>>> On 29.02.16 at 16:10, <konrad.w...@oracle.com> wrote: > On Mon, Feb 29, 2016 at 11:28:49AM +0100, Olaf Hering wrote: >> What is the correct way to identify a Xen PV domU in the kenrel? >> devmem_is_allowed() used to disable access to pages < 256 in domU. >> With pvops this check was removed, or never ported forward. > > CC-ing Boris and Daniel. > > Why is this needed? The first 640KB of memory in a guest are > RAM pages with no BIOS data in it.
Exactly: devmem_is_allowed() is specifically meant to return true if and only if the page is not RAM or otherwise special. The question just is whether what Olaf suggested is also correct for Dom0 - I don't recall whether the low 1Mb gets 1:1 mapped in that case. Jan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel