Re: [RFC PATCH V2] kvm: x86: reduce rtc 0x70 access vm-exit time

2017-08-14 Thread Paolo Bonzini
On 13/08/2017 21:51, Peng Hao wrote: > some versions of windows guest access rtc frequently because of > rtc as system tick.guest access rtc like this: write register index > to 0x70, then write or read data from 0x71. writing 0x70 port is > just as index and do nothing else. So we can use coalesce

[RFC PATCH V2] kvm: x86: reduce rtc 0x70 access vm-exit time

2017-08-13 Thread Peng Hao
some versions of windows guest access rtc frequently because of rtc as system tick.guest access rtc like this: write register index to 0x70, then write or read data from 0x71. writing 0x70 port is just as index and do nothing else. So we can use coalesced mmio to handle this scene to reduce VM-EXIT