RE: [Xen-devel] How to determine memory size in HVM

["James Harper" <james.harper@xxxxxxxxxxxxxxxx>]

> 
> Hypercall XENMEM_current_reservation.
> 
> *But* be aware I'm not sure how that interacts with e.g., virtual
> framebuffer memory. Well, actually I know it will include the virtual
> framebuffer memory which is not actually really part of normal guest
RAM.
> The question will be: does the xenstore 'target' value also include
it? I
> guess you'll have to compare to create a HVM guest and compare the two
to
> decide.

Thanks for that.

Another question, if I do 'xm mem-set' (without any handling of the
memory/target value) and then reboot, the system reboots with the new
target memory value, making it impossible to add memory to the system
again (under Windows at least). The only way I can think of fixing that
is to write back to memory/target with the original value just before
rebooting, but even that could be prone to errors in case of an unclean
reboot or something... any way around this?

James


> 
>  -- Keir
> 
> On 08/06/2009 15:12, "James Harper" <james.harper@xxxxxxxxxxxxxxxx>
wrote:
> 
> > How can I tell how much memory my VM has under HVM? I want to have
> > something concrete to compare the 'target' value in xenstore to for
> > ballooning so I am reluctant to ask Windows the question. There
seems to
> > be a nr_pages in start_info, but HVM doesn't have that...
> >
> > My reason for not wanting to ask Windows how much memory is that if
it
> > says we have 3.5G (reasonable without PAE) and xenstore says we have
4G
> > then I'm going to have to fudge things a bit to know whether we are
> > ballooning up or down etc.
> >
> > I could just read the initial target value from xenstore on boot,
but
> > even that could be changed before my drivers get to it.
> >
> > Thanks
> >
> > James
> >
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@xxxxxxxxxxxxxxxxxxx
> > http://lists.xensource.com/xen-devel
> 


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