>>> On 08.01.18 at 11:37, <roger....@citrix.com> wrote: > On Mon, Jan 08, 2018 at 03:30:17AM -0700, Jan Beulich wrote: >> >>> On 04.01.18 at 14:05, <wei.l...@citrix.com> wrote: >> > @@ -288,8 +289,12 @@ void __init arch_init_memory(void) >> > dom_cow = domain_create(DOMID_COW, DOMCRF_dummy, 0, NULL); >> > BUG_ON(IS_ERR(dom_cow)); >> > >> > - /* First 1MB of RAM is historically marked as I/O. */ >> > - for ( i = 0; i < 0x100; i++ ) >> > + /* >> > + * First 1MB of RAM is historically marked as I/O. If we booted PVH, >> > + * reclaim the space. Irrespective, leave MFN 0 as special for the >> > sake >> > + * of 0 being a very common default value. >> > + */ >> > + for ( i = 0; i < (pvh_boot ? 1 : 0x100); i++ ) >> > share_xen_page_with_guest(mfn_to_page(_mfn(i)), >> > dom_io, XENSHARE_writable); >> >> I can see this being valid as long as there's no firmware. What >> doesn't become clear from neither the description nor the >> comment is whether this is a necessary change, or just an >> optimization to avoid wasting these 255 pages. > > It's just an optimization to not waste the low 1MiB. The shim will > work equally well without this.
Good. Please say so in the description. Jan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
