[v2,2/2] x86/cpuidle: support Cannon Lake (again)

Commit Message

Jan Beulich April 2, 2020, 8:24 a.m. UTC

As per SDM rev 071 Cannon Lake has
- no CC3 residency MSR at 3FC,
- a CC1 residency MSR ar 660 (like various Atoms),
- a useless (always zero) CC3 residency MSR at 662.
Hence it needs a separate case label.

Signed-off-by: Jan Beulich <[e-mail]>
---
v2: Split. This patch is beign submitted more for completeness than with
    the expectation that it would get acked, as per the v1 feedback.
---
Using the MSR cross reference in the same SDM revision one might even
get the impression that further MSRs are unavailable, but newer CPUs
don't appear to be consistently listed there at all, so may rather be a
doc shortcoming. I've pointed this out to Intel, but I'm not expecting
swift feedback.

Patch

--- a/xen/arch/x86/acpi/cpu_idle.c
+++ b/xen/arch/x86/acpi/cpu_idle.c
@@ -69,7 +69,7 @@ 
 #define GET_PC8_RES(val)  GET_HW_RES_IN_NS(0x630, val) /* some Haswells only */
 #define GET_PC9_RES(val)  GET_HW_RES_IN_NS(0x631, val) /* some Haswells only */
 #define GET_PC10_RES(val) GET_HW_RES_IN_NS(0x632, val) /* some Haswells only */
-#define GET_CC1_RES(val)  GET_HW_RES_IN_NS(0x660, val) /* Silvermont only */
+#define GET_CC1_RES(val)  GET_HW_RES_IN_NS(0x660, val)
 #define GET_CC3_RES(val)  GET_HW_RES_IN_NS(0x3FC, val)
 #define GET_CC6_RES(val)  GET_HW_RES_IN_NS(0x3FD, val)
 #define GET_CC7_RES(val)  GET_HW_RES_IN_NS(0x3FE, val) /* SNB onwards */
@@ -201,6 +201,16 @@  static void do_get_hw_residencies(void *
         GET_CC3_RES(hw_res->cc3);
         GET_CC6_RES(hw_res->cc6);
         break;
+    /* Cannon Lake */
+    case 0x66:
+        GET_PC2_RES(hw_res->pc2);
+        GET_PC3_RES(hw_res->pc3);
+        GET_PC6_RES(hw_res->pc6);
+        GET_PC7_RES(hw_res->pc7);
+        GET_CC1_RES(hw_res->cc1);
+        GET_CC6_RES(hw_res->cc6);
+        GET_CC7_RES(hw_res->cc7);
+        break;
     /* Xeon Phi Knights Landing */
     case 0x57:
     /* Xeon Phi Knights Mill */