Re: [PATCH v9 05/13] x86/resctrl: Detect and configure Slow Memory Bandwidth Allocation

[Reinette Chatre]

Hi Babu,

On 12/1/2022 7:36 AM, Babu Moger wrote:
> The QoS slow memory configuration details are available via
> CPUID_Fn80000020_EDX_x02. Detect the available details and
> initialize the rest to defaults.
> 
> Signed-off-by: Babu Moger <babu.moger@xxxxxxx>
> ---
>  arch/x86/include/asm/msr-index.h          |    1 +
>  arch/x86/kernel/cpu/resctrl/core.c        |   36 +++++++++++++++++++++++++++--
>  arch/x86/kernel/cpu/resctrl/ctrlmondata.c |    2 +-
>  arch/x86/kernel/cpu/resctrl/rdtgroup.c    |    8 ++++--
>  4 files changed, 41 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h
> index 37ff47552bcb..e0a40027aa62 100644
> --- a/arch/x86/include/asm/msr-index.h
> +++ b/arch/x86/include/asm/msr-index.h
> @@ -1061,6 +1061,7 @@
>  
>  /* - AMD: */
>  #define MSR_IA32_MBA_BW_BASE		0xc0000200
> +#define MSR_IA32_SMBA_BW_BASE		0xc0000280
>  
>  /* MSR_IA32_VMX_MISC bits */
>  #define MSR_IA32_VMX_MISC_INTEL_PT                 (1ULL << 14)
> diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
> index 10a8c9d96f32..b4fc851f6489 100644
> --- a/arch/x86/kernel/cpu/resctrl/core.c
> +++ b/arch/x86/kernel/cpu/resctrl/core.c
> @@ -162,6 +162,13 @@ bool is_mba_sc(struct rdt_resource *r)
>  	if (!r)
>  		return rdt_resources_all[RDT_RESOURCE_MBA].r_resctrl.membw.mba_sc;
>  
> +	/*
> +	 * The software controller support is only applicable to MBA resource.
> +	 * Make sure to check for resource type.
> +	 */
> +	if (r->rid != RDT_RESOURCE_MBA)
> +		return false;
> +
>  	return r->membw.mba_sc;
>  }
>  
> @@ -225,9 +232,15 @@ static bool __rdt_get_mem_config_amd(struct rdt_resource *r)
>  	struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
>  	union cpuid_0x10_3_eax eax;
>  	union cpuid_0x10_x_edx edx;
> -	u32 ebx, ecx;
> +	u32 ebx, ecx, subleaf;
>  
> -	cpuid_count(0x80000020, 1, &eax.full, &ebx, &ecx, &edx.full);
> +	/*
> +	 * Query CPUID_Fn80000020_EDX_x01 for MBA and
> +	 * CPUID_Fn80000020_EDX_x02 for SMBA
> +	 */
> +	subleaf = (r->rid == RDT_RESOURCE_SMBA) ? 2 :  1;
> +
> +	cpuid_count(0x80000020, subleaf, &eax.full, &ebx, &ecx, &edx.full);
>  	hw_res->num_closid = edx.split.cos_max + 1;
>  	r->default_ctrl = MAX_MBA_BW_AMD;
>  
> @@ -750,6 +763,19 @@ static __init bool get_mem_config(void)
>  	return false;
>  }
>  
> +static __init bool get_slow_mem_config(void)
> +{
> +	struct rdt_hw_resource *hw_res = &rdt_resources_all[RDT_RESOURCE_SMBA];
> +
> +	if (!rdt_cpu_has(X86_FEATURE_SMBA))
> +		return false;
> +
> +	if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
> +		return __rdt_get_mem_config_amd(&hw_res->r_resctrl);
> +
> +	return false;
> +}
> +
>  static __init bool get_rdt_alloc_resources(void)
>  {
>  	struct rdt_resource *r;
> @@ -780,6 +806,9 @@ static __init bool get_rdt_alloc_resources(void)
>  	if (get_mem_config())
>  		ret = true;
>  
> +	if (get_slow_mem_config())
> +		ret = true;
> +
>  	return ret;
>  }
>  
> @@ -869,6 +898,9 @@ static __init void rdt_init_res_defs_amd(void)
>  		} else if (r->rid == RDT_RESOURCE_MBA) {
>  			hw_res->msr_base = MSR_IA32_MBA_BW_BASE;
>  			hw_res->msr_update = mba_wrmsr_amd;
> +		} else if (r->rid == RDT_RESOURCE_SMBA) {
> +			hw_res->msr_base = MSR_IA32_SMBA_BW_BASE;
> +			hw_res->msr_update = mba_wrmsr_amd;
>  		}
>  	}
>  }
> diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
> index 1df0e3262bca..2dd4b8c47f23 100644
> --- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
> +++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
> @@ -209,7 +209,7 @@ static int parse_line(char *line, struct resctrl_schema *s,
>  	unsigned long dom_id;
>  
>  	if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP &&
> -	    r->rid == RDT_RESOURCE_MBA) {
> +	    (r->rid == RDT_RESOURCE_MBA || r->rid == RDT_RESOURCE_SMBA)) {
>  		rdt_last_cmd_puts("Cannot pseudo-lock MBA resource\n");
>  		return -EINVAL;
>  	}
> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> index e5a48f05e787..8a3dafc0dbf7 100644
> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
> @@ -1213,7 +1213,7 @@ static bool rdtgroup_mode_test_exclusive(struct rdtgroup *rdtgrp)
>  
>  	list_for_each_entry(s, &resctrl_schema_all, list) {
>  		r = s->res;
> -		if (r->rid == RDT_RESOURCE_MBA)
> +		if (r->rid == RDT_RESOURCE_MBA || r->rid == RDT_RESOURCE_SMBA)
>  			continue;
>  		has_cache = true;
>  		list_for_each_entry(d, &r->domains, list) {
> @@ -1402,7 +1402,8 @@ static int rdtgroup_size_show(struct kernfs_open_file *of,
>  					ctrl = resctrl_arch_get_config(r, d,
>  								       closid,
>  								       type);
> -				if (r->rid == RDT_RESOURCE_MBA)
> +				if (r->rid == RDT_RESOURCE_MBA ||
> +				    r->rid == RDT_RESOURCE_SMBA)
>  					size = ctrl;
>  				else
>  					size = rdtgroup_cbm_to_size(r, d, ctrl);
> @@ -2845,7 +2846,8 @@ static int rdtgroup_init_alloc(struct rdtgroup *rdtgrp)
>  
>  	list_for_each_entry(s, &resctrl_schema_all, list) {
>  		r = s->res;
> -		if (r->rid == RDT_RESOURCE_MBA) {
> +		if (r->rid == RDT_RESOURCE_MBA ||
> +		    r->rid == RDT_RESOURCE_SMBA) {
>  			rdtgroup_init_mba(r, rdtgrp->closid);
>  			if (is_mba_sc(r))
>  				continue;
> 
> 

Reviewed-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>

Reinette