On Fri, Aug 29, 2014 at 03:44:06PM +0100, Jan Beulich wrote: > >>> On 29.08.14 at 16:27, <stefan.ba...@canonical.com> wrote: > > Sure. Btw, someone also contacted me saying they have the same problem > > without > > changing the layout but having really big initrd (500M). While that feels > > like > > it should be impossible (if the kernel+initrd+xen stuff has to fix the 512M > > kernel image size area then). But if it can happen, then surely it does > > cause > > mappings to be where the module space starts then. > > Since the initrd doesn't really need to be mapped into the (limited) > virtual address space a pv guest starts with, we specifically got > > /* > * Whether or not the guest can deal with being passed an initrd not > * mapped through its initial page tables. > */ > #define XEN_ELFNOTE_MOD_START_PFN 16 > > to deal with that situation. The hypervisor side for Dom0 is in place, > and the kernel side works in our (classic) kernels. Whether it got > implemented for DomU meanwhile I don't know; I'm pretty certain > pv-ops kernels don't support it so far.
Correct - Not implemented. Here is what I had mentioned in the past: (see http://lists.xen.org/archives/html/xen-devel/2014-03/msg00580.html) XEN_ELFNOTE_INIT_P2M, XEN_ELFNOTE_MOD_START_PFN - I had been looking at that but I can't figure out a nice way of implementing this without the usage of SPARSEMAP_VMAP virtual addresses - which is how the classic Xen does it. But then - I don't know who is using huge PV guests - as the PVHVM does a fine job? But then with PVH, now you can boot with large amount of memory (1TB?) - so some of these issues would go away? Except the 'large ramdisk' as that would eat in the MODULES_VADDR I think? Needs more thinking. .. and then I left it and to my suprise saw on Luis's slides that Jurgen is going to take a look at that (500GB support). > > Jan > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
