From: "Jan Beulich" <JBeulich@suse.com>
To: Roger Pau Monne <roger.pau@citrix.com>
Cc: Anthony PERARD <anthony.perard@citrix.com>,
Ian Jackson <ian.jackson@eu.citrix.com>,
xen-devel@lists.xen.org, Wei Liu <wei.liu2@citrix.com>,
Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Subject: Re: [PATCH v4 06/14] xen: Move the hvm_start_info C representation from libxc to public/xen.h
Date: Mon, 21 Mar 2016 11:21:04 -0600 [thread overview]
Message-ID: <56F03B9002000078000DEFC3@prv-mh.provo.novell.com> (raw)
In-Reply-To: <alpine.OSX.2.20.1603211757181.24317@macbook-air-de-roger.local>
>>> On 21.03.16 at 18:04, <roger.pau@citrix.com> wrote:
> On Tue, 15 Mar 2016, Jan Beulich wrote:
>> >>> On 14.03.16 at 18:55, <anthony.perard@citrix.com> wrote:
>> > --- a/xen/include/public/xen.h
>> > +++ b/xen/include/public/xen.h
>> > @@ -841,6 +841,37 @@ typedef struct start_info start_info_t;
>> > */
>> > #define XEN_HVM_START_MAGIC_VALUE 0x336ec578
>> >
>> > +#if defined(__i386__) || defined(__x86_64__)
>> > +/* C representation of the x86/HVM start info layout.
>> > + *
>> > + * The canonical definition of this layout is abrove, this is just a way to
>> > + * represent the layout described there using C types.
>> > + *
>> > + * NB: the packed attribute is not really needed, but it helps us enforce
>> > + * the fact this this is just a representation, and it might indeed
>> > + * be required in the future if there are alignment changes.
>> > + */
>
> ^ Rationale on why the packed attribute was added.
Well, I admit to have overlooked this comment, but I don't see
how the packed attribute helps enforce anything. Hence, Anthony,
I think together with the attribute that part of the comment should
be removed.
> I would really like to avoid placing this in public headers, or else
> people will think this is the definition of the payload and will forget
> that this is just a C representation of it, but the definition is in a
> comment just above. I want to avoid the issues we have already seen by the
> usage of C structures as definitions of the placement of payloads in
> memory.
>
> If this really has to be there, please guard it with:
>
> #if defined(__XEN__) || defined(__XEN_TOOLS__)
>
> So only the Xen kernel/tools can use it.
And hvmloader can't. Not a good idea imo.
Jan
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next prev parent reply other threads:[~2016-03-21 17:21 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-14 17:55 [PATCH v4 00/14] Load BIOS via toolstack instead of been embedded in hvmloader Anthony PERARD
2016-03-14 17:55 ` [PATCH v4 01/14] libxc: Rework extra module initialisation Anthony PERARD
2016-03-16 0:06 ` Konrad Rzeszutek Wilk
2016-03-17 16:24 ` Anthony PERARD
2016-03-14 17:55 ` [PATCH v4 02/14] libxc: Prepare a start info structure for hvmloader Anthony PERARD
2016-03-16 0:18 ` Konrad Rzeszutek Wilk
2016-03-16 18:01 ` Boris Ostrovsky
2016-03-17 16:48 ` Anthony PERARD
2016-03-17 16:28 ` Anthony PERARD
2016-03-14 17:55 ` [PATCH v4 03/14] configure: #define SEABIOS_PATH and OVMF_PATH Anthony PERARD
2016-03-16 0:20 ` Konrad Rzeszutek Wilk
2016-04-08 13:38 ` Wei Liu
2016-03-14 17:55 ` [PATCH v4 04/14] firmware/makefile: install BIOS blob Anthony PERARD
2016-03-16 0:26 ` Konrad Rzeszutek Wilk
2016-03-16 8:54 ` Dario Faggioli
2016-03-16 8:56 ` Konrad Rzeszutek Wilk
2016-03-17 16:58 ` Anthony PERARD
2016-03-17 17:37 ` Doug Goldstein
2016-03-17 18:33 ` Anthony PERARD
2016-03-18 21:11 ` Jim Fehlig
2016-03-19 0:43 ` Doug Goldstein
2016-04-18 14:31 ` Doug Goldstein
2016-04-19 13:11 ` Stefano Stabellini
2016-03-14 17:55 ` [PATCH v4 05/14] libxl: Load guest BIOS from file Anthony PERARD
2016-03-16 0:53 ` Konrad Rzeszutek Wilk
2016-03-16 9:27 ` Dario Faggioli
2016-03-17 17:24 ` Anthony PERARD
2016-03-14 17:55 ` [PATCH v4 06/14] xen: Move the hvm_start_info C representation from libxc to public/xen.h Anthony PERARD
2016-03-15 8:09 ` Jan Beulich
2016-03-16 0:59 ` Konrad Rzeszutek Wilk
2016-03-16 1:00 ` Konrad Rzeszutek Wilk
2016-03-16 8:32 ` Jan Beulich
2016-03-21 17:04 ` Roger Pau Monné
2016-03-21 17:21 ` Jan Beulich [this message]
2016-03-14 17:55 ` [PATCH v4 07/14] hvmloader: Grab the hvm_start_info pointer Anthony PERARD
2016-03-16 1:07 ` Konrad Rzeszutek Wilk
2016-04-05 12:43 ` Jan Beulich
2016-03-14 17:55 ` [PATCH v4 08/14] hvmloader: Locate the BIOS blob Anthony PERARD
2016-03-16 1:14 ` Konrad Rzeszutek Wilk
2016-03-17 17:46 ` Anthony PERARD
2016-03-17 17:57 ` Konrad Rzeszutek Wilk
2016-03-18 7:34 ` Jan Beulich
2016-04-05 12:59 ` Jan Beulich
2016-04-05 14:05 ` Roger Pau Monné
2016-04-05 14:23 ` Jan Beulich
2016-04-07 15:10 ` Anthony PERARD
2016-04-07 15:30 ` Jan Beulich
2016-03-14 17:55 ` [PATCH v4 09/14] hvmloader: Check modules whereabouts in perform_tests Anthony PERARD
2016-03-16 1:23 ` Konrad Rzeszutek Wilk
2016-03-17 18:08 ` Anthony PERARD
2016-04-05 13:07 ` Jan Beulich
2016-03-14 17:55 ` [PATCH v4 10/14] hvmloader: Load SeaBIOS from hvm_start_info modules Anthony PERARD
2016-03-16 1:27 ` Konrad Rzeszutek Wilk
2016-03-16 1:27 ` Konrad Rzeszutek Wilk
2016-04-05 13:11 ` Jan Beulich
2016-03-14 17:55 ` [PATCH v4 11/14] hvmloader: Load OVMF from modules Anthony PERARD
2016-03-16 1:36 ` Konrad Rzeszutek Wilk
2016-04-05 13:16 ` Jan Beulich
2016-03-14 17:55 ` [PATCH v4 12/14] hvmloader: Specific bios_load function required Anthony PERARD
2016-03-16 1:38 ` Konrad Rzeszutek Wilk
2016-03-17 18:25 ` Anthony PERARD
2016-03-14 17:55 ` [PATCH v4 13/14] hvmloader: Always build-in SeaBIOS and OVMF loader Anthony PERARD
2016-03-14 17:55 ` [PATCH v4 14/14] configure: do not depend on SEABIOS_PATH or OVMF_PATH Anthony PERARD
2016-03-16 1:40 ` Konrad Rzeszutek Wilk
2016-04-08 13:38 ` Wei Liu
2016-03-24 17:55 ` [PATCH v4 00/14] Load BIOS via toolstack instead of been embedded in hvmloader Jim Fehlig
2016-03-30 17:22 ` Jim Fehlig
2016-03-31 7:20 ` Jan Beulich
[not found] ` <56FCEBCD02000078000E19BF@suse.com>
2016-03-31 14:36 ` Jim Fehlig
2016-03-31 16:49 ` George Dunlap
2016-04-01 9:12 ` George Dunlap
2016-04-01 14:24 ` Konrad Rzeszutek Wilk
2016-04-01 20:06 ` Jim Fehlig
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