xen-devel.lists.xenproject.org archive mirror
 help / color / mirror / Atom feed
From: Juergen Gross <jgross@suse.com>
To: Stefano Stabellini <sstabellini@kernel.org>
Cc: xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH 1/3] xen: check required Xen features
Date: Thu, 22 Apr 2021 17:32:32 +0200	[thread overview]
Message-ID: <6f3a782b-0d1d-e86e-998b-bc3b46e1f4c3@suse.com> (raw)
In-Reply-To: <alpine.DEB.2.21.2104220823160.5018@sstabellini-ThinkPad-T480s>


[-- Attachment #1.1.1: Type: text/plain, Size: 1746 bytes --]

On 22.04.21 17:26, Stefano Stabellini wrote:
> On Thu, 22 Apr 2021, Juergen Gross wrote:
>> Linux kernel is not supported to run on Xen versions older than 4.0.
>>
>> Add tests for required Xen features always being present in Xen 4.0
>> and newer.
>>
>> Signed-off-by: Juergen Gross <jgross@suse.com>
>> ---
>>   drivers/xen/features.c | 18 ++++++++++++++++++
>>   1 file changed, 18 insertions(+)
>>
>> diff --git a/drivers/xen/features.c b/drivers/xen/features.c
>> index 25c053b09605..60503299c9bc 100644
>> --- a/drivers/xen/features.c
>> +++ b/drivers/xen/features.c
>> @@ -9,13 +9,26 @@
>>   #include <linux/types.h>
>>   #include <linux/cache.h>
>>   #include <linux/export.h>
>> +#include <linux/printk.h>
>>   
>>   #include <asm/xen/hypercall.h>
>>   
>> +#include <xen/xen.h>
>>   #include <xen/interface/xen.h>
>>   #include <xen/interface/version.h>
>>   #include <xen/features.h>
>>   
>> +/*
>> + * Linux kernel expects at least Xen 4.0.
>> + *
>> + * Assume some features to be available for that reason (depending on guest
>> + * mode, of course).
>> + */
>> +#define chk_feature(f) {						\
>> +		if (!xen_feature(f))					\
>> +			pr_err("Xen: feature %s not available!\n", #f);	\
>> +	}
> 
> I think this could be done as a static inline function in
> include/xen/features.h. That way it would be available everywhere. Also,
> static inlines are better than macro when it is possible to use them in
> terms of code safety.

It is a macro in order to have only one parameter.

And being a local macro is rendering the code safety reasoning moot.

Additionally I don't want this testing to be scattered all over the
code base. It should be done in one place only.


Juergen

[-- Attachment #1.1.2: OpenPGP_0xB0DE9DD628BF132F.asc --]
[-- Type: application/pgp-keys, Size: 3135 bytes --]

[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 495 bytes --]

  reply	other threads:[~2021-04-22 15:33 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-22 15:10 [PATCH 0/3] xen: remove some checks for always present " Juergen Gross
2021-04-22 15:10 ` [PATCH 1/3] xen: check required " Juergen Gross
2021-04-22 15:26   ` Stefano Stabellini
2021-04-22 15:32     ` Juergen Gross [this message]
2021-05-10 12:11   ` Boris Ostrovsky
2021-05-10 13:21     ` Juergen Gross
2021-04-22 15:10 ` [PATCH 2/3] xen: assume XENFEAT_mmu_pt_update_preserve_ad being set for pv guests Juergen Gross
2021-04-22 15:10 ` [PATCH 3/3] xen: assume XENFEAT_gnttab_map_avail_bits " Juergen Gross
2021-04-22 15:16 ` [PATCH 0/3] xen: remove some checks for always present Xen features Jan Beulich
2021-04-22 15:17   ` Juergen Gross
2021-04-22 15:23     ` Jan Beulich
2021-04-22 15:28       ` Juergen Gross
2021-04-22 15:42         ` Jan Beulich
2021-04-22 15:49           ` Juergen Gross
2021-04-22 15:51           ` Andrew Cooper
2021-05-10  7:34 ` Juergen Gross
2021-05-10 11:31   ` Peter Zijlstra

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=6f3a782b-0d1d-e86e-998b-bc3b46e1f4c3@suse.com \
    --to=jgross@suse.com \
    --cc=boris.ostrovsky@oracle.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=peterz@infradead.org \
    --cc=sstabellini@kernel.org \
    --cc=xen-devel@lists.xenproject.org \
    --subject='Re: [PATCH 1/3] xen: check required Xen features' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).