On Mon, Mar 02, 2020 at 07:47:28PM +0800, Tao Xu wrote: > On 2/29/2020 5:39 AM, Eduardo Habkost wrote: > > On Wed, Feb 12, 2020 at 04:13:26PM +0800, Tao Xu wrote: > > > Add new version of Snowridge, Denverton, Opteron_G3, EPYC, and Dhyana > > > CPU model to uremove MONITOR/MWAIT featre. > > > > > > After QEMU/KVM use "-overcommit cpu-pm=on" to expose MONITOR/MWAIT > > > (commit id 6f131f13e68d648a8e4f083c667ab1acd88ce4cd), the MONITOR/MWAIT > > > feature in these CPU model is unused. > > > > > > Signed-off-by: Tao Xu <tao3...@intel.com> > > > > What exactly is the problem you are trying to fix? > > > > No CPU model will ever have monitor=on set by default with KVM, > > because kvm_default_props has a monitor=off element. > > > > Maybe it is not a fix. For example, when we boot a guest with Denverton > cpu model, guest cannot detect MONITOR/MWAIT and boot with no warning, > because of "monitor=off" by default. The MONITOR/MWAIT feature in these CPU > model is unused,but no harm. I am wondering if we should remove it from > existing CPU models.
As monitor=off is on kvm_default_props, changing the CPU model table will only affect other accelerators (e.g. TCG, where MONITOR/MWAIT support is advertised as supported). We shouldn't be dictating policy for other accelerators just because KVM doesn't support it. Removing the feature on kvm_default_props is sufficient. -- Eduardo
