linux-kernel - Re: [PATCH v7 09/10] fs/resctrl: Modify rdt_parse

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <5bfb400a-948c-40d1-b509-affcc22341f0@amd.com>
Date: Mon, 4 Aug 2025 14:32:08 -0500
From: "Moger, Babu" <babu.moger@....com>
To: Reinette Chatre <reinette.chatre@...el.com>, corbet@....net,
 tony.luck@...el.com, Dave.Martin@....com, james.morse@....com,
 tglx@...utronix.de, mingo@...hat.com, bp@...en8.de,
 dave.hansen@...ux.intel.com
Cc: x86@...nel.org, hpa@...or.com, akpm@...ux-foundation.org,
 paulmck@...nel.org, rostedt@...dmis.org, Neeraj.Upadhyay@....com,
 david@...hat.com, arnd@...db.de, fvdl@...gle.com, seanjc@...gle.com,
 thomas.lendacky@....com, pawan.kumar.gupta@...ux.intel.com,
 yosry.ahmed@...ux.dev, sohil.mehta@...el.com, xin@...or.com,
 kai.huang@...el.com, xiaoyao.li@...el.com, peterz@...radead.org,
 me@...aill.net, mario.limonciello@....com, xin3.li@...el.com,
 ebiggers@...gle.com, ak@...ux.intel.com, chang.seok.bae@...el.com,
 andrew.cooper3@...rix.com, perry.yuan@....com, linux-doc@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v7 09/10] fs/resctrl: Modify rdt_parse_data to pass mode
 and CLOSID

Hi Reinette,

On 7/21/25 22:30, Reinette Chatre wrote:
> Hi Babu,
> 
> On 7/10/25 10:16 AM, Babu Moger wrote:
>> The functions parse_cbm() and parse_bw() require mode and CLOSID to
> 
> No need to say "function" when using (). Also, drop parse_bw(), since it
> does not validate CBMs.

Sure.
> 
>> validate the Capacity Bit Mask (CBM). It is passed through struct
> 
> "passed through" -> "passed via"?
> 

Sure.

>> rdtgroup in rdt_parse_data.
> 
> "rdt_parse_data" -> "struct rdt_parse_data"
> 

Sure.

>>
>> This can be simplified by passing the mode and closid directly, instead of
> 
> closid -> CLOSID
> 
Sure,

>> through the rdtgroup struct. Doing so also facilitates calling parse_cbm()
>> to verify the CBM within the io_alloc feature, since io_alloc does not
>> have rdtgroup context.
> 
> Above notes that "simplification" is the primary motivation but I do not think
> this change qualifies as a "simplification". How about second paragraph changed
> to something like:
> 
> 	The io_alloc feature also uses CBMs to indicate which portions of
> 	cache are allocated for I/O traffic. The CBMs are provided by
> 	user space and need to be validated the same as CBMs provided for
> 	general (CPU) cache allocation. parse_cbm() cannot be used as-is
> 	since io_alloc does not have rdtgroup context.
> 
> 	Pass the mode and CLOSID directly to parse_cbm() via struct rdt_parse_data
> 	instead of through the rdtgroup struct to facilitate calling parse_cbm() to
> 	verify the CBM of the io_alloc feature.
> 
> (please feel free to improve)
> 

Looks good.

>>
>> Signed-off-by: Babu Moger <babu.moger@....com>
>> ---
> 
> 
> 
>> ---
>>  fs/resctrl/ctrlmondata.c | 29 +++++++++++++----------------
>>  fs/resctrl/internal.h    |  6 ++++++
>>  2 files changed, 19 insertions(+), 16 deletions(-)
>>
>> diff --git a/fs/resctrl/ctrlmondata.c b/fs/resctrl/ctrlmondata.c
>> index e78828b0408a..5c16557fb7a8 100644
>> --- a/fs/resctrl/ctrlmondata.c
>> +++ b/fs/resctrl/ctrlmondata.c
>> @@ -23,11 +23,6 @@
>>  
>>  #include "internal.h"
>>  
>> -struct rdt_parse_data {
>> -	struct rdtgroup		*rdtgrp;
>> -	char			*buf;
>> -};
>> -
> 
> This patch is only about replacing rdtgroup with mode and CLOSID, there is no
> motivation for relocating the structure declaration. This looks to be a change
> needed by following patch but is another change that becomes unnecessary if
> the io_alloc code, specifically resctrl_io_alloc_cbm_write() and
> resctrl_io_alloc_parse_line() from next patch, are moved to ctrlmondata.c.
> 

Yes. Not required to move now.

> ...
> 
>> @@ -171,7 +167,7 @@ static int parse_cbm(struct rdt_parse_data *data, struct resctrl_schema *s,
>>  	 * Cannot set up more than one pseudo-locked region in a cache
>>  	 * hierarchy.
>>  	 */
>> -	if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP &&
>> +	if (mode == RDT_MODE_PSEUDO_LOCKSETUP &&
>>  	    rdtgroup_pseudo_locked_in_hierarchy(d)) {
>>  		rdt_last_cmd_puts("Pseudo-locked region in hierarchy\n");
>>  		return -EINVAL;
>> @@ -180,9 +176,9 @@ static int parse_cbm(struct rdt_parse_data *data, struct resctrl_schema *s,
>>  	if (!cbm_validate(data->buf, &cbm_val, r))
>>  		return -EINVAL;
>>  
>> -	if ((rdtgrp->mode == RDT_MODE_EXCLUSIVE ||
>> -	     rdtgrp->mode == RDT_MODE_SHAREABLE) &&
>> -	    rdtgroup_cbm_overlaps_pseudo_locked(d, cbm_val)) {
>> +	if ((mode == RDT_MODE_EXCLUSIVE ||
>> +	     mode == RDT_MODE_SHAREABLE) &&
>> +	     rdtgroup_cbm_overlaps_pseudo_locked(d, cbm_val)) {
> 
> Please fix alignment.

Sure.

> 
>>  		rdt_last_cmd_puts("CBM overlaps with pseudo-locked region\n");
>>  		return -EINVAL;
>>  	}
> 
> Reinette
> 

-- 
Thanks
Babu Moger