[PATCH 0/2] x86/CPU/AMD: Add support for Extended Topology Enumeration

[PATCH 0/2] x86/CPU/AMD: Add support for Extended Topology Enumeration

[Suravee Suthikulpanit]

Linux currently provides function detect_extended_topology()
for parsing CPUID Fn0xB and derive CPU topology information.
Therefore, also call this function in AMD code path.

Thanks,
Suravee

Suravee Suthikulpanit (2):
  x86/CPU: Modify detect_extended_topology() to return result
  x86/CPU/AMD: Derive CPU topology from CPUID Fn0xB when available

 arch/x86/include/asm/processor.h |  2 +-
 arch/x86/kernel/cpu/amd.c        | 16 ++++++++++++----
 arch/x86/kernel/cpu/topology.c   |  8 ++++----
 3 files changed, 17 insertions(+), 9 deletions(-)

-- 
2.7.4

[PATCH 1/2] x86/CPU: Modify detect_extended_topology() to return result

[Suravee Suthikulpanit]

Current implementation does not communicate whether it can successfully
detect CPUID Fn0x0000000B information. Therefore, modify the function
to return success or error codes. This will be used by subsequent patches.

Reviewed-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
---
 arch/x86/include/asm/processor.h | 2 +-
 arch/x86/kernel/cpu/topology.c   | 8 ++++----
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index b0ccd48..2a5d5ed 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -193,7 +193,7 @@ extern u32 get_scattered_cpuid_leaf(unsigned int level,
 extern unsigned int init_intel_cacheinfo(struct cpuinfo_x86 *c);
 extern void init_amd_cacheinfo(struct cpuinfo_x86 *c);
 
-extern void detect_extended_topology(struct cpuinfo_x86 *c);
+extern int detect_extended_topology(struct cpuinfo_x86 *c);
 extern void detect_ht(struct cpuinfo_x86 *c);
 
 #ifdef CONFIG_X86_32
diff --git a/arch/x86/kernel/cpu/topology.c b/arch/x86/kernel/cpu/topology.c
index b099024..81c0afb 100644
--- a/arch/x86/kernel/cpu/topology.c
+++ b/arch/x86/kernel/cpu/topology.c
@@ -27,7 +27,7 @@
  * exists, use it for populating initial_apicid and cpu topology
  * detection.
  */
-void detect_extended_topology(struct cpuinfo_x86 *c)
+int detect_extended_topology(struct cpuinfo_x86 *c)
 {
 #ifdef CONFIG_SMP
 	unsigned int eax, ebx, ecx, edx, sub_index;
@@ -36,7 +36,7 @@ void detect_extended_topology(struct cpuinfo_x86 *c)
 	static bool printed;
 
 	if (c->cpuid_level < 0xb)
-		return;
+		return -1;
 
 	cpuid_count(0xb, SMT_LEVEL, &eax, &ebx, &ecx, &edx);
 
@@ -44,7 +44,7 @@ void detect_extended_topology(struct cpuinfo_x86 *c)
 	 * check if the cpuid leaf 0xb is actually implemented.
 	 */
 	if (ebx == 0 || (LEAFB_SUBTYPE(ecx) != SMT_TYPE))
-		return;
+		return -1;
 
 	set_cpu_cap(c, X86_FEATURE_XTOPOLOGY);
 
@@ -95,6 +95,6 @@ void detect_extended_topology(struct cpuinfo_x86 *c)
 			       c->cpu_core_id);
 		printed = 1;
 	}
-	return;
 #endif
+	return 0;
 }
-- 
2.7.4

[PATCH 2/2] x86/CPU/AMD: Derive CPU topology from CPUID Fn0xB

[Suravee Suthikulpanit]

Derive topology information from Extended Topology Enumeration
(CPUID Fn0x0000000B) when the information is available.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
---
 arch/x86/kernel/cpu/amd.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 2c1a9f2..2b40144 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -338,10 +338,18 @@ static void amd_get_topology(struct cpuinfo_x86 *c)
 			c->cu_id = ebx & 0xff;
 
 		if (c->x86 >= 0x17) {
-			c->cpu_core_id = ebx & 0xff;
+			int err = detect_extended_topology(c);
 
-			if (smp_num_siblings > 1)
-				c->x86_max_cores /= smp_num_siblings;
+			if (err) {
+				c->cpu_core_id = ebx & 0xff;
+
+				if (smp_num_siblings > 1)
+					c->x86_max_cores /= smp_num_siblings;
+			} else {
+				int bits = get_count_order(c->x86_max_cores);
+
+				c->x86_coreid_bits = get_count_order(bits);
+			}
 		}
 
 		cacheinfo_amd_init_llc_id(c, cpu, node_id);
@@ -378,7 +386,6 @@ static void amd_detect_cmp(struct cpuinfo_x86 *c)
 	c->phys_proc_id = c->initial_apicid >> bits;
 	/* use socket ID also for last level cache */
 	per_cpu(cpu_llc_id, cpu) = c->phys_proc_id;
-	amd_get_topology(c);
 }
 
 u16 amd_get_nb_id(int cpu)
@@ -823,6 +830,7 @@ static void init_amd(struct cpuinfo_x86 *c)
 	/* Multi core CPU? */
 	if (c->extended_cpuid_level >= 0x80000008) {
 		amd_detect_cmp(c);
+		amd_get_topology(c);
 		srat_detect_node(c);
 	}
 
-- 
2.7.4

Re: [PATCH 0/2] x86/CPU/AMD: Add support for Extended Topology Enumeration

[Ingo Molnar]

* Suravee Suthikulpanit <suravee.suthikulpanit@amd.com> wrote:

> Linux currently provides function detect_extended_topology()
> for parsing CPUID Fn0xB and derive CPU topology information.
> Therefore, also call this function in AMD code path.
> 
> Thanks,
> Suravee
> 
> Suravee Suthikulpanit (2):
>   x86/CPU: Modify detect_extended_topology() to return result
>   x86/CPU/AMD: Derive CPU topology from CPUID Fn0xB when available
> 
>  arch/x86/include/asm/processor.h |  2 +-
>  arch/x86/kernel/cpu/amd.c        | 16 ++++++++++++----
>  arch/x86/kernel/cpu/topology.c   |  8 ++++----
>  3 files changed, 17 insertions(+), 9 deletions(-)

Which tree is this again? The second patch does not apply to -linus or -tip.

Thanks,

	Ingo

Re: [PATCH 0/2] x86/CPU/AMD: Add support for Extended Topology Enumeration

[David Rientjes]

On Tue, 27 Mar 2018, Ingo Molnar wrote:

> > Linux currently provides function detect_extended_topology()
> > for parsing CPUID Fn0xB and derive CPU topology information.
> > Therefore, also call this function in AMD code path.
> > 
> > Thanks,
> > Suravee
> > 
> > Suravee Suthikulpanit (2):
> >   x86/CPU: Modify detect_extended_topology() to return result
> >   x86/CPU/AMD: Derive CPU topology from CPUID Fn0xB when available
> > 
> >  arch/x86/include/asm/processor.h |  2 +-
> >  arch/x86/kernel/cpu/amd.c        | 16 ++++++++++++----
> >  arch/x86/kernel/cpu/topology.c   |  8 ++++----
> >  3 files changed, 17 insertions(+), 9 deletions(-)
> 
> Which tree is this again? The second patch does not apply to -linus or -tip.
> 

I was wondering the exact same thing today when this came across.  I found 
it's based on Suravee's other patch series posted today entitled "x86/CPU: 
Update AMD Last-Level-Cache Information".

https://marc.info/?l=linux-kernel&m=152204614503522
1522046116-22578-1-git-send-email-suravee.suthikulpanit@amd.com

Re: [PATCH 0/2] x86/CPU/AMD: Add support for Extended Topology Enumeration

[Suravee Suthikulpanit]

Hi All,

On 3/27/18 1:52 PM, David Rientjes wrote:
> On Tue, 27 Mar 2018, Ingo Molnar wrote:
> 
>>> Linux currently provides function detect_extended_topology()
>>> for parsing CPUID Fn0xB and derive CPU topology information.
>>> Therefore, also call this function in AMD code path.
>>>
>>> Thanks,
>>> Suravee
>>>
>>> Suravee Suthikulpanit (2):
>>>    x86/CPU: Modify detect_extended_topology() to return result
>>>    x86/CPU/AMD: Derive CPU topology from CPUID Fn0xB when available
>>>
>>>   arch/x86/include/asm/processor.h |  2 +-
>>>   arch/x86/kernel/cpu/amd.c        | 16 ++++++++++++----
>>>   arch/x86/kernel/cpu/topology.c   |  8 ++++----
>>>   3 files changed, 17 insertions(+), 9 deletions(-)
>>
>> Which tree is this again? The second patch does not apply to -linus or -tip.
>>
> 
> I was wondering the exact same thing today when this came across.  I found
> it's based on Suravee's other patch series posted today entitled "x86/CPU:
> Update AMD Last-Level-Cache Information".
> 
> https://marc.info/?l=linux-kernel&m=152204614503522
> 1522046116-22578-1-git-send-email-suravee.suthikulpanit@amd.com
> 

Sorry for failing to mention the dependency on the other series here
(https://lkml.org/lkml/2018/3/26/24).

Suravee

Re: [PATCH 2/2] x86/CPU/AMD: Derive CPU topology from CPUID Fn0xB

[Suravee Suthikulpanit]

Hi All,

On 3/26/18 3:05 PM, Suravee Suthikulpanit wrote:
> Derive topology information from Extended Topology Enumeration
> (CPUID Fn0x0000000B) when the information is available.
> 
> Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
> ---
>   arch/x86/kernel/cpu/amd.c | 16 ++++++++++++----
>   1 file changed, 12 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
> index 2c1a9f2..2b40144 100644
> --- a/arch/x86/kernel/cpu/amd.c
> +++ b/arch/x86/kernel/cpu/amd.c
> @@ -338,10 +338,18 @@ static void amd_get_topology(struct cpuinfo_x86 *c)
>   			c->cu_id = ebx & 0xff;
>   
>   		if (c->x86 >= 0x17) {
> -			c->cpu_core_id = ebx & 0xff;
> +			int err = detect_extended_topology(c);
>   
> -			if (smp_num_siblings > 1)
> -				c->x86_max_cores /= smp_num_siblings;
> +			if (err) {
> +				c->cpu_core_id = ebx & 0xff;
> +
> +				if (smp_num_siblings > 1)
> +					c->x86_max_cores /= smp_num_siblings;
> +			} else {
> +				int bits = get_count_order(c->x86_max_cores);
> +
> +				c->x86_coreid_bits = get_count_order(bits);
> +			}
>   		}

I made a mistake here in the attempt to clean up the code. I'll send out V2 to fix this.

Thanks,
Suravee