| 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
| ||
|
Message-ID: <41d7e325-c290-5bf5-5427-c3bf6e6e4f98@amd.com>
Date: Fri, 23 Aug 2024 17:04:07 -0500
From: "Moger, Babu" <bmoger@....com>
To: Reinette Chatre <reinette.chatre@...el.com>, babu.moger@....com,
corbet@....net, fenghua.yu@...el.com, tglx@...utronix.de, mingo@...hat.com,
bp@...en8.de, dave.hansen@...ux.intel.com
Cc: x86@...nel.org, hpa@...or.com, paulmck@...nel.org, rdunlap@...radead.org,
tj@...nel.org, peterz@...radead.org, yanjiewtw@...il.com,
kim.phillips@....com, lukas.bulwahn@...il.com, seanjc@...gle.com,
jmattson@...gle.com, leitao@...ian.org, jpoimboe@...nel.org,
rick.p.edgecombe@...el.com, kirill.shutemov@...ux.intel.com,
jithu.joseph@...el.com, kai.huang@...el.com, kan.liang@...ux.intel.com,
daniel.sneddon@...ux.intel.com, pbonzini@...hat.com, sandipan.das@....com,
ilpo.jarvinen@...ux.intel.com, peternewman@...gle.com,
maciej.wieczor-retman@...el.com, linux-doc@...r.kernel.org,
linux-kernel@...r.kernel.org, eranian@...gle.com, james.morse@....com
Subject: Re: [PATCH v6 22/22] x86/resctrl: Introduce interface to modify
assignment states of the groups
Hi Reinette,
On 8/23/2024 3:18 PM, Reinette Chatre wrote:
> Hi Babu,
>
> On 8/21/24 1:11 PM, Moger, Babu wrote:
>> On 8/16/24 17:33, Reinette Chatre wrote:
>>> On 8/6/24 3:00 PM, Babu Moger wrote:
>
> ...
>
>>>> +
>>>> +static int rdtgroup_str_to_mon_state(char *flag)
>>>> +{
>>>> + int i, mon_state = 0;
>>>> +
>>>> + for (i = 0; i < strlen(flag); i++) {
>>>> + switch (*(flag + i)) {
>>>> + case 't':
>>>> + mon_state |= ASSIGN_TOTAL;
>>>> + break;
>>>> + case 'l':
>>>> + mon_state |= ASSIGN_LOCAL;
>>>> + break;
>>>> + case '_':
>>>> + mon_state = ASSIGN_NONE;
>>>> + break;
>>>
>>> It looks like this supports flags like "_lt", treating it as assigning
>>> both local and total. I expect this should remove all flags instead?
>>
>> This is a cobination of flags.
>> "_lt" This will assign both local and total.
>> "lt_" This with remove both the flags.
>>
>> It seems alright to me. Do you want me to change the bahaviour here?
>
> This looks like undefined behavior to me. A request to set individual flags
> and also clear all flags looks like a contradiction to me.
Ok. Will address this in v7.
>
>>
>>
>>>
>>>> + default:
>>>> + break;
>>>> + }
>>>> + }
>>>> +
>>>> + return mon_state;
>>>> +}
>>>
>>> hmmm ... so you removed assigning mon_state to ASSIGN_NONE from default,
>>> but that did not change what this function returns since ASSIGN_NONE
>>> is 0
>>> and mon_state is initialized to 0. Unknown flags should cause error so
>>> that it is possible to add flags in the future. Above prevents us from
>>> ever adding new flags.
>>
>> May be I am missing something here. How about this?
>>
>> enum {
>> ASSIGN_NONE = 0,
>> ASSIGN_TOTAL,
>> ASSIGN_LOCAL,
>> ASSIGN_INVALID,
>> };
>>
>>
>> static int rdtgroup_str_to_mon_state(char *flag)
>> {
>> int i, mon_state = ASSIGN_NONE;
>>
>> for (i = 0; i < strlen(flag); i++) {
>> switch (*(flag + i)) {
>> case 't':
>> mon_state |= ASSIGN_TOTAL;
>> break;
>> case 'l':
>> mon_state |= ASSIGN_LOCAL;
>> break;
>> case '_':
>> mon_state = ASSIGN_NONE;
>> break;
>> default:
>> mon_state = ASSIGN_INVALID;
>> goto out_done;
>> }
>> }
>>
>> :out_done:
>> return mon_state;
>> }
>>
>> Then handle the ASSIGN_INVALID from the caller. Is that what you think?
>
> Why not return an error?
Sure.
>
>>
>>>
>>>> +
>>>> +static struct rdtgroup *rdtgroup_find_grp(enum rdt_group_type rtype,
>>>> char *p_grp, char *c_grp)
>>>
>>> rdtgroup_find_grp() -> rdtgroup_find_grp_by_name()?
>>>
>>>> +{
>>>> + struct rdtgroup *rdtg, *crg;
>>>> +
>>>> + if (rtype == RDTCTRL_GROUP && *p_grp == '\0') {
>>>> + return &rdtgroup_default;
>>>> + } else if (rtype == RDTCTRL_GROUP) {
>>>> + list_for_each_entry(rdtg, &rdt_all_groups, rdtgroup_list)
>>>> + if (!strcmp(p_grp, rdtg->kn->name))
>>>> + return rdtg;
>>>> + } else if (rtype == RDTMON_GROUP) {
>>>> + list_for_each_entry(rdtg, &rdt_all_groups, rdtgroup_list) {
>>>> + if (!strcmp(p_grp, rdtg->kn->name)) {
>>>> + list_for_each_entry(crg, &rdtg->mon.crdtgrp_list,
>>>> + mon.crdtgrp_list) {
>>>> + if (!strcmp(c_grp, crg->kn->name))
>>>> + return crg;
>>>> + }
>>>> + }
>>>> + }
>>>> + }
>>>> +
>>>> + return NULL;
>>>> +}
>>>> +
>>>> +static int rdtgroup_process_flags(struct rdt_resource *r,
>>>> + enum rdt_group_type rtype,
>>>> + char *p_grp, char *c_grp, char *tok)
>>>> +{
>>>> + int op, mon_state, assign_state, unassign_state;
>>>> + char *dom_str, *id_str, *op_str;
>>>> + struct rdt_mon_domain *d;
>>>> + struct rdtgroup *rdtgrp;
>>>> + unsigned long dom_id;
>>>> + int ret, found = 0;
>>>> +
>>>> + rdtgrp = rdtgroup_find_grp(rtype, p_grp, c_grp);
>>>> +
>>>> + if (!rdtgrp) {
>>>> + rdt_last_cmd_puts("Not a valid resctrl group\n");
>>>> + return -EINVAL;
>>>> + }
>>>> +
>>>> +next:
>>>> + if (!tok || tok[0] == '\0')
>>>> + return 0;
>>>> +
>>>> + /* Start processing the strings for each domain */
>>>> + dom_str = strim(strsep(&tok, ";"));
>>>> +
>>>> + op_str = strpbrk(dom_str, "=+-");
>>>> +
>>>> + if (op_str) {
>>>> + op = *op_str;
>>>> + } else {
>>>> + rdt_last_cmd_puts("Missing operation =, +, -, _ character\n");
>>>> + return -EINVAL;
>>>> + }
>>>> +
>>>> + id_str = strsep(&dom_str, "=+-");
>>>> +
>>>> + /* Check for domain id '*' which means all domains */
>>>> + if (id_str && *id_str == '*') {
>>>> + d = NULL;
>>>> + goto check_state;
>>>> + } else if (!id_str || kstrtoul(id_str, 10, &dom_id)) {
>>>> + rdt_last_cmd_puts("Missing domain id\n");
>>>> + return -EINVAL;
>>>> + }
>>>> +
>>>> + /* Verify if the dom_id is valid */
>>>> + list_for_each_entry(d, &r->mon_domains, hdr.list) {
>>>> + if (d->hdr.id == dom_id) {
>>>> + found = 1;
>>>> + break;
>>>> + }
>>>> + }
>>>> +
>>>> + if (!found) {
>>>> + rdt_last_cmd_printf("Invalid domain id %ld\n", dom_id);
>>>> + return -EINVAL;
>>>> + }
>>>> +
>>>> +check_state:
>>>> + mon_state = rdtgroup_str_to_mon_state(dom_str);
>>>
>>> Function should return error and exit here.
>>
>> No. This is case to skip checking for domain when '*' is passed to apply
>> assignment to all the domains.
>
> Using "*" for a domain still requires valid flags, no?
Yes. Flags will be process as usual.
>
> Reinette
>
--
- Babu Moger
Powered by blists - more mailing lists