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From: "Jürgen Groß" <jgross@suse.com>
To: Jan Beulich <jbeulich@suse.com>, Julien Grall <julien@xen.org>
Cc: "Stefano Stabellini" <sstabellini@kernel.org>,
	"Wei Liu" <wl@xen.org>,
	"Konrad Rzeszutek Wilk" <konrad.wilk@oracle.com>,
	"Andrew Cooper" <andrew.cooper3@citrix.com>,
	"Ian Jackson" <ian.jackson@eu.citrix.com>,
	"George Dunlap" <george.dunlap@citrix.com>,
	xen-devel@lists.xenproject.org,
	"Roger Pau Monné" <roger.pau@citrix.com>
Subject: Re: [Xen-devel] [PATCH v6 01/12] xen: allow only sizeof(bool) variables for boolean_param()
Date: Mon, 9 Mar 2020 14:01:35 +0100	[thread overview]
Message-ID: <f101fc47-329c-e704-86cd-0411b6a15f99@suse.com> (raw)
In-Reply-To: <471c2f88-2ac2-823d-546f-6fc817e34ec8@suse.com>

On 09.03.20 12:55, Jan Beulich wrote:
> On 09.03.2020 12:43, Julien Grall wrote:
>> On 26/02/2020 12:46, Juergen Gross wrote:
>>> @@ -46,7 +48,8 @@ extern const struct kernel_param __param_start[], __param_end[];
>>>        __kparam __setup_##_var = \
>>>            { .name = __setup_str_##_var, \
>>>              .type = OPT_BOOL, \
>>> -          .len = sizeof(_var), \
>>> +          .len = sizeof(_var) + \
>>> +                 BUILD_BUG_ON_ZERO(sizeof(_var) != sizeof(bool)), \
>>
>>   From my understanding, sizeof(bool) is not necessarily 1 (it can be
>> greater). While this is fine to use it in Xen, I think we want it to
>> always be one when exposed in the hypfs.
> 
> I don't think so: We want variable of type 'bool' to be updated
> consistently (i.e. by a write to the full variable). Hence I
> think sizeof(bool) is correct here. I can see though that the
> hypercall interface then gains a dependency on the hypervisor's
> representation of 'bool', but I think such ought to be taken
> care of in the function carrying out the write, not in the
> macro here.

So you think I should special case bool entries when returning the
size information? Or do you think its fine to have the hypervisor's
size reported and let the lib do the size handling correctly?


Juergen

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  reply	other threads:[~2020-03-09 13:02 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-26 12:46 [Xen-devel] [PATCH v6 00/12] Add hypervisor sysfs-like support Juergen Gross
2020-02-26 12:46 ` [Xen-devel] [PATCH v6 01/12] xen: allow only sizeof(bool) variables for boolean_param() Juergen Gross
2020-03-03 16:40   ` Jan Beulich
2020-03-09 11:43   ` Julien Grall
2020-03-09 11:55     ` Jan Beulich
2020-03-09 13:01       ` Jürgen Groß [this message]
2020-03-09 13:06         ` Jan Beulich
2020-03-09 14:06           ` Jürgen Groß
2020-02-26 12:46 ` [Xen-devel] [PATCH v6 02/12] xen: add a generic way to include binary files as variables Juergen Gross
2020-02-26 12:46 ` [Xen-devel] [PATCH v6 03/12] docs: add feature document for Xen hypervisor sysfs-like support Juergen Gross
2020-03-09 11:48   ` Julien Grall
2020-03-25 14:05     ` Jürgen Groß
2020-02-26 12:46 ` [Xen-devel] [PATCH v6 04/12] xen: add basic hypervisor filesystem support Juergen Gross
2020-03-03 16:59   ` Jan Beulich
2020-03-04 12:00     ` Jürgen Groß
2020-03-04 13:03       ` Jan Beulich
2020-03-04 14:39         ` Jürgen Groß
2020-03-04 15:07           ` Jan Beulich
2020-03-04 15:14             ` Jürgen Groß
2020-03-04 15:21               ` Jan Beulich
2020-03-06  6:06                 ` Jürgen Groß
2020-03-06  8:19                   ` Jan Beulich
2020-02-26 12:46 ` [Xen-devel] [PATCH v6 05/12] libs: add libxenhypfs Juergen Gross
2020-02-26 12:46 ` [Xen-devel] [PATCH v6 06/12] tools: add xenfs tool Juergen Gross
2020-02-26 12:47 ` [Xen-devel] [PATCH v6 07/12] xen: provide version information in hypfs Juergen Gross
2020-02-26 12:47 ` [Xen-devel] [PATCH v6 08/12] xen: add /buildinfo/config entry to hypervisor filesystem Juergen Gross
2020-03-04 10:49   ` Jan Beulich
2020-03-04 12:06     ` Jürgen Groß
2020-03-04 13:04       ` Jan Beulich
2020-02-26 12:47 ` [Xen-devel] [PATCH v6 09/12] xen: add runtime parameter access support to hypfs Juergen Gross
2020-03-04 11:32   ` Jan Beulich
2020-03-04 15:07     ` Jürgen Groß
2020-03-04 15:19       ` Jan Beulich
2020-03-04 16:31         ` Jürgen Groß
2020-03-04 16:56           ` Jan Beulich
2020-03-05  6:01             ` Jürgen Groß
2020-03-05  8:26               ` Jan Beulich
2020-03-06  6:42                 ` Jürgen Groß
2020-03-06  8:20                   ` Jan Beulich
2020-03-06  8:47                     ` Jürgen Groß
2020-03-06  9:04                       ` Jan Beulich
2020-03-06  9:20                         ` Jürgen Groß
2020-03-06  9:22                           ` Jan Beulich
2020-03-06  9:27                             ` Jürgen Groß
2020-03-23 10:38   ` Julien Grall
2020-02-26 12:47 ` [Xen-devel] [PATCH v6 10/12] tools/libxl: use libxenhypfs for setting xen runtime parameters Juergen Gross
2020-02-26 12:47 ` [Xen-devel] [PATCH v6 11/12] tools/libxc: remove xc_set_parameters() Juergen Gross
2020-02-26 12:47 ` [Xen-devel] [PATCH v6 12/12] xen: remove XEN_SYSCTL_set_parameter support Juergen Gross
2020-03-04 11:45   ` Jan Beulich
2020-03-04 14:40     ` Jürgen Groß

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