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[Xen-devel] [PATCH] ACPI: add _PDC input override mechanism



In order to have Dom0 call _PDC with input fully representing Xen's
capabilities, and in order to avoid building knowledge of Xen
implementation details into Dom0, this provides a mechanism by which
the Dom0 kernel can, once it filled the _PDC input buffer according to
its own knowledge, present the buffer to Xen to apply overrides for
the parts of the C-, P-, and T-state management that it controls. This
is particularly to address the dependency of Xen using MWAIT to enter
certain C-states on the availability of the break-on-interrupt
extension (which the Dom0 kernel should have no need to know about).

The patch, in order to apply correctly, depends on the one titled "pm:
don't truncate processors' ACPI IDs to 8 bits" sent at the end of last
week.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>

--- a/xen/arch/ia64/linux-xen/acpi.c
+++ b/xen/arch/ia64/linux-xen/acpi.c
@@ -241,6 +241,13 @@ int get_cpu_id(u32 acpi_id)
 
        return -1;
 }
+
+int arch_acpi_set_pdc_bits(u32 acpi_id, u32 *pdc, u32 mask)
+{
+       pdc[2] |= ACPI_PDC_EST_CAPABILITY_SMP & mask;
+       return 0;
+}
+
 #endif
 
 static int __init
--- a/xen/arch/x86/acpi/cpu_idle.c
+++ b/xen/arch/x86/acpi/cpu_idle.c
@@ -643,12 +643,6 @@ static int cpuidle_init_cpu(int cpu)
     return 0;
 }
 
-#define CPUID_MWAIT_LEAF (5)
-#define CPUID5_ECX_EXTENSIONS_SUPPORTED (0x1)
-#define CPUID5_ECX_INTERRUPT_BREAK      (0x2)
-
-#define MWAIT_ECX_INTERRUPT_BREAK       (0x1)
-
 #define MWAIT_SUBSTATE_MASK (0xf)
 #define MWAIT_SUBSTATE_SIZE (4)
 
--- a/xen/arch/x86/acpi/lib.c
+++ b/xen/arch/x86/acpi/lib.c
@@ -81,3 +81,47 @@ unsigned int acpi_get_processor_id(unsig
 
        return INVALID_ACPIID;
 }
+
+static void get_mwait_ecx(void *info)
+{
+       *(u32 *)info = cpuid_ecx(CPUID_MWAIT_LEAF);
+}
+
+int arch_acpi_set_pdc_bits(u32 acpi_id, u32 *pdc, u32 mask)
+{
+       unsigned int cpu = get_cpu_id(acpi_id);
+       struct cpuinfo_x86 *c;
+       u32 ecx;
+
+       if (!(acpi_id + 1))
+               c = &boot_cpu_data;
+       else if (cpu >= NR_CPUS || !cpu_online(cpu))
+               return -EINVAL;
+       else
+               c = cpu_data + cpu;
+
+       pdc[2] |= ACPI_PDC_C_CAPABILITY_SMP & mask;
+
+       if (cpu_has(c, X86_FEATURE_EST))
+               pdc[2] |= ACPI_PDC_EST_CAPABILITY_SWSMP & mask;
+
+       if (cpu_has(c, X86_FEATURE_ACPI))
+               pdc[2] |= ACPI_PDC_T_FFH & mask;
+
+       /*
+        * If mwait/monitor or its break-on-interrupt extension are
+        * unsupported, Cx_FFH will be disabled.
+        */
+       if (!cpu_has(c, X86_FEATURE_MWAIT) ||
+           c->cpuid_level < CPUID_MWAIT_LEAF)
+               ecx = 0;
+       else if (c == &boot_cpu_data || cpu == smp_processor_id())
+               ecx = cpuid_ecx(CPUID_MWAIT_LEAF);
+       else
+               on_selected_cpus(cpumask_of(cpu), get_mwait_ecx, &ecx, 1);
+       if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
+           !(ecx & CPUID5_ECX_INTERRUPT_BREAK))
+               pdc[2] &= ~(ACPI_PDC_C_C1_FFH | ACPI_PDC_C_C2C3_FFH);
+
+       return 0;
+}
--- a/xen/arch/x86/platform_hypercall.c
+++ b/xen/arch/x86/platform_hypercall.c
@@ -416,6 +416,15 @@ ret_t do_platform_op(XEN_GUEST_HANDLE(xe
             ret = -EINVAL;
             break;
 
+        case XEN_PM_PDC:
+        {
+            XEN_GUEST_HANDLE(uint32) pdc;
+
+            guest_from_compat_handle(pdc, op->u.set_pminfo.u.pdc);
+            ret = acpi_set_pdc_bits(op->u.set_pminfo.id, pdc);
+        }
+        break;
+
         default:
             ret = -EINVAL;
             break;
--- a/xen/drivers/acpi/pmstat.c
+++ b/xen/drivers/acpi/pmstat.c
@@ -517,3 +517,34 @@ int do_pm_op(struct xen_sysctl_pm_op *op
 
     return ret;
 }
+
+int acpi_set_pdc_bits(u32 acpi_id, XEN_GUEST_HANDLE(uint32) pdc)
+{
+    u32 bits[3];
+    int ret;
+
+    if ( copy_from_guest(bits, pdc, 2) )
+        ret = -EFAULT;
+    else if ( bits[0] != ACPI_PDC_REVISION_ID || !bits[1] )
+        ret = -EINVAL;
+    else if ( copy_from_guest_offset(bits + 2, pdc, 2, 1) )
+        ret = -EFAULT;
+    else
+    {
+        u32 mask = 0;
+
+        if ( xen_processor_pmbits & XEN_PROCESSOR_PM_CX )
+            mask |= ACPI_PDC_C_MASK | ACPI_PDC_SMP_C1PT;
+        if ( xen_processor_pmbits & XEN_PROCESSOR_PM_PX )
+            mask |= ACPI_PDC_P_MASK | ACPI_PDC_SMP_C1PT;
+        if ( xen_processor_pmbits & XEN_PROCESSOR_PM_TX )
+            mask |= ACPI_PDC_T_MASK | ACPI_PDC_SMP_C1PT;
+        bits[2] &= (ACPI_PDC_C_MASK | ACPI_PDC_P_MASK | ACPI_PDC_T_MASK |
+                    ACPI_PDC_SMP_C1PT) & ~mask;
+        ret = arch_acpi_set_pdc_bits(acpi_id, bits, mask);
+    }
+    if ( !ret )
+        ret = copy_to_guest_offset(pdc, 2, bits + 2, 1);
+
+    return ret;
+}
--- a/xen/include/acpi/cpufreq/processor_perf.h
+++ b/xen/include/acpi/cpufreq/processor_perf.h
@@ -3,10 +3,10 @@
 
 #include <public/platform.h>
 #include <public/sysctl.h>
+#include <xen/acpi.h>
 
 #define XEN_PX_INIT 0x80000000
 
-int get_cpu_id(u32);
 int powernow_cpufreq_init(void);
 unsigned int powernow_register_driver(void);
 unsigned int get_measured_perf(unsigned int cpu, unsigned int flag);
--- a/xen/include/acpi/pdc_intel.h
+++ b/xen/include/acpi/pdc_intel.h
@@ -4,6 +4,8 @@
 #ifndef __PDC_INTEL_H__
 #define __PDC_INTEL_H__
 
+#define ACPI_PDC_REVISION_ID           1
+
 #define ACPI_PDC_P_FFH                 (0x0001)
 #define ACPI_PDC_C_C1_HALT             (0x0002)
 #define ACPI_PDC_T_FFH                 (0x0004)
@@ -14,6 +16,7 @@
 #define ACPI_PDC_SMP_T_SWCOORD         (0x0080)
 #define ACPI_PDC_C_C1_FFH              (0x0100)
 #define ACPI_PDC_C_C2C3_FFH            (0x0200)
+#define ACPI_PDC_SMP_P_HWCOORD         (0x0800)
 
 #define ACPI_PDC_EST_CAPABILITY_SMP    (ACPI_PDC_SMP_C1PT | \
                                         ACPI_PDC_C_C1_HALT | \
@@ -22,6 +25,7 @@
 #define ACPI_PDC_EST_CAPABILITY_SWSMP  (ACPI_PDC_SMP_C1PT | \
                                         ACPI_PDC_C_C1_HALT | \
                                         ACPI_PDC_SMP_P_SWCOORD | \
+                                        ACPI_PDC_SMP_P_HWCOORD | \
                                         ACPI_PDC_P_FFH)
 
 #define ACPI_PDC_C_CAPABILITY_SMP      (ACPI_PDC_SMP_C2C3  | \
@@ -30,4 +34,17 @@
                                         ACPI_PDC_C_C1_FFH  | \
                                         ACPI_PDC_C_C2C3_FFH)
 
+#define ACPI_PDC_C_MASK                        (ACPI_PDC_C_C1_HALT | \
+                                        ACPI_PDC_C_C1_FFH | \
+                                        ACPI_PDC_SMP_C2C3 | \
+                                        ACPI_PDC_SMP_C_SWCOORD | \
+                                        ACPI_PDC_C_C2C3_FFH)
+
+#define ACPI_PDC_P_MASK                        (ACPI_PDC_P_FFH | \
+                                        ACPI_PDC_SMP_P_SWCOORD | \
+                                        ACPI_PDC_SMP_P_HWCOORD)
+
+#define ACPI_PDC_T_MASK                        (ACPI_PDC_T_FFH | \
+                                        ACPI_PDC_SMP_T_SWCOORD)
+
 #endif                         /* __PDC_INTEL_H__ */
--- a/xen/include/asm-x86/cpufeature.h
+++ b/xen/include/asm-x86/cpufeature.h
@@ -152,6 +152,10 @@
 #define boot_cpu_has(bit)      test_bit(bit, boot_cpu_data.x86_capability)
 #define cpufeat_mask(idx)       (1u << ((idx) & 31))
 
+#define CPUID_MWAIT_LEAF                5
+#define CPUID5_ECX_EXTENSIONS_SUPPORTED 0x1
+#define CPUID5_ECX_INTERRUPT_BREAK      0x2
+
 #ifdef __i386__
 #define cpu_has_vme            boot_cpu_has(X86_FEATURE_VME)
 #define cpu_has_de             boot_cpu_has(X86_FEATURE_DE)
--- a/xen/include/public/platform.h
+++ b/xen/include/public/platform.h
@@ -304,6 +304,7 @@ DEFINE_XEN_GUEST_HANDLE(xenpf_getidletim
 #define XEN_PM_CX   0
 #define XEN_PM_PX   1
 #define XEN_PM_TX   2
+#define XEN_PM_PDC  3
 
 /* Px sub info type */
 #define XEN_PX_PCT   1
@@ -401,6 +402,7 @@ struct xenpf_set_processor_pminfo {
     union {
         struct xen_processor_power          power;/* Cx: _CST/_CSD */
         struct xen_processor_performance    perf; /* Px: _PPC/_PCT/_PSS/_PSD */
+        XEN_GUEST_HANDLE(uint32)            pdc;  /* _PDC */
     } u;
 };
 typedef struct xenpf_set_processor_pminfo xenpf_set_processor_pminfo_t;
--- a/xen/include/xen/acpi.h
+++ b/xen/include/xen/acpi.h
@@ -322,6 +322,8 @@ static inline int acpi_boot_table_init(v
 
 #endif         /*!CONFIG_ACPI_BOOT*/
 
+int get_cpu_id(u32 acpi_id);
+
 unsigned int acpi_register_gsi (u32 gsi, int edge_level, int active_high_low);
 int acpi_gsi_to_irq (u32 gsi, unsigned int *irq);
 
@@ -358,6 +360,9 @@ static inline unsigned int acpi_get_csta
 static inline void acpi_set_cstate_limit(unsigned int new_limit) { return; }
 #endif
 
+int acpi_set_pdc_bits(u32 acpi_id, XEN_GUEST_HANDLE(uint32));
+int arch_acpi_set_pdc_bits(u32 acpi_id, u32 *, u32 mask);
+
 #ifdef CONFIG_ACPI_NUMA
 int acpi_get_pxm(acpi_handle handle);
 #else


Attachment: acpi-set-pdc-bits.patch
Description: Text document

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