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(repetition) > > On AMD systems, "io_alloc" feature is backed by L3 Smart Data Cache > Injection Allocation Enforcement (SDCIAE). Change SDCIAE state by setting > (to enable) or clearing (to disable) bit 1 of MSR L3_QOS_EXT_CFG on all Did you notice Boris's touchup on ABMC "x86/resctrl: Add data structures and definitions for ABMC assignment"? This should be MSR_IA32_L3_QOS_EXT_CFG (also needed in patch self, more below) > logical processors within the cache domain. > > Introduce architecture-specific call to enable and disable the feature. > > The SDCIAE feature details are documented in APM [1] available from [2]. > [1] AMD64 Architecture Programmer's Manual Volume 2: System Programming > Publication # 24593 Revision 3.41 section 19.4.7 L3 Smart Data Cache > Injection Allocation Enforcement (SDCIAE) (same comment as patch #1) Changelog that aims to address feeback received in ABMC series, please feel free to improve: "io_alloc" is the generic name of the new resctrl feature that enables system software to configure the portion of cache allocated for I/O traffic. On AMD systems, "io_alloc" resctrl feature is backed by AMD's L3 Smart Data Cache Injection Allocation Enforcement (SDCIAE). Introduce the architecture-specific functions that resctrl fs should call to enable, disable, or check status of the "io_alloc" feature. Change SDCIAE state by setting (to enable) or clearing (to disable) bit 1 of MSR_IA32_L3_QOS_EXT_CFG on all logical processors within the cache domain. The SDCIAE feature details are documented in APM [1] available from [2]. [1] AMD64 Architecture Programmer's Manual Volume 2: System Programming Publication # 24593 Revision 3.41 section 19.4.7 L3 Smart Data Cache Injection Allocation Enforcement (SDCIAE) > > Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537 # [2] (please move to end of tags) > Signed-off-by: Babu Moger > Reviewed-by: Reinette Chatre > --- ... > +static void _resctrl_sdciae_enable(struct rdt_resource *r, bool enable) > +{ > + struct rdt_ctrl_domain *d; > + > + /* Walking r->ctrl_domains, ensure it can't race with cpuhp */ > + lockdep_assert_cpus_held(); > + > + /* Update L3_QOS_EXT_CFG MSR on all the CPUs in all domains */ "L3_QOS_EXT_CFG MSR" -> MSR_IA32_L3_QOS_EXT_CFG (to match touchups needed to ABMC series) > + list_for_each_entry(d, &r->ctrl_domains, hdr.list) > + on_each_cpu_mask(&d->hdr.cpu_mask, resctrl_sdciae_set_one_amd, &enable, 1); > +} > + > +int resctrl_arch_io_alloc_enable(struct rdt_resource *r, bool enable) > +{ > + struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r); > + > + if (hw_res->r_resctrl.cache.io_alloc_capable && > + hw_res->sdciae_enabled != enable) { > + _resctrl_sdciae_enable(r, enable); > + hw_res->sdciae_enabled = enable; > + } > + > + return 0; > +} > diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h > index 5e3c41b36437..70f5317f1ce4 100644 > --- a/arch/x86/kernel/cpu/resctrl/internal.h > +++ b/arch/x86/kernel/cpu/resctrl/internal.h > @@ -37,6 +37,9 @@ struct arch_mbm_state { > u64 prev_msr; > }; > > +/* Setting bit 1 in L3_QOS_EXT_CFG enables the SDCIAE feature. */ "L3_QOS_EXT_CFG" -> MSR_IA32_L3_QOS_EXT_CFG Reinette