qemu-devel
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[Qemu-devel] [PATCH v2] i386: Introduce ARAT CPU feature


From: Jan Kiszka
Subject: [Qemu-devel] [PATCH v2] i386: Introduce ARAT CPU feature
Date: Mon, 25 May 2015 16:06:50 +0200
User-agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666

From: Jan Kiszka <address@hidden>

ARAT signals that the APIC timer does not stop in power saving states.
As our APICs are emulated, it's fine to expose this feature to guests,
at least when asking for KVM host features or with CPU types that
include the flag. The exact model number that introduced the feature is
not known, but reports can be found that it's at least available since
Sandy Bridge.

Signed-off-by: Jan Kiszka <address@hidden>
---

Changes in v2:
 - remove feature from Intel CPU types in compat machines

 hw/i386/pc_piix.c | 10 ++++++++++
 target-i386/cpu.c | 33 ++++++++++++++++++++++++++++++++-
 target-i386/cpu.h |  3 +++
 target-i386/kvm.c |  2 ++
 4 files changed, 47 insertions(+), 1 deletion(-)

diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index 212e263..83133fa 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -312,6 +312,16 @@ static void pc_init_pci(MachineState *machine)
 
 static void pc_compat_2_3(MachineState *machine)
 {
+    x86_cpu_compat_set_features("Westmere", FEAT_6_EAX, 0, CPUID_6_EAX_ARAT);
+    x86_cpu_compat_set_features("SandyBridge", FEAT_6_EAX, 0,
+                                CPUID_6_EAX_ARAT);
+    x86_cpu_compat_set_features("IvyBridge", FEAT_6_EAX, 0, CPUID_6_EAX_ARAT);
+    x86_cpu_compat_set_features("Haswell-noTSX", FEAT_6_EAX, 0,
+                                CPUID_6_EAX_ARAT);
+    x86_cpu_compat_set_features("Haswell", FEAT_6_EAX, 0, CPUID_6_EAX_ARAT);
+    x86_cpu_compat_set_features("Broadwell-noTSC", FEAT_6_EAX, 0,
+                                CPUID_6_EAX_ARAT);
+    x86_cpu_compat_set_features("Broadwell", FEAT_6_EAX, 0, CPUID_6_EAX_ARAT);
 }
 
 static void pc_compat_2_2(MachineState *machine)
diff --git a/target-i386/cpu.c b/target-i386/cpu.c
index 3305e09..e435a08 100644
--- a/target-i386/cpu.c
+++ b/target-i386/cpu.c
@@ -284,6 +284,17 @@ static const char *cpuid_xsave_feature_name[] = {
     NULL, NULL, NULL, NULL,
 };
 
+static const char *cpuid_6_feature_name[] = {
+    NULL, NULL, "arat", NULL,
+    NULL, NULL, NULL, NULL,
+    NULL, NULL, NULL, NULL,
+    NULL, NULL, NULL, NULL,
+    NULL, NULL, NULL, NULL,
+    NULL, NULL, NULL, NULL,
+    NULL, NULL, NULL, NULL,
+    NULL, NULL, NULL, NULL,
+};
+
 #define I486_FEATURES (CPUID_FP87 | CPUID_VME | CPUID_PSE)
 #define PENTIUM_FEATURES (I486_FEATURES | CPUID_DE | CPUID_TSC | \
           CPUID_MSR | CPUID_MCE | CPUID_CX8 | CPUID_MMX | CPUID_APIC)
@@ -339,6 +350,7 @@ static const char *cpuid_xsave_feature_name[] = {
           CPUID_7_0_EBX_ERMS, CPUID_7_0_EBX_INVPCID, CPUID_7_0_EBX_RTM,
           CPUID_7_0_EBX_RDSEED */
 #define TCG_APM_FEATURES 0
+#define TCG_6_EAX_FEATURES CPUID_6_EAX_ARAT
 
 
 typedef struct FeatureWordInfo {
@@ -408,6 +420,11 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
         .cpuid_reg = R_EAX,
         .tcg_features = 0,
     },
+    [FEAT_6_EAX] = {
+        .feat_names = cpuid_6_feature_name,
+        .cpuid_eax = 6, .cpuid_reg = R_EAX,
+        .tcg_features = TCG_6_EAX_FEATURES,
+    },
 };
 
 typedef struct X86RegisterInfo32 {
@@ -1001,6 +1018,8 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_EXT2_LM | CPUID_EXT2_SYSCALL | CPUID_EXT2_NX,
         .features[FEAT_8000_0001_ECX] =
             CPUID_EXT3_LAHF_LM,
+        .features[FEAT_6_EAX] =
+            CPUID_6_EAX_ARAT,
         .xlevel = 0x8000000A,
         .model_id = "Westmere E56xx/L56xx/X56xx (Nehalem-C)",
     },
@@ -1030,6 +1049,8 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_EXT3_LAHF_LM,
         .features[FEAT_XSAVE] =
             CPUID_XSAVE_XSAVEOPT,
+        .features[FEAT_6_EAX] =
+            CPUID_6_EAX_ARAT,
         .xlevel = 0x8000000A,
         .model_id = "Intel Xeon E312xx (Sandy Bridge)",
     },
@@ -1062,6 +1083,8 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_EXT3_LAHF_LM,
         .features[FEAT_XSAVE] =
             CPUID_XSAVE_XSAVEOPT,
+        .features[FEAT_6_EAX] =
+            CPUID_6_EAX_ARAT,
         .xlevel = 0x8000000A,
         .model_id = "Intel Xeon E3-12xx v2 (Ivy Bridge)",
     },
@@ -1096,6 +1119,8 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_7_0_EBX_BMI2 | CPUID_7_0_EBX_ERMS | CPUID_7_0_EBX_INVPCID,
         .features[FEAT_XSAVE] =
             CPUID_XSAVE_XSAVEOPT,
+        .features[FEAT_6_EAX] =
+            CPUID_6_EAX_ARAT,
         .xlevel = 0x8000000A,
         .model_id = "Intel Core Processor (Haswell, no TSX)",
     },    {
@@ -1130,6 +1155,8 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_7_0_EBX_RTM,
         .features[FEAT_XSAVE] =
             CPUID_XSAVE_XSAVEOPT,
+        .features[FEAT_6_EAX] =
+            CPUID_6_EAX_ARAT,
         .xlevel = 0x8000000A,
         .model_id = "Intel Core Processor (Haswell)",
     },
@@ -1166,6 +1193,8 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_7_0_EBX_SMAP,
         .features[FEAT_XSAVE] =
             CPUID_XSAVE_XSAVEOPT,
+        .features[FEAT_6_EAX] =
+            CPUID_6_EAX_ARAT,
         .xlevel = 0x8000000A,
         .model_id = "Intel Core Processor (Broadwell, no TSX)",
     },
@@ -1202,6 +1231,8 @@ static X86CPUDefinition builtin_x86_defs[] = {
             CPUID_7_0_EBX_SMAP,
         .features[FEAT_XSAVE] =
             CPUID_XSAVE_XSAVEOPT,
+        .features[FEAT_6_EAX] =
+            CPUID_6_EAX_ARAT,
         .xlevel = 0x8000000A,
         .model_id = "Intel Core Processor (Broadwell)",
     },
@@ -2358,7 +2389,7 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, 
uint32_t count,
         break;
     case 6:
         /* Thermal and Power Leaf */
-        *eax = 0;
+        *eax = env->features[FEAT_6_EAX];
         *ebx = 0;
         *ecx = 0;
         *edx = 0;
diff --git a/target-i386/cpu.h b/target-i386/cpu.h
index 4ee12ca..800158e 100644
--- a/target-i386/cpu.h
+++ b/target-i386/cpu.h
@@ -412,6 +412,7 @@ typedef enum FeatureWord {
     FEAT_KVM,           /* CPUID[4000_0001].EAX (KVM_CPUID_FEATURES) */
     FEAT_SVM,           /* CPUID[8000_000A].EDX */
     FEAT_XSAVE,         /* CPUID[EAX=0xd,ECX=1].EAX */
+    FEAT_6_EAX,         /* CPUID[6].EAX */
     FEATURE_WORDS,
 } FeatureWord;
 
@@ -577,6 +578,8 @@ typedef uint32_t FeatureWordArray[FEATURE_WORDS];
 #define CPUID_XSAVE_XGETBV1    (1U << 2)
 #define CPUID_XSAVE_XSAVES     (1U << 3)
 
+#define CPUID_6_EAX_ARAT       (1U << 2)
+
 /* CPUID[0x80000007].EDX flags: */
 #define CPUID_APM_INVTSC       (1U << 8)
 
diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index a26d25a..b786359 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -233,6 +233,8 @@ uint32_t kvm_arch_get_supported_cpuid(KVMState *s, uint32_t 
function,
         if (!kvm_irqchip_in_kernel()) {
             ret &= ~CPUID_EXT_X2APIC;
         }
+    } else if (function == 6 && reg == R_EAX) {
+        ret |= CPUID_6_EAX_ARAT; /* safe to allow because of emulated APIC */
     } else if (function == 0x80000001 && reg == R_EDX) {
         /* On Intel, kvm returns cpuid according to the Intel spec,
          * so add missing bits according to the AMD spec:
-- 
2.1.4

Attachment: signature.asc
Description: OpenPGP digital signature


reply via email to

[Prev in Thread] Current Thread [Next in Thread]