[RFC PATCH for-4.22 v2 1/3] x86/cpu-policy: Infrastructure for CPUID leaf 0x6

Teddy Astie posted 3 patches 3 months, 1 week ago
There is a newer version of this series
[RFC PATCH for-4.22 v2 1/3] x86/cpu-policy: Infrastructure for CPUID leaf 0x6
Posted by Teddy Astie 3 months, 1 week ago
From: Jan Beulich <jbeulich@suse.com>

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Teddy Astie <teddy.astie@vates.tech>
---
v2: introduced

 xen/include/xen/lib/x86/cpu-policy.h | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/xen/include/xen/lib/x86/cpu-policy.h b/xen/include/xen/lib/x86/cpu-policy.h
index f94f23e159..c721c986cc 100644
--- a/xen/include/xen/lib/x86/cpu-policy.h
+++ b/xen/include/xen/lib/x86/cpu-policy.h
@@ -121,7 +121,32 @@ struct cpu_policy
             uint64_t :64, :64; /* Leaf 0x3 - PSN. */
             uint64_t :64, :64; /* Leaf 0x4 - Structured Cache. */
             uint64_t :64, :64; /* Leaf 0x5 - MONITOR. */
-            uint64_t :64, :64; /* Leaf 0x6 - Therm/Perf. */
+
+            /* Leaf 0x6 - Therm/Perf. */
+            struct {
+                uint32_t /* a */
+                    dts:1,
+                    turbo:1,
+                    arat:1,
+                    :4,
+                    hwp:1,
+                    hwp_notification:1,
+                    hwp_activity_window:1,
+                    hwp_epp:1,
+                    hwp_plr:1,
+                    :1,
+                    hdc:1,
+                    :2,
+                    hwp_peci:1,
+                    :2,
+                    hw_feedback:1,
+                    :12;
+                uint32_t /* b */:32;
+                uint32_t /* c */ aperfmperf:1, 
+                    :31;
+                uint32_t /* d */:32;
+            } pm;
+
             uint64_t :64, :64; /* Leaf 0x7 - Structured Features. */
             uint64_t :64, :64; /* Leaf 0x8 - rsvd */
             uint64_t :64, :64; /* Leaf 0x9 - DCA */
-- 
2.51.2



--
Teddy Astie | Vates XCP-ng Developer

XCP-ng & Xen Orchestra - Vates solutions

web: https://vates.tech
Re: [RFC PATCH for-4.22 v2 1/3] x86/cpu-policy: Infrastructure for CPUID leaf 0x6
Posted by Jan Beulich 3 months, 1 week ago
On 29.10.2025 16:59, Teddy Astie wrote:
> From: Jan Beulich <jbeulich@suse.com>
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
> Signed-off-by: Teddy Astie <teddy.astie@vates.tech>
> ---
> v2: introduced

This being a change of mine, I'm not happy for the title to have changed, and
for the (little bit of) description to have been dropped.

> --- a/xen/include/xen/lib/x86/cpu-policy.h
> +++ b/xen/include/xen/lib/x86/cpu-policy.h
> @@ -121,7 +121,32 @@ struct cpu_policy
>              uint64_t :64, :64; /* Leaf 0x3 - PSN. */
>              uint64_t :64, :64; /* Leaf 0x4 - Structured Cache. */
>              uint64_t :64, :64; /* Leaf 0x5 - MONITOR. */
> -            uint64_t :64, :64; /* Leaf 0x6 - Therm/Perf. */
> +
> +            /* Leaf 0x6 - Therm/Perf. */
> +            struct {
> +                uint32_t /* a */
> +                    dts:1,
> +                    turbo:1,
> +                    arat:1,
> +                    :4,
> +                    hwp:1,
> +                    hwp_notification:1,
> +                    hwp_activity_window:1,
> +                    hwp_epp:1,
> +                    hwp_plr:1,
> +                    :1,
> +                    hdc:1,
> +                    :2,
> +                    hwp_peci:1,
> +                    :2,
> +                    hw_feedback:1,
> +                    :12;
> +                uint32_t /* b */:32;
> +                uint32_t /* c */ aperfmperf:1, 
> +                    :31;
> +                uint32_t /* d */:32;
> +            } pm;
> +
>              uint64_t :64, :64; /* Leaf 0x7 - Structured Features. */
>              uint64_t :64, :64; /* Leaf 0x8 - rsvd */
>              uint64_t :64, :64; /* Leaf 0x9 - DCA */

As I had said, this (really: the use of these bits in the host policy) actually
requires an adjustment to cpu-policy.c as well, which I'm carrying as a separate,
prereq change (re-produced below). May I suggest that your work go on top of mine
(which I'll post once we have branched 4.21 off)?

Jan

x86/cpu-policy: move invocation of recalculate_misc()

The function is about guest exposure of features / leaves. There's no need
for it to be applied on the host policy. In fact doing so gets in the way
of using the host policy in certain places.

Signed-off-by: Jan Beulich <jbeulich@suse.com>

--- a/xen/arch/x86/cpu-policy.c
+++ b/xen/arch/x86/cpu-policy.c
@@ -424,7 +424,6 @@ void __init calculate_host_policy(void)
     x86_cpu_featureset_to_policy(boot_cpu_data.x86_capability, p);
     recalculate_xstate(p);
     recalculate_tile(p);
-    recalculate_misc(p);
 
     /* When vPMU is disabled, drop it from the host policy. */
     if ( vpmu_mode == XENPMU_MODE_OFF )
@@ -705,6 +704,7 @@ static void __init calculate_pv_max_poli
     unsigned int i;
 
     *p = host_cpu_policy;
+    recalculate_misc(p);
 
     guest_common_max_leaves(p);
 
@@ -809,6 +809,7 @@ static void __init calculate_hvm_max_pol
     const uint32_t *mask;
 
     *p = host_cpu_policy;
+    recalculate_misc(p);
 
     guest_common_max_leaves(p);
Re: [RFC PATCH for-4.22 v2 1/3] x86/cpu-policy: Infrastructure for CPUID leaf 0x6
Posted by Teddy Astie 3 months, 1 week ago
Le 30/10/2025 à 08:14, Jan Beulich a écrit :
> On 29.10.2025 16:59, Teddy Astie wrote:
>> From: Jan Beulich <jbeulich@suse.com>
>>
>> Signed-off-by: Jan Beulich <jbeulich@suse.com>
>> Signed-off-by: Teddy Astie <teddy.astie@vates.tech>
>> ---
>> v2: introduced
> 
> This being a change of mine, I'm not happy for the title to have changed, and
> for the (little bit of) description to have been dropped.
> 
>> --- a/xen/include/xen/lib/x86/cpu-policy.h
>> +++ b/xen/include/xen/lib/x86/cpu-policy.h
>> @@ -121,7 +121,32 @@ struct cpu_policy
>>               uint64_t :64, :64; /* Leaf 0x3 - PSN. */
>>               uint64_t :64, :64; /* Leaf 0x4 - Structured Cache. */
>>               uint64_t :64, :64; /* Leaf 0x5 - MONITOR. */
>> -            uint64_t :64, :64; /* Leaf 0x6 - Therm/Perf. */
>> +
>> +            /* Leaf 0x6 - Therm/Perf. */
>> +            struct {
>> +                uint32_t /* a */
>> +                    dts:1,
>> +                    turbo:1,
>> +                    arat:1,
>> +                    :4,
>> +                    hwp:1,
>> +                    hwp_notification:1,
>> +                    hwp_activity_window:1,
>> +                    hwp_epp:1,
>> +                    hwp_plr:1,
>> +                    :1,
>> +                    hdc:1,
>> +                    :2,
>> +                    hwp_peci:1,
>> +                    :2,
>> +                    hw_feedback:1,
>> +                    :12;
>> +                uint32_t /* b */:32;
>> +                uint32_t /* c */ aperfmperf:1,
>> +                    :31;
>> +                uint32_t /* d */:32;
>> +            } pm;
>> +
>>               uint64_t :64, :64; /* Leaf 0x7 - Structured Features. */
>>               uint64_t :64, :64; /* Leaf 0x8 - rsvd */
>>               uint64_t :64, :64; /* Leaf 0x9 - DCA */
> 
> As I had said, this (really: the use of these bits in the host policy) actually
> requires an adjustment to cpu-policy.c as well, which I'm carrying as a separate,
> prereq change (re-produced below). May I suggest that your work go on top of mine
> (which I'll post once we have branched 4.21 off)?
> 

I'm ok with it.

> Jan
> 
> x86/cpu-policy: move invocation of recalculate_misc()
> 
> The function is about guest exposure of features / leaves. There's no need
> for it to be applied on the host policy. In fact doing so gets in the way
> of using the host policy in certain places.
> 
> Signed-off-by: Jan Beulich <jbeulich@suse.com>
> 
> --- a/xen/arch/x86/cpu-policy.c
> +++ b/xen/arch/x86/cpu-policy.c
> @@ -424,7 +424,6 @@ void __init calculate_host_policy(void)
>       x86_cpu_featureset_to_policy(boot_cpu_data.x86_capability, p);
>       recalculate_xstate(p);
>       recalculate_tile(p);
> -    recalculate_misc(p);
>   
>       /* When vPMU is disabled, drop it from the host policy. */
>       if ( vpmu_mode == XENPMU_MODE_OFF )
> @@ -705,6 +704,7 @@ static void __init calculate_pv_max_poli
>       unsigned int i;
>   
>       *p = host_cpu_policy;
> +    recalculate_misc(p);
>   
>       guest_common_max_leaves(p);
>   
> @@ -809,6 +809,7 @@ static void __init calculate_hvm_max_pol
>       const uint32_t *mask;
>   
>       *p = host_cpu_policy;
> +    recalculate_misc(p);
>   
>       guest_common_max_leaves(p);
>   
> 
> 

Teddy


--
Teddy Astie | Vates XCP-ng Developer

XCP-ng & Xen Orchestra - Vates solutions

web: https://vates.tech