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authorHaozhong Zhang <haozhong.zhang@intel.com>2015-11-24 11:33:55 +0800
committerEduardo Habkost <ehabkost@redhat.com>2016-01-21 12:47:16 -0200
commitbcffbeeb82302eaec6aa19e40c05ff3cc863c9f4 (patch)
tree65f9fa6dfdaeb14b9375e231cb333057975b38f0
parentf23a9db6bca5b9a228c77bbcaa06d01510e148b7 (diff)
target-i386: Fallback vcpu's TSC rate to value returned by KVM
If no user-specified TSC rate is present, we will try to set env->tsc_khz to the value returned by KVM_GET_TSC_KHZ. This patch does not change the current functionality of QEMU and just prepares for later patches to enable migrating vcpu's TSC rate. Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com> Reviewed-by: Eduardo Habkost <ehabkost@redhat.com> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
-rw-r--r--target-i386/kvm.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index 0551a5c27e..1212b507e7 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -868,6 +868,20 @@ int kvm_arch_init_vcpu(CPUState *cs)
}
}
+ /* vcpu's TSC frequency is either specified by user, or following
+ * the value used by KVM if the former is not present. In the
+ * latter case, we query it from KVM and record in env->tsc_khz,
+ * so that vcpu's TSC frequency can be migrated later via this field.
+ */
+ if (!env->tsc_khz) {
+ r = kvm_check_extension(cs->kvm_state, KVM_CAP_GET_TSC_KHZ) ?
+ kvm_vcpu_ioctl(cs, KVM_GET_TSC_KHZ) :
+ -ENOTSUP;
+ if (r > 0) {
+ env->tsc_khz = r;
+ }
+ }
+
if (has_xsave) {
env->kvm_xsave_buf = qemu_memalign(4096, sizeof(struct kvm_xsave));
}