[1/2] qemu-x86: Add tsc_khz option to -cpu

Commit Message

Joerg Roedel June 17, 2011, 2 p.m. UTC

To let the user configure the desired tsc frequency for the
guest if running in KVM.

Signed-off-by: Joerg Roedel <[e-mail]>
---
 target-i386/cpu.h   |    1 +
 target-i386/cpuid.c |   10 ++++++++++
 2 files changed, 11 insertions(+), 0 deletions(-)

Comments

Avi Kivity June 19, 2011, 11:32 a.m. UTC | #1

On 06/17/2011 05:00 PM, Joerg Roedel wrote:
> To let the user configure the desired tsc frequency for the
> guest if running in KVM.
>
> @@ -704,6 +705,14 @@ static int cpu_x86_find_by_name(x86_def_t *x86_cpu_def, const char *cpu_model)
>               } else if (!strcmp(featurestr, "model_id")) {
>                   pstrcpy(x86_cpu_def->model_id, sizeof(x86_cpu_def->model_id),
>                           val);
> +            } else if (!strcmp(featurestr, "tsc_khz")) {
> +                char *err;
> +                numvalue = strtoul(val,&err, 0);
> +                if (!*val || *err) {
> +                    fprintf(stderr, "bad numerical value %s\n", val);
> +                    goto error;
> +                }
> +                x86_cpu_def->tsc_khz = numvalue;
>               } else {
>                   fprintf(stderr, "unrecognized feature %s\n", featurestr);
>                   goto error;

Frequency should be in Hz, not kHz.  We can use [kMG] suffixes for 
simpler specification (but 1GHz = 10^9 Hz, not the binary thing).

Patch

diff --git a/target-i386/cpu.h b/target-i386/cpu.h
index 0b039d4..a381c34 100644
--- a/target-i386/cpu.h
+++ b/target-i386/cpu.h
@@ -753,6 +753,7 @@  typedef struct CPUX86State {
     uint32_t cpuid_kvm_features;
     uint32_t cpuid_svm_features;
     bool tsc_valid;
+    int tsc_khz;
     
     /* in order to simplify APIC support, we leave this pointer to the
        user */
diff --git a/target-i386/cpuid.c b/target-i386/cpuid.c
index 79e7580..2b59e66 100644
--- a/target-i386/cpuid.c
+++ b/target-i386/cpuid.c
@@ -224,6 +224,7 @@  typedef struct x86_def_t {
     int family;
     int model;
     int stepping;
+    int tsc_khz;
     uint32_t features, ext_features, ext2_features, ext3_features;
     uint32_t kvm_features, svm_features;
     uint32_t xlevel;
@@ -704,6 +705,14 @@  static int cpu_x86_find_by_name(x86_def_t *x86_cpu_def, const char *cpu_model)
             } else if (!strcmp(featurestr, "model_id")) {
                 pstrcpy(x86_cpu_def->model_id, sizeof(x86_cpu_def->model_id),
                         val);
+            } else if (!strcmp(featurestr, "tsc_khz")) {
+                char *err;
+                numvalue = strtoul(val, &err, 0);
+                if (!*val || *err) {
+                    fprintf(stderr, "bad numerical value %s\n", val);
+                    goto error;
+                }
+                x86_cpu_def->tsc_khz = numvalue;
             } else {
                 fprintf(stderr, "unrecognized feature %s\n", featurestr);
                 goto error;
@@ -872,6 +881,7 @@  int cpu_x86_register (CPUX86State *env, const char *cpu_model)
     env->cpuid_svm_features = def->svm_features;
     env->cpuid_ext4_features = def->ext4_features;
     env->cpuid_xlevel2 = def->xlevel2;
+    env->tsc_khz = def->tsc_khz;
     if (!kvm_enabled()) {
         env->cpuid_features &= TCG_FEATURES;
         env->cpuid_ext_features &= TCG_EXT_FEATURES;