7][PATCH 02/16] xen/vtd: create RMRR mapping Tiejun Chen
2015-07-09 5:33 ` [v7][PATCH 03/16] xen/passthrough: extend hypercall to support rdm reservation policy Tiejun Chen
2015-07-10 13:26 ` George Dunlap
2015-07-10 15:01 ` Jan Beulich
2015-07-10 15:07 ` George Dunlap
2015-07-13 6:37 ` Chen, Tiejun
2015-07-13 5:57 ` Chen, Tiejun
2015-07-13 6:47 ` Chen, Tiejun
2015-07-13 8:57 ` Jan Beulich
2015-07-14 10:46 ` George Dunlap
2015-07-14 10:53 ` Chen, Tiejun
2015-07-14 11:30 ` George Dunlap
2015-07-14 11:45 ` Jan Beulich
2015-07-14 13:25 ` George Dunlap [this message]
2015-07-09 5:33 ` [v7][PATCH 04/16] xen: enable XENMEM_memory_map in hvm Tiejun Chen
2015-07-09 5:33 ` [v7][PATCH 05/16] hvmloader: get guest memory map into memory_map[] Tiejun Chen
2015-07-10 13:49 ` George Dunlap
2015-07-13 7:03 ` Chen, Tiejun
2015-07-09 5:33 ` [v7][PATCH 06/16] hvmloader/pci: skip reserved ranges Tiejun Chen
2015-07-13 13:12 ` Jan Beulich
2015-07-14 6:39 ` Chen, Tiejun
2015-07-14 9:27 ` Jan Beulich
2015-07-14 10:54 ` Chen, Tiejun
2015-07-14 11:50 ` Jan Beulich
2015-07-15 0:55 ` Chen, Tiejun
2015-07-15 4:27 ` Chen, Tiejun
2015-07-15 8:34 ` Jan Beulich
2015-07-15 8:59 ` Chen, Tiejun
2015-07-15 9:10 ` Chen, Tiejun
2015-07-15 9:27 ` Jan Beulich
2015-07-15 10:34 ` Chen, Tiejun
2015-07-15 11:25 ` Jan Beulich
2015-07-15 11:34 ` Chen, Tiejun
2015-07-15 13:56 ` George Dunlap
2015-07-15 16:14 ` George Dunlap
2015-07-16 2:05 ` Chen, Tiejun
2015-07-16 9:40 ` George Dunlap
2015-07-16 10:01 ` Chen, Tiejun
2015-07-15 11:05 ` George Dunlap
2015-07-15 11:20 ` Chen, Tiejun
2015-07-15 12:43 ` George Dunlap
2015-07-15 13:23 ` Chen, Tiejun
2015-07-15 11:24 ` Jan Beulich
2015-07-15 11:38 ` George Dunlap
2015-07-15 11:27 ` Jan Beulich
2015-07-15 11:40 ` Chen, Tiejun
2015-07-15 8:32 ` Jan Beulich
2015-07-15 9:04 ` Chen, Tiejun
2015-07-15 12:57 ` Wei Liu
2015-07-15 13:40 ` George Dunlap
2015-07-15 14:00 ` Jan Beulich
2015-07-15 15:19 ` George Dunlap
2015-07-09 5:33 ` [v7][PATCH 07/16] hvmloader/e820: construct guest e820 table Tiejun Chen
2015-07-13 13:35 ` Jan Beulich
2015-07-14 5:22 ` Chen, Tiejun
2015-07-14 9:32 ` Jan Beulich
2015-07-14 10:22 ` Chen, Tiejun
2015-07-14 10:48 ` Jan Beulich
2015-07-15 16:00 ` George Dunlap
2015-07-16 1:58 ` Chen, Tiejun
2015-07-16 9:41 ` George Dunlap
2015-07-09 5:33 ` [v7][PATCH 08/16] tools/libxc: Expose new hypercall xc_reserved_device_memory_map Tiejun Chen
2015-07-09 5:34 ` [v7][PATCH 09/16] tools: extend xc_assign_device() to support rdm reservation policy Tiejun Chen
2015-07-09 5:34 ` [v7][PATCH 10/16] tools: introduce some new parameters to set rdm policy Tiejun Chen
2015-07-09 9:20 ` Wei Liu
2015-07-09 9:44 ` Chen, Tiejun
2015-07-09 10:37 ` Ian Jackson
2015-07-09 10:53 ` Chen, Tiejun
2015-07-09 18:02 ` Ian Jackson
2015-07-10 0:46 ` Chen, Tiejun
2015-07-09 5:34 ` [v7][PATCH 11/16] tools/libxl: detect and avoid conflicts with RDM Tiejun Chen
2015-07-09 9:11 ` Wei Liu
2015-07-09 9:41 ` Chen, Tiejun
2015-07-09 18:14 ` Ian Jackson
2015-07-10 3:19 ` Chen, Tiejun
2015-07-10 10:14 ` Ian Jackson
2015-07-13 9:19 ` Chen, Tiejun
2015-07-09 5:34 ` [v7][PATCH 12/16] tools: introduce a new parameter to set a predefined rdm boundary Tiejun Chen
2015-07-09 18:14 ` Ian Jackson
2015-07-09 5:34 ` [v7][PATCH 13/16] libxl: construct e820 map with RDM information for HVM guest Tiejun Chen
2015-07-09 18:17 ` Ian Jackson
2015-07-10 5:40 ` Chen, Tiejun
2015-07-10 9:18 ` Ian Campbell
2015-07-13 9:47 ` Chen, Tiejun
2015-07-13 10:15 ` Ian Campbell
2015-07-14 5:44 ` Chen, Tiejun
2015-07-14 7:42 ` Ian Campbell
2015-07-14 8:03 ` Chen, Tiejun
2015-07-10 10:15 ` Ian Jackson
2015-07-09 5:34 ` [v7][PATCH 14/16] xen/vtd: enable USB device assignment Tiejun Chen
2015-07-09 5:34 ` [v7][PATCH 15/16] xen/vtd: prevent from assign the device with shared rmrr Tiejun Chen
2015-07-13 13:41 ` Jan Beulich
2015-07-14 1:42 ` Chen, Tiejun
2015-07-14 9:19 ` Jan Beulich
2015-07-09 5:34 ` [v7][PATCH 16/16] tools: parse to enable new rdm policy parameters Tiejun Chen
2015-07-09 18:23 ` Ian Jackson
2015-07-10 6:05 ` Chen, Tiejun
2015-07-10 10:23 ` Ian Jackson
2015-07-13 9:31 ` Chen, Tiejun
2015-07-13 9:40 ` Ian Campbell
2015-07-13 9:55 ` Chen, Tiejun
2015-07-13 10:17 ` Ian Campbell
2015-07-13 17:08 ` Ian Jackson
2015-07-14 1:29 ` Chen, Tiejun
2015-07-10 14:50 ` [v7][PATCH 00/16] Fix RMRR George Dunlap
2015-07-10 14:56 ` Jan Beulich
2015-07-16 7:55 ` Jan Beulich
2015-07-16 8:03 ` Chen, Tiejun
2015-07-16 8:08 ` Jan Beulich
2015-07-16 8:13 ` Chen, Tiejun
2015-07-16 8:26 ` Jan Beulich
2015-07-16 9:27 ` George Dunlap
2015-07-16 9:44 ` Jan Beulich
2015-07-16 9:59 ` George Dunlap
2015-07-16 8:30 ` Ian Campbell
2015-07-16 8:46 ` Wei Liu
2015-07-16 9:45 ` Lars Kurth
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