On 12/06/2017 03:19 PM, Julien Grall wrote: > Hi Konrad, > > On 12/06/2017 03:10 PM, Konrad Rzeszutek Wilk wrote: >> .snip.. >>> The suggested policy is based on the KVM one: >>> - If we trap a S/W instructions, we enable VM trapping (e.g >>> HCR_EL2.TVM) to >>> detect cache being turned on/off, and do a full clean. >>> - We flush the caches on both caches being turned on and off. >>> - Once the caches are enabled, we stop trapping VM instructions. >>> >>> Doing a full clean will require to go through the P2M and flush the >>> entries >>> one by one. At the moment, all the memory is mapped. As you can imagine >>> flushing guest with hundreds of MB will take a very long time (Linux >>> timeout >>> during CPU bring). >> >> Yikes. Since you mention 'based on the KVM one' - did they solve this >> particular >> problem or do they also have the same issue? > > KVM is using populate on demand by default.
If I understand properly, it's probably more accurate to say that KVM uses "allocate on demand". The complicated part of populate-on-demand is the fact that it's not allowed to allocate anything. -George _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
