diff mbox series

[v3,1/2] x86/resctrl: Remove hard-coded memory bandwidth limit

Message ID 20240104212130.209490-1-babu.moger@amd.com
State New
Headers
Series [v3,1/2] x86/resctrl: Remove hard-coded memory bandwidth limit |

Commit Message

Moger, Babu Jan. 4, 2024, 9:21 p.m. UTC 
  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 the hard-coded value and detect using CPUID
command. Also update the register variables eax and edx to match the
AMD CPUID definition.

The CPUID details are documentation in the PPR listed below [1].
[1] Processor Programming Reference (PPR) Vol 1.1 for AMD Family 19h Model
11h B1 - 55901 Rev 0.25.

Fixes: 4d05bf71f157 ("x86/resctrl: Introduce AMD QOS feature")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537
Signed-off-by: Babu Moger <babu.moger@amd.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
---
v3: No change. Just updated with Reviewed-by

v2: Earlier Sent as a part of ABMC feature.
    https://lore.kernel.org/lkml/20231201005720.235639-1-babu.moger@amd.com/
    Sending it separate now. Addressed comments from Reinette about registers
    being used from Intel definition. Also updated commit message.
---
 arch/x86/kernel/cpu/resctrl/core.c     | 10 ++++------
 arch/x86/kernel/cpu/resctrl/internal.h |  1 -
 2 files changed, 4 insertions(+), 7 deletions(-)

Comments

Reinette Chatre Jan. 5, 2024, 9:14 p.m. UTC | #1 
Hi Babu,

On 1/4/2024 1:21 PM, Babu Moger wrote:
> 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 the hard-coded value and detect using CPUID
> command. Also update the register variables eax and edx to match the
> AMD CPUID definition.
> 
> The CPUID details are documentation in the PPR listed below [1].

"are documentation" -> "are documented"?

> [1] Processor Programming Reference (PPR) Vol 1.1 for AMD Family 19h Model
> 11h B1 - 55901 Rev 0.25.
> 
> Fixes: 4d05bf71f157 ("x86/resctrl: Introduce AMD QOS feature")
> Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537
> Signed-off-by: Babu Moger <babu.moger@amd.com>
> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>

Looking at "Ordering of commit tags" in Documentation/process/maintainer-tip.rst
I believe "Link:" should be the last entry.

Reinette
Moger, Babu Jan. 5, 2024, 11:51 p.m. UTC | #2 
Hi Reinette,

On 1/5/2024 3:14 PM, Reinette Chatre wrote:
> Hi Babu,
>
> On 1/4/2024 1:21 PM, Babu Moger wrote:
>> 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 the hard-coded value and detect using CPUID
>> command. Also update the register variables eax and edx to match the
>> AMD CPUID definition.
>>
>> The CPUID details are documentation in the PPR listed below [1].
> "are documentation" -> "are documented"?
Sure.
>
>> [1] Processor Programming Reference (PPR) Vol 1.1 for AMD Family 19h Model
>> 11h B1 - 55901 Rev 0.25.
>>
>> Fixes: 4d05bf71f157 ("x86/resctrl: Introduce AMD QOS feature")
>> Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537
>> Signed-off-by: Babu Moger <babu.moger@amd.com>
>> Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
> Looking at "Ordering of commit tags" in Documentation/process/maintainer-tip.rst
> I believe "Link:" should be the last entry.

Sure.

thanks

Babu
diff mbox series

Patch

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 19e0681f0435..d04371e851b4 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -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;
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index a4f1aa15f0a2..d2979748fae4 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -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)