In message <gv5748$usq$1@xxxxxx-september.org> VanguardLH
<V@xxxxxx> was claimed to have wrote:
Quote:
>kellyapproved@xxxxxx wrote:
> Quote:
>> When you setup a guest OS, you need to allocate RAM to it.
>>
>> Let's say you have a host with 3 GB of RAM with two guests, each of
>> which you allocate 1 GB of RAM.
>>
>> If both guests are in use, the host and two guests will get 1 GB of
>> RAM each.
>>
>> Is there a way to set it so that if only 1 guest is in use, it can
>> draw on the spare RAM that is allocated to the other guest that is not
>> used.
>
>If one VM could monitor the memory usage of another VM to see what
>blocks were unallocated, you just threw out the isolation that
>virtualization is supposed to afford for security. With all due respect, that isn't true at all. VMWare allows RAM to be
over-allocated, which would be the first step to implementing this
request.
To avoid the performance implications of over-utilizing RAM, a second
step would be to have the integration components/additions/tools report
back the amount of available RAM within each VM to the host, and the
host would reply back telling the additions to allocate or release RAM
within each guest, tricking the guest into not using certain amounts of
RAM to make that RAM available to the host (and therefore, for
allocation to other VMs)
Guests already communicate with hosts in a number of ways, adding a
counters for available RAM, available clean pages, cache sizes and an
API to the guest components wouldn't cause any sort of security issue if
implemented properly.