On 04.03.2012, at 21:31, Andreas Färber <afaer...@suse.de> wrote:
> Am 04.03.2012 21:25, schrieb Alexander Graf: >> >> >> On 04.03.2012, at 21:21, Andreas Färber <afaer...@suse.de> wrote: >> >>> Am 04.03.2012 19:46, schrieb Alexander Graf: >>>> >>>> >>>> On 04.03.2012, at 17:46, Andreas Färber <afaer...@suse.de> wrote: >>>> >>>>> Am 04.03.2012 12:53, schrieb Benjamin Herrenschmidt: >>>>>> On Sun, 2012-03-04 at 12:49 +0200, Avi Kivity wrote: >>>>>>> On 02/28/2012 11:48 PM, Benjamin Herrenschmidt wrote: >>>>>>>> On Tue, 2012-02-28 at 14:32 +0200, Avi Kivity wrote: >>>>>>>> >>>>>>>>> What if TARGET_PAGE_SIZE > getpagesize()? Or is that impossible? >>>>>>>> >>>>>>>> We have yet to encounter such a case. It's not currently possible on >>>>>>>> power (some old embedded chips could do 1K and 2K page sizes in the TLB >>>>>>>> iirc but we never supported that in Linux and it's being phased out in >>>>>>>> HW). >>>>>>>> >>>>>>>> I suggest that gets dealt with when/if it needs to, which means >>>>>>>> probably >>>>>>>> never :-) >>>>>>> >>>>>>> Doesn't ppc support both 4k and 64k pages? Suppose you run a 4k guest >>>>>>> on a 64k host? >>>>>>> >>>>>>> Maybe I'm misremembering or misunderstanding something. >>>>> >>>>>> TARGET_PAGE_SIZE in qemu is always 4k for powerpc, it's a compile time >>>>>> #define. >>>>> >>>>> Except for ppcemb-softmmu (1k), which is irrelevant for KVM AFAIU. >>>>> >>>>> Maybe just add an assert and be done with it? >>>> >>>> Assert for what? Linux page size of 64k is something perfectly normal on >>>> ppc. The hardware can always do at least 4k maps however. >>> >>> g_assert(TARGET_PAGE_SIZE <= getpagesize()) >>> >>> Just declare the above case as unsupported and abort if we encounter it. >> >> What I'm trying to tell you is that it's the default case on book3s ppc! ;) > > Exactly, which is why I'm saying just ignore the weird embedded case. :) Ugh. Sorry, apparently I can't read :). So you're saying 'break for ppcemb'. Hrm. Not sure that'd be all that great for 440, since there host pagesize is still 4k, but T_P_S is 1k. Alex > > Andreas > > -- > SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany > GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg