Privilege Level Zero Association (PLZA) is configured by writing to MSR_IA32_PQR_PLZA_ASSOC. PLZA is disabled by default on all logical processors in the QOS Domain. System software must follow the following sequence. 1. Set the closid, closid_en, rmid and rmid_en fields of MSR_IA32_PQR_PLZA_ASSOC to the desired configuration on all logical processors in the QOS Domain. 2. Set MSR_IA32_PQR_PLZA_ASSOC[PLZA_EN]=1 for all logical processors in the QOS domain where PLZA should be enabled. MSR_IA32_PQR_PLZA_ASSOC[PLZA_EN] may have a different value on every logical processor in the QOS domain. The system software should perform this as a read-modify-write to avoid changing the value of closid_en, closid, rmid_en, and rmid fields of MSR_IA32_PQR_PLZA_ASSOC. Signed-off-by: Babu Moger --- v2: - Updated the commit message to include the sequence of steps to enable PLZA. Added mode code comments for clarity. Added kmode to functin names to be generic. --- arch/x86/include/asm/resctrl.h | 19 ++++++ arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 77 +++++++++++++++++++++++ include/linux/resctrl.h | 30 +++++++++ 3 files changed, 126 insertions(+) diff --git a/arch/x86/include/asm/resctrl.h b/arch/x86/include/asm/resctrl.h index e0a992abaeb4..167be18983c1 100644 --- a/arch/x86/include/asm/resctrl.h +++ b/arch/x86/include/asm/resctrl.h @@ -186,6 +186,25 @@ static inline bool resctrl_arch_match_rmid(struct task_struct *tsk, u32 ignored, return READ_ONCE(tsk->rmid) == rmid; } +/** + * resctrl_arch_set_cpu_kmode() - Set per-CPU kernel mode state for PLZA programming + * @cpu: Logical CPU to update. + * @closid: CLOSID to use for kernel work on this CPU when kmode is enabled. + * @rmid: RMID to use for kernel work on this CPU when kmode is enabled. + * @enable: 1 to enable PLZA on this CPU; 0 to leave disabled. Stored in default_kmode. + * + * Stores the given CLOSID, RMID, and enable value in per-CPU state (kmode_closid, + * kmode_rmid, default_kmode). The actual MSR_IA32_PQR_PLZA_ASSOC write is done + * separately (e.g. via on_each_cpu_mask) so that closid/rmid are set on all CPUs + * in the domain before PLZA_EN is set, per the PLZA programming sequence. + */ +static inline void resctrl_arch_set_cpu_kmode(int cpu, u32 closid, u32 rmid, u32 enable) +{ + WRITE_ONCE(per_cpu(pqr_state.default_kmode, cpu), enable); + WRITE_ONCE(per_cpu(pqr_state.kmode_closid, cpu), closid); + WRITE_ONCE(per_cpu(pqr_state.kmode_rmid, cpu), rmid); +} + static inline void resctrl_arch_sched_in(struct task_struct *tsk) { if (static_branch_likely(&rdt_enable_key)) diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c index b20e705606b8..b5dfe30aca26 100644 --- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c +++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c @@ -131,3 +131,80 @@ int resctrl_arch_io_alloc_enable(struct rdt_resource *r, bool enable) return 0; } + +/* + * IPI callback: write MSR_IA32_PQR_PLZA_ASSOC on this CPU (AMD PLZA). + */ +static void resctrl_kmode_set_one_amd(void *arg) +{ + union qos_pqr_plza_assoc *plza = arg; + + wrmsrl(MSR_IA32_PQR_PLZA_ASSOC, plza->full); +} + +/** + * resctrl_arch_configure_kmode() - x86/AMD: program PLZA per control domain + * + * For each control domain, first sets per-CPU state (closid, rmid, enable=0) + * on all CPUs in the domain, then writes MSR_IA32_PQR_PLZA_ASSOC on each CPU + * so that closid/closid_en (and optionally rmid/rmid_en) are programmed + * before PLZA_EN is set, per the PLZA programming sequence. + */ +void resctrl_arch_configure_kmode(struct rdt_resource *r, struct resctrl_kmode_cfg *kcfg, + u32 closid, u32 rmid) +{ + union qos_pqr_plza_assoc plza = { 0 }; + struct rdt_ctrl_domain *d; + int cpu; + + if (kcfg->kmode_cur & INHERIT_CTRL_AND_MON) + return; + + if (kcfg->kmode_cur & GLOBAL_ASSIGN_CTRL_ASSIGN_MON) { + plza.split.rmid = rmid; + plza.split.rmid_en = 1; + } + plza.split.closid = closid; + plza.split.closid_en = 1; + + list_for_each_entry(d, &r->ctrl_domains, hdr.list) { + for_each_cpu(cpu, &d->hdr.cpu_mask) + resctrl_arch_set_cpu_kmode(cpu, closid, rmid, 0); + on_each_cpu_mask(&d->hdr.cpu_mask, resctrl_kmode_set_one_amd, &plza, 1); + } +} + +/** + * resctrl_arch_set_kmode() - x86/AMD: set PLZA enable/disable on a set of CPUs + * @cpu_mask: CPUs to update (e.g. a control domain's cpu_mask). + * @kcfg: Current kernel mode configuration. + * @closid: CLOSID to use for kernel work when a global assign mode is active. + * @rmid: RMID to use for kernel work when GLOBAL_ASSIGN_CTRL_ASSIGN_MON is active. + * @enable: True to set MSR_IA32_PQR_PLZA_ASSOC.PLZA_EN; false to clear it. + * + * Writes MSR_IA32_PQR_PLZA_ASSOC on each CPU in @cpu_mask (via IPI) and updates + * per-CPU state. No-op when kmode_cur is INHERIT_CTRL_AND_MON. Call after + * resctrl_arch_configure_kmode() so that closid/rmid are programmed before + * PLZA_EN is set. + */ +void resctrl_arch_set_kmode(cpumask_var_t cpu_mask, struct resctrl_kmode_cfg *kcfg, + u32 closid, u32 rmid, bool enable) +{ + int cpu; + union qos_pqr_plza_assoc plza = { 0 }; + + if (kcfg->kmode_cur & INHERIT_CTRL_AND_MON) + return; + + if (kcfg->kmode_cur & GLOBAL_ASSIGN_CTRL_ASSIGN_MON) { + plza.split.rmid = rmid; + plza.split.rmid_en = 1; + } + plza.split.closid = closid; + plza.split.closid_en = 1; + plza.split.plza_en = enable; + + on_each_cpu_mask(cpu_mask, resctrl_kmode_set_one_amd, &plza, 1); + for_each_cpu(cpu, cpu_mask) + resctrl_arch_set_cpu_kmode(cpu, closid, rmid, enable); +} diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h index 2c36d1ac392f..3f3e8c1e549b 100644 --- a/include/linux/resctrl.h +++ b/include/linux/resctrl.h @@ -709,6 +709,36 @@ bool resctrl_arch_get_io_alloc_enabled(struct rdt_resource *r); */ void resctrl_arch_get_kmode_cfg(struct resctrl_kmode_cfg *kcfg); +/** + * resctrl_arch_configure_kmode() - Program kernel mode (e.g. PLZA) for all domains + * @r: The resctrl resource (scope for control domains). + * @kcfg: Current kernel mode configuration. + * @closid: CLOSID to use for kernel work when a global assign mode is active. + * @rmid: RMID to use for kernel work when GLOBAL_ASSIGN_CTRL_ASSIGN_MON is active. + * + * Programs each control domain so that kernel work uses the given CLOSID/RMID + * per the active kernel mode (e.g. MSR_IA32_PQR_PLZA_ASSOC on x86). No-op when + * kmode_cur is INHERIT_CTRL_AND_MON. May be called from any CPU. + */ +void resctrl_arch_configure_kmode(struct rdt_resource *r, struct resctrl_kmode_cfg *kcfg, + u32 closid, u32 rmid); + +/** + * resctrl_arch_set_kmode() - Set kernel mode (e.g. PLZA) on a set of CPUs + * @cpu_mask: CPUs to update (e.g. a control domain's cpu_mask). + * @kcfg: Current kernel mode configuration. + * @closid: CLOSID to use for kernel work when a global assign mode is active. + * @rmid: RMID to use for kernel work when GLOBAL_ASSIGN_CTRL_ASSIGN_MON is active. + * @enable: True to set MSR_IA32_PQR_PLZA_ASSOC.PLZA_EN on the CPUs; false to clear it. + * + * Writes MSR_IA32_PQR_PLZA_ASSOC on each CPU in @cpu_mask and updates per-CPU + * state. No-op when kmode_cur is INHERIT_CTRL_AND_MON. Call after + * resctrl_arch_configure_kmode() so that closid/rmid are programmed before + * PLZA_EN is set. May be called from any CPU. + */ +void resctrl_arch_set_kmode(cpumask_var_t cpu_mask, struct resctrl_kmode_cfg *kcfg, + u32 closid, u32 rmid, bool enable); + extern unsigned int resctrl_rmid_realloc_threshold; extern unsigned int resctrl_rmid_realloc_limit; -- 2.43.0