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x86/resctrl: Clear staged_config[] before and after it is used

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commit 0424a7dfe9129b93f29b277511a60e87f052ac6b upstream.

As a temporary storage, staged_config[] in rdt_domain should be cleared
before and after it is used. The stale value in staged_config[] could
cause an MSR access error.

Here is a reproducer on a system with 16 usable CLOSIDs for a 15-way L3
Cache (MBA should be disabled if the number of CLOSIDs for MB is less than
16.) :
	mount -t resctrl resctrl -o cdp /sys/fs/resctrl
	mkdir /sys/fs/resctrl/p{1..7}
	umount /sys/fs/resctrl/
	mount -t resctrl resctrl /sys/fs/resctrl
	mkdir /sys/fs/resctrl/p{1..8}

An error occurs when creating resource group named p8:
    unchecked MSR access error: WRMSR to 0xca0 (tried to write 0x00000000000007ff) at rIP: 0xffffffff82249142 (cat_wrmsr+0x32/0x60)
    Call Trace:
     <IRQ>
     __flush_smp_call_function_queue+0x11d/0x170
     __sysvec_call_function+0x24/0xd0
     sysvec_call_function+0x89/0xc0
     </IRQ>
     <TASK>
     asm_sysvec_call_function+0x16/0x20

When creating a new resource control group, hardware will be configured
by the following process:
    rdtgroup_mkdir()
      rdtgroup_mkdir_ctrl_mon()
        rdtgroup_init_alloc()
          resctrl_arch_update_domains()

resctrl_arch_update_domains() iterates and updates all resctrl_conf_type
whose have_new_ctrl is true. Since staged_config[] holds the same values as
when CDP was enabled, it will continue to update the CDP_CODE and CDP_DATA
configurations. When group p8 is created, get_config_index() called in
resctrl_arch_update_domains() will return 16 and 17 as the CLOSIDs for
CDP_CODE and CDP_DATA, which will be translated to an invalid register -
0xca0 in this scenario.

Fix it by clearing staged_config[] before and after it is used.

[reinette: re-order commit tags]

Fixes: 75408e43509e ("x86/resctrl: Allow different CODE/DATA configurations to be staged")
Suggested-by: Xin Hao <xhao@linux.alibaba.com>
Signed-off-by: Shawn Wang <shawnwang@linux.alibaba.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Tested-by: Reinette Chatre <reinette.chatre@intel.com>
Cc:stable@vger.kernel.org
Link: https://lore.kernel.org/all/2fad13f49fbe89687fc40e9a5a61f23a28d1507a.1673988935.git.reinette.chatre%40intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Shawn Wang 2023-01-17 13:14:50 -08:00 committed by Greg Kroah-Hartman
parent 701d3da213
commit 3fc5941ecc
3 changed files with 24 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
arch/x86/kernel/cpu/resctrl/ctrlmondata.c
View File

@ -374,7 +374,6 @@ ssize_t rdtgroup_schemata_write(struct kernfs_open_file *of,
{
struct resctrl_schema *s;
struct rdtgroup *rdtgrp;
struct rdt_domain *dom;
struct rdt_resource *r;
char *tok, *resname;
int ret = 0;
@ -403,10 +402,7 @@ ssize_t rdtgroup_schemata_write(struct kernfs_open_file *of,
goto out;
}
list_for_each_entry(s, &resctrl_schema_all, list) {
list_for_each_entry(dom, &s->res->domains, list)
memset(dom->staged_config, 0, sizeof(dom->staged_config));
}
rdt_staged_configs_clear();
while ((tok = strsep(&buf, "\n")) != NULL) {
resname = strim(strsep(&tok, ":"));
@ -451,6 +447,7 @@ ssize_t rdtgroup_schemata_write(struct kernfs_open_file *of,
}
out:
rdt_staged_configs_clear();
rdtgroup_kn_unlock(of->kn);
cpus_read_unlock();
return ret ?: nbytes;

1
arch/x86/kernel/cpu/resctrl/internal.h
View File

@ -537,5 +537,6 @@ bool has_busy_rmid(struct rdt_resource *r, struct rdt_domain *d);
void __check_limbo(struct rdt_domain *d, bool force_free);
void rdt_domain_reconfigure_cdp(struct rdt_resource *r);
void __init thread_throttle_mode_init(void);
void rdt_staged_configs_clear(void);
#endif /* _ASM_X86_RESCTRL_INTERNAL_H */

25
arch/x86/kernel/cpu/resctrl/rdtgroup.c
View File

@ -78,6 +78,19 @@ void rdt_last_cmd_printf(const char *fmt, ...)
va_end(ap);
}
void rdt_staged_configs_clear(void)
{
struct rdt_resource *r;
struct rdt_domain *dom;
lockdep_assert_held(&rdtgroup_mutex);
for_each_alloc_capable_rdt_resource(r) {
list_for_each_entry(dom, &r->domains, list)
memset(dom->staged_config, 0, sizeof(dom->staged_config));
}
}
/*
* Trivial allocator for CLOSIDs. Since h/w only supports a small number,
* we can keep a bitmap of free CLOSIDs in a single integer.
@ -2851,7 +2864,9 @@ static int rdtgroup_init_alloc(struct rdtgroup *rdtgrp)
{
struct resctrl_schema *s;
struct rdt_resource *r;
int ret;
int ret = 0;
rdt_staged_configs_clear();
list_for_each_entry(s, &resctrl_schema_all, list) {
r = s->res;
@ -2862,20 +2877,22 @@ static int rdtgroup_init_alloc(struct rdtgroup *rdtgrp)
} else {
ret = rdtgroup_init_cat(s, rdtgrp->closid);
if (ret < 0)
return ret;
goto out;
}
ret = resctrl_arch_update_domains(r, rdtgrp->closid);
if (ret < 0) {
rdt_last_cmd_puts("Failed to initialize allocations\n");
return ret;
goto out;
}
}
rdtgrp->mode = RDT_MODE_SHAREABLE;
return 0;
out:
rdt_staged_configs_clear();
return ret;
}
static int mkdir_rdt_prepare(struct kernfs_node *parent_kn,