Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | From | Reinette Chatre <> | Subject | [PATCH v5] x86/resctrl: Clear staged_config[] before and after it is used | Date | Tue, 17 Jan 2023 13:14:50 -0800 |
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From: Shawn Wang <shawnwang@linux.alibaba.com>
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> Tested-by: Reinette Chatre <reinette.chatre@intel.com> Cc: <stable@vger.kernel.org> --- Changes since v4: - Essentially a resubmit of v4, changes limited to commit tags. - v4: https://lore.kernel.org/lkml/20221209024436.22170-1-shawnwang@linux.alibaba.com/ - No changes to patch. - Only change in changelog is re-ordering of commit tags. - Add Reinette's Tested-by, but change the Reviewed-by to Signed-off-by because of the change in hands of this submission.
Changes since v3: - Update the commit message suggested by Reiniette Chatre. - Rename resctrl_staged_configs_clear() to rdt_staged_configs_clear(). - Move rdt_staged_configs_clear() to arch/x86/kernel/cpu/resctrl/internal.h.
Changes since v2: - Update the commit message suggested by Reiniette Chatre. - Make the clearing work more robust.
Changes since v1: - Move the clearing from schemata_list_destroy() to resctrl_arch_update_domains(). - Update the commit message suggested by Reiniette Chatre. - Add stable tag suggested by James Morse.
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 1df0e3262bca..bcdc679dad4e 100644 --- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c +++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c @@ -373,7 +373,6 @@ 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; @@ -402,10 +401,7 @@ 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, ":")); @@ -450,6 +446,7 @@ 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 5ebd28e6aa0c..f43eb7340ca5 100644 --- a/arch/x86/kernel/cpu/resctrl/internal.h +++ b/arch/x86/kernel/cpu/resctrl/internal.h @@ -527,5 +527,6 @@ 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 */ diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c index 5993da21d822..41e89fc49d77 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. @@ -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, -- 2.34.1
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