forward cpuid leaves when using -cpu host

PATCH Superseded Benoît Canet 1 participant 2 messages Aug 27, 2013

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Benoît Canet

author

2013-08-27 21:04 UTC #0 lore raw

PATCH v2 1/1 forward cpuid leaves when using -cpu host

This patch uses directly cpuid_host to forward the informations instead of storing a variable number of leaves in the cpu states.

since v1:
use index as argument to cpuid_host

Benoît Canet (1):
i386: forward CPUID cache leaves when -cpu host is used

 target-i386/cpu.c |   19 +++++++++++++++++++
 target-i386/cpu.h |    1 +
 2 files changed, 20 insertions(+)

Signature · 1 line

1.7.10.4

Benoît Canet

author

2013-08-27 21:04 UTC #1 lore raw

PATCH v2 1/1 i386: forward CPUID cache leaves when -cpu host is used

Some users running cpu intensive tasks checking the cache CPUID leaves at startup and making decisions based on the result reported that the guest was not reflecting the host CPUID leaves when -cpu host is used.

This patch fix this.

Signed-off-by Benoit Canet <[email protected]>

---
 target-i386/cpu.c |   19 +++++++++++++++++++
 target-i386/cpu.h |    1 +
 2 files changed, 20 insertions(+)

target-i386/cpu.c +19 -0

index 42c5de0..79bb012 100644
@@ -374,6 +374,7 @@ typedef struct x86_def_t {
     int stepping;
     FeatureWordArray features;
     char model_id[48];
+    bool fwd_cpuid_cache_leaves;
 } x86_def_t;
 
 #define I486_FEATURES (CPUID_FP87 | CPUID_VME | CPUID_PSE)

@@ -1027,6 +1028,7 @@ static void kvm_cpu_fill_host(x86_def_t *x86_cpu_def)
     assert(kvm_enabled());
 
     x86_cpu_def->name = "host";
+    x86_cpu_def->fwd_cpuid_cache_leaves = true;
     host_cpuid(0x0, 0, &eax, &ebx, &ecx, &edx);
     x86_cpu_vendor_words2str(x86_cpu_def->vendor, ebx, edx, ecx);

@@ -1776,6 +1778,7 @@ static void cpu_x86_register(X86CPU *cpu, const char *name, Error **errp)
     env->features[FEAT_C000_0001_EDX] = def->features[FEAT_C000_0001_EDX];
     env->features[FEAT_7_0_EBX] = def->features[FEAT_7_0_EBX];
     env->cpuid_xlevel2 = def->xlevel2;
+    env->fwd_cpuid_cache_leaves = def->fwd_cpuid_cache_leaves;
 
     object_property_set_str(OBJECT(cpu), def->model_id, "model-id", errp);
 }

@@ -1949,6 +1952,10 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
         }
         break;
     case 2:
+        if (env->fwd_cpuid_cache_leaves) {
+            host_cpuid(index, 0, eax, ebx, ecx, edx);
+            break;
+        }
         /* cache info: needed for Pentium Pro compatibility */
         *eax = 1;
         *ebx = 0;

@@ -1956,6 +1963,10 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
         *edx = 0x2c307d;
         break;
     case 4:
+        if (env->fwd_cpuid_cache_leaves) {
+            host_cpuid(index, count, eax, ebx, ecx, edx);
+            break;
+        }
         /* cache info: needed for Core compatibility */
         if (cs->nr_cores > 1) {
             *eax = (cs->nr_cores - 1) << 26;

@@ -2102,6 +2113,10 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
         break;
     case 0x80000005:
         /* cache info (L1 cache) */
+        if (env->fwd_cpuid_cache_leaves) {
+            host_cpuid(index, 0, eax, ebx, ecx, edx);
+            break;
+        }
         *eax = 0x01ff01ff;
         *ebx = 0x01ff01ff;
         *ecx = 0x40020140;

@@ -2109,6 +2124,10 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index, uint32_t count,
         break;
     case 0x80000006:
         /* cache info (L2 cache) */
+        if (env->fwd_cpuid_cache_leaves) {
+            host_cpuid(index, 0, eax, ebx, ecx, edx);
+            break;
+        }
         *eax = 0;
         *ebx = 0x42004200;
         *ecx = 0x02008140;

target-i386/cpu.h +1 -0

index 8a3d0fd..1ec32fa 100644
@@ -865,6 +865,7 @@ typedef struct CPUX86State {
     bool tsc_valid;
     int tsc_khz;
     void *kvm_xsave_buf;
+    bool fwd_cpuid_cache_leaves;
 
     /* in order to simplify APIC support, we leave this pointer to the
        user */

Signature · 1 line

1.7.10.4