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target-i386: Add support to migrate vcpu's TSC rate

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This patch enables migrating vcpu's TSC rate. If KVM on the
destination machine supports TSC scaling, guest programs will
observe a consistent TSC rate across the migration.

If TSC scaling is not supported on the destination machine, the
migration will not be aborted and QEMU on the destination will
not set vcpu's TSC rate to the migrated value.

If vcpu's TSC rate specified by CPU option 'tsc-freq' on the
destination machine is inconsistent with the migrated TSC rate,
the migration will be aborted.

For backwards compatibility, the migration of vcpu's TSC rate is
disabled on pc-*-2.5 and older machine types.

Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
[ehabkost: Rewrote comment at kvm_arch_put_registers()]
[ehabkost: Moved compat code to pc-2.5]
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
This commit is contained in:
Haozhong Zhang 2015-11-24 11:33:57 +08:00 • committed by Eduardo Habkost
parent 5031283d52
commit 36f96c4b6b
9 changed files with 50 additions and 2 deletions
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9
target-i386/kvm.c
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@ -2507,6 +2507,15 @@ int kvm_arch_put_registers(CPUState *cpu, int level)
}
}
if (level == KVM_PUT_FULL_STATE) {
/* We don't check for kvm_arch_set_tsc_khz() errors here,
* because TSC frequency mismatch shouldn't abort migration,
* unless the user explicitly asked for a more strict TSC
* setting (e.g. using an explicit "tsc-freq" option).
*/
kvm_arch_set_tsc_khz(cpu);
}
ret = kvm_getput_regs(x86_cpu, 1);
if (ret < 0) {
return ret;