On 16/06/2016 12:29, Haozhong Zhang wrote:
> On 06/16/16 11:51, Paolo Bonzini wrote:
>>
>>
>> On 16/06/2016 08:06, Haozhong Zhang wrote:
>>> Migration is only allowed between VCPUs with the same lmce option.
>>>
>>> Signed-off-by: Haozhong Zhang <haozhong.zhang@xxxxxxxxx>
>>> ---
>>> target-i386/machine.c | 25 +++++++++++++++++++++++++
>>> 1 file changed, 25 insertions(+)
>>>
>>> diff --git a/target-i386/machine.c b/target-i386/machine.c
>>> index cb9adf2..00375a3 100644
>>> --- a/target-i386/machine.c
>>> +++ b/target-i386/machine.c
>>> @@ -347,6 +347,12 @@ static int cpu_post_load(void *opaque, int version_id)
>>> return -EINVAL;
>>> }
>>>
>>> + if (!cpu->enable_lmce && (env->mcg_cap & MCG_LMCE_P)) {
>>> + error_report("Config mismatch: VCPU has LMCE enabled, "
>>> + "but \"lmce\" option is disabled");
>>> + return -EINVAL;
>>> + }
>>> +
>>
>> I think this is unnecessary. Apart from this, the patch is good and can
>> be squashed in patch 1 for v5.
>>
>
> Without this check, the migration from LMCE enabled QEMU to LMCE
> disabled QEMU will not fail. Is such configuration change considered
> be error? If not, I will remove the error report and return, but add a
> fix to remove MCG_LMCE_P from env->mcg_cap in this check.
It's considered a user error. You can skip the "if" completely.
Paolo
> Haozhong
>
>>
>>> /*
>>> * Real mode guest segments register DPL should be zero.
>>> * Older KVM version were setting it wrongly.
>>> @@ -896,6 +902,24 @@ static const VMStateDescription vmstate_tsc_khz = {
>>> }
>>> };
>>>
>>> +static bool mcg_ext_ctl_needed(void *opaque)
>>> +{
>>> + X86CPU *cpu = opaque;
>>> + CPUX86State *env = &cpu->env;
>>> + return cpu->enable_lmce && env->mcg_ext_ctl;
>>> +}
>>> +
>>> +static const VMStateDescription vmstate_mcg_ext_ctl = {
>>> + .name = "cpu/mcg_ext_ctl",
>>> + .version_id = 1,
>>> + .minimum_version_id = 1,
>>> + .needed = mcg_ext_ctl_needed,
>>> + .fields = (VMStateField[]) {
>>> + VMSTATE_UINT64(env.mcg_ext_ctl, X86CPU),
>>> + VMSTATE_END_OF_LIST()
>>> + }
>>> +};
>>> +
>>> VMStateDescription vmstate_x86_cpu = {
>>> .name = "cpu",
>>> .version_id = 12,
>>> @@ -1022,6 +1046,7 @@ VMStateDescription vmstate_x86_cpu = {
>>> #ifdef TARGET_X86_64
>>> &vmstate_pkru,
>>> #endif
>>> + &vmstate_mcg_ext_ctl,
>>> NULL
>>> }
>>> };
>>>
--
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