[Qemu-devel] [PATCH 0/2] Initial TSC-Scaling support for uq/master

[Qemu-devel] [PATCH 0/2] Initial TSC-Scaling support for uq/master

[Joerg Roedel]

Hi,

these two patches implement initial tsc-scaling support for qemu. The
TSC frequency for the guest can be configured with -cpu ,tsc_khz=x. If
supported by the kernel module qemu will pass the frequency to KVM. The
patches apply against current uq/master branch.

Regards,

	Joerg

Diffstat:

 target-i386/cpu.h   |    1 +
 target-i386/cpuid.c |   10 ++++++++++
 target-i386/kvm.c   |   11 +++++++++++
 3 files changed, 22 insertions(+), 0 deletions(-)

Shortlog:

Joerg Roedel (2):
      qemu-x86: Add tsc_khz option to -cpu
      qemu-x86: Set tsc_khz in kvm when supported

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

[Joerg Roedel]

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

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
 target-i386/cpu.h   |    1 +
 target-i386/cpuid.c |   10 ++++++++++
 2 files changed, 11 insertions(+), 0 deletions(-)

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;
-- 
1.7.4.1

[Qemu-devel] [PATCH 2/2] qemu-x86: Set tsc_khz in kvm when supported

[Joerg Roedel]

Make use of the KVM_TSC_CONTROL feature if available.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
 target-i386/kvm.c |   11 +++++++++++
 1 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index 1ae2d61..2d89544 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -528,6 +528,17 @@ int kvm_arch_init_vcpu(CPUState *env)
     }
 #endif
 
+#ifdef KVM_CAP_TSC_CONTROL
+    r = kvm_check_extension(env->kvm_state, KVM_CAP_TSC_CONTROL);
+    if (r && env->tsc_khz) {
+        r = kvm_vcpu_ioctl(env, KVM_SET_TSC_KHZ, env->tsc_khz);
+        if (r < 0) {
+            fprintf(stderr, "KVM_SET_TSC_KHZ failed\n");
+            return r;
+        }
+    }
+#endif
+
     qemu_add_vm_change_state_handler(cpu_update_state, env);
 
     return kvm_vcpu_ioctl(env, KVM_SET_CPUID2, &cpuid_data);
-- 
1.7.4.1

Re: [Qemu-devel] [PATCH 1/2] qemu-x86: Add tsc_khz option to -cpu

[Avi Kivity]

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).

-- 
error compiling committee.c: too many arguments to function