Hi, On 2/13/24 13:00, Michael S. Tsirkin wrote: > On Tue, Feb 13, 2024 at 12:24:22PM +0100, Eric Auger wrote: >> Hi Michael, >> On 2/13/24 12:09, Michael S. Tsirkin wrote: >>> On Tue, Feb 13, 2024 at 11:32:13AM +0100, Eric Auger wrote: >>>> Do you have an other concern? >>> I also worry a bit about migrating between hosts with different >>> page sizes. Not with kvm I am guessing but with tcg it does work I think? >> I have never tried but is it a valid use case? Adding Peter in CC. >>> Is this just for vfio and vdpa? Can we limit this to these setups >>> maybe? >> I am afraid we know the actual use case too later. If the VFIO device is >> hotplugged we have started working with 4kB granule. >> >> The other way is to introduce a min_granule option as done for aw-bits. >> But it is heavier. >> >> Thanks >> >> Eric > Let's say, if you are changing the default then we definitely want > a way to get the cmpatible behaviour for tcg. > So the compat machinery should be user-accessible too and documented.
I guess I need to add a new option to guarantee the machine compat. I was thinking about an enum GranuleMode property taking the following values, 4KB, 64KB, host Jean, do you think there is a rationale offering something richer? Obviously being able to set the exact page_size_mask + host mode would be better but this does not really fit into any std property type. Thanks Eric >
