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[Qemu-devel] [PATCH v6 1/3] target-i386: fallback vcpu's TSC rate to val
From: |
Haozhong Zhang |
Subject: |
[Qemu-devel] [PATCH v6 1/3] target-i386: fallback vcpu's TSC rate to value returned by KVM |
Date: |
Tue, 24 Nov 2015 11:33:55 +0800 |
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 <address@hidden>
---
target-i386/kvm.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index 2a9953b..a0fe9d4 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -832,6 +832,20 @@ 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));
}
--
2.4.8