On 17/04/2018 22:59, Eduardo Habkost wrote:
>> + if (disable_exits) {
>> + disable_exits &= (KVM_X86_DISABLE_EXITS_MWAIT |
>> + KVM_X86_DISABLE_EXITS_HLT |
>> + KVM_X86_DISABLE_EXITS_PAUSE);
>> + if (env->user_features[FEAT_KVM] & KVM_PV_UNHALT) {
>> + disable_exits &= ~KVM_X86_DISABLE_EXITS_HLT;
>> + }
>
> In the future, if we decide to enable kvm-pv-unhalt by default,
> should "-cpu ...,kvm-hint-dedicated=on" disable kvm-pv-unhalt
> automatically, or should we require an explicit
> "kvm-hint-dedicated=on,kvm-pv-unhalt=off" option?
It should be automatic.
> For today's defaults, this patch solves the problem, only one
> thing is missing before I give my R-b: we need to clearly
> document what exactly are the consequences and requirements of
> setting kvm-hint-dedicated=on (I'm not sure if the best place for
> this is qemu-options.hx, x86_cpu_list(), or somewhere else).
I don't think we have a good place for this kind of documentation,
unfortunately. Right now it is mentioned in
Documentation/virtual/kvm/cpuid.txt.
Paolo
