Hi Babu,
On 19/01/2024 18:22, Babu Moger wrote:
> ABMC feature details are reported via CPUID Fn8000_0020_EBX_x5.
> Bits Description
> 15:0 MAX_ABMC Maximum Supported Assignable Bandwidth
> Monitoring Counter ID + 1
>
> Detect the feature details and update
> /sys/fs/resctrl/info/L3_MON/mon_features.
>
> If the system supports Assignable Bandwidth Monitoring Counters (ABMC),
> the output will have additional text.
> $ cat /sys/fs/resctrl/info/L3_MON/mon_features
> mbm_assign_capable
>
> The feature details are documented in APM listed below [1].
> [1] AMD64 Architecture Programmer's Manual Volume 2: System Programming
> Publication # 24593 Revision 3.41 section 19.3.3.3 Assignable Bandwidth
> Monitoring (ABMC).
> diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
> index 4efe2d6a9eb7..f40ee271a5c7 100644
> --- a/arch/x86/kernel/cpu/resctrl/core.c
> +++ b/arch/x86/kernel/cpu/resctrl/core.c
> @@ -303,6 +303,17 @@ static void rdt_get_cdp_l2_config(void)
> rdt_get_cdp_config(RDT_RESOURCE_L2);
> }
>
> +static void rdt_get_abmc_cfg(struct rdt_resource *r)
> +{
> + struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
> + u32 eax, ebx, ecx, edx;
> +
> + r->mbm_assign_capable = true;
> + /* Query CPUID_Fn80000020_EBX_x05 for number of ABMC counters */
> + cpuid_count(0x80000020, 5, &eax, &ebx, &ecx, &edx);
> + hw_res->mbm_assignable_counters = (ebx & 0xFFFF) + 1;
Please put the mbm_assignable_counters field in struct rdt_resource. The filesystem code
needs to access this to allocate/free counters and report how many are available.
After all this gets split and the filesystem code moves to /fs/, the rdt_hw_resrouce
structure is inaccessible to the filesystem code.
> +}
> +
> static void
> mba_wrmsr_amd(struct rdt_domain *d, struct msr_param *m, struct rdt_resource *r)
> {
> @@ -815,6 +826,12 @@ static __init bool get_rdt_alloc_resources(void)
> if (get_slow_mem_config())
> ret = true;
>
> + if (rdt_cpu_has(X86_FEATURE_ABMC)) {
> + r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;
> + rdt_get_abmc_cfg(r);
> + ret = true;
Does it make sense to report rdt_alloc_capable if the SoC has ABMC, but nothing that can
be configured?
This code would probably make more sense in the get_rdt_mon_resources().
> + }
> +
> return ret;
> }
>
> diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
> index a4f1aa15f0a2..01eb0522b42b 100644
> --- a/arch/x86/kernel/cpu/resctrl/internal.h
> +++ b/arch/x86/kernel/cpu/resctrl/internal.h
> @@ -391,6 +391,8 @@ struct rdt_parse_data {
> * resctrl_arch_get_num_closid() to avoid confusion
> * with struct resctrl_schema's property of the same name,
> * which has been corrected for features like CDP.
> + * @mbm_assignable_counters:
> + * Maximum number of assignable ABMC counters
As above, please move this to struct rdt_resource. The 'hw' version becomes private to the
arch code after the move to /fs//
> * @msr_base: Base MSR address for CBMs
> * @msr_update: Function pointer to update QOS MSRs
> * @mon_scale: cqm counter * mon_scale = occupancy in bytes
Thanks,
James
