On Tue, Mar 28, 2017 at 05:30:24PM +0200, Juergen Gross wrote: > On 28/03/17 16:27, Boris Ostrovsky wrote: > > On 03/28/2017 04:08 AM, Jan Beulich wrote: > >>>>> On 28.03.17 at 03:57, <boris.ostrov...@oracle.com> wrote: > >>> I think there is indeed a disconnect between target memory (provided by > >>> the toolstack) and current memory (i.e actual pages available to the > >>> guest). > >>> > >>> For example > >>> > >>> [ 0.000000] BIOS-e820: [mem 0x000000000009e000-0x000000000009ffff] > >>> reserved > >>> [ 0.000000] BIOS-e820: [mem 0x00000000000e0000-0x00000000000fffff] > >>> reserved > >>> > >>> are missed in target calculation. The hvmloader marks them as RESERVED > >>> (in build_e820_table()) but target value is not aware of this action. > >>> > >>> And then the same problem repeats when kernel removes > >>> 0x000a0000-0x000fffff chunk. > >> But this is all in-guest behavior, i.e. nothing an entity outside the > >> guest (tool stack or hypervisor) should need to be aware of. That > >> said, there is still room for improvement in the tools I think: > >> Regions which architecturally aren't RAM (namely the > >> 0xa0000-0xfffff range) would probably better not be accounted > >> for as RAM as far as ballooning is concerned. In the hypervisor, > >> otoh, all memory assigned to the guest (i.e. including such backing > >> ROMs) needs to be accounted. > > > > On the Linux side we should not include in balloon calculations pages > > reserved by trim_bios_range(), i.e. (BIOS_END-BIOS_BEGIN) + 1. > > > > Which leaves hvmloader's special pages (and possibly memory under > > 0xA0000 which may get reserved). Can we pass this info to guests via > > xenstore? > > I'd rather keep an internal difference between online pages and E820-map > count value in the balloon driver. This should work always.
Did we ever come with a patch for this? _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org https://lists.xen.org/xen-devel