Am 04.03.2012 21:59, schrieb Alexander Graf: > > > 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. :) > > [...] 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.
Err, 1k <= 4k would still be supported. The way I see it, the only cases breaking would be ppc with host page size < 4k, and ppcemb with host page size < 1k (which I'm not aware of). Is it realistic to expect virtualizing a Mac or pSeries to work on a 1k/2k bamboo? TCG would be unaffected AFAICT. Andreas -- SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg, Germany GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer; HRB 16746 AG Nürnberg