The following commit has been merged into the x86/urgent branch of tip:

Commit-ID: 0424a7dfe9129b93f29b277511a60e87f052ac6b Gitweb: https://git.kernel.org/tip/0424a7dfe9129b93f29b277511a60e87f052ac6b Author: Shawn Wang shawnwang@linux.alibaba.com AuthorDate: Tue, 17 Jan 2023 13:14:50 -08:00 Committer: Dave Hansen dave.hansen@linux.intel.com CommitterDate: Wed, 15 Mar 2023 15:19:43 -07:00

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

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.1673988... --- arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 7 +----- arch/x86/kernel/cpu/resctrl/internal.h | 1 +- arch/x86/kernel/cpu/resctrl/rdtgroup.c | 25 ++++++++++++++++++---- 3 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c index eb07d44..b44c487 100644 --- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c +++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c @@ -368,7 +368,6 @@ 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; @@ -397,10 +396,7 @@ 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, ":")); @@ -445,6 +441,7 @@ 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; diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h index 8edecc5..85ceaf9 100644 --- a/arch/x86/kernel/cpu/resctrl/internal.h +++ b/arch/x86/kernel/cpu/resctrl/internal.h @@ -555,5 +555,6 @@ 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 __init mbm_config_rftype_init(const char *config); +void rdt_staged_configs_clear(void);

#endif /* _ASM_X86_RESCTRL_INTERNAL_H */ diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c index 884b6e9..6ad33f3 100644 --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c @@ -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. @@ -3107,7 +3120,9 @@ 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; @@ -3119,20 +3134,22 @@ 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,