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x86/resctrl: Remove hard-coded memory bandwidth limit

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The QOS Memory Bandwidth Enforcement Limit is reported by
CPUID_Fn80000020_EAX_x01 and CPUID_Fn80000020_EAX_x02:

  Bits	 Description
  31:0	 BW_LEN: Size of the QOS Memory Bandwidth Enforcement Limit.

Newer processors can support higher bandwidth limit than the current
hard-coded value. Remove latter and detect using CPUID instead. Also,
update the register variables eax and edx to match the AMD CPUID
definition.

The CPUID details are documented in the Processor Programming Reference
(PPR) Vol 1.1 for AMD Family 19h Model 11h B1 - 55901 Rev 0.25 in the
Link tag below.

Fixes: 4d05bf71f157 ("x86/resctrl: Introduce AMD QOS feature")
Signed-off-by: Babu Moger <babu.moger@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537
Link: https://lore.kernel.org/r/c26a8ca79d399ed076cf8bf2e9fbc58048808289.1705359148.git.babu.moger@amd.com
This commit is contained in:
Babu Moger 2024-01-15 16:52:27 -06:00 committed by Borislav Petkov (AMD)
parent 1b908debf5
commit 0976783bb1
2 changed files with 4 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
arch/x86/kernel/cpu/resctrl/core.c
View File

@ -231,9 +231,7 @@ static bool __get_mem_config_intel(struct rdt_resource *r)
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, subleaf;
u32 eax, ebx, ecx, edx, subleaf;
/*
* Query CPUID_Fn80000020_EDX_x01 for MBA and
@ -241,9 +239,9 @@ static bool __rdt_get_mem_config_amd(struct rdt_resource *r)
*/
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;
cpuid_count(0x80000020, subleaf, &eax, &ebx, &ecx, &edx);
hw_res->num_closid = edx + 1;
r->default_ctrl = 1 << eax;
/* AMD does not use delay */
r->membw.delay_linear = false;

1
arch/x86/kernel/cpu/resctrl/internal.h
View File

@ -18,7 +18,6 @@
#define MBM_OVERFLOW_INTERVAL 1000
#define MAX_MBA_BW 100u
#define MBA_IS_LINEAR 0x4
#define MAX_MBA_BW_AMD 0x800
#define MBM_CNTR_WIDTH_OFFSET_AMD 20
#define RMID_VAL_ERROR BIT_ULL(63)