x86/ldt: Fix small LDT allocation for Xen
x86/ldt: Fix small LDT allocation for Xen

While the following commit:

  37868fe113 ("x86/ldt: Make modify_ldt synchronous")

added a nice comment explaining that Xen needs page-aligned
whole page chunks for guest descriptor tables, it then
nevertheless used kzalloc() on the small size path.

As I'm unaware of guarantees for kmalloc(PAGE_SIZE, ) to return
page-aligned memory blocks, I believe this needs to be switched
back to __get_free_page() (or better get_zeroed_page()).

Signed-off-by: Jan Beulich <01de09643e0ae62e116f8bd77de435799874b456@suse.com>
Cc: Andy Lutomirski <2cc0d0d76de2e6f37b92deeb83c85cb306fc5dc1@amacapital.net>
Cc: Andy Lutomirski <2cc0d0d76de2e6f37b92deeb83c85cb306fc5dc1@kernel.org>
Cc: Boris Ostrovsky <b41c17b861974b03cec38e3ec2992769b9bfae55@oracle.com>
Cc: Borislav Petkov <0691a664b24b6f15b20cd5aee64b72271db08be1@alien8.de>
Cc: Brian Gerst <e60badcb99f652a0bcc15460d39f7ea12d6655ee@gmail.com>
Cc: David Vrabel <b9d45bd1f671e508cd8daa63dfc3cabb597562df@citrix.com>
Cc: Denys Vlasenko <50fbbd36fe0f9c8261d4a3c762c8c29ffb35e48f@redhat.com>
Cc: H. Peter Anvin <8a453bad9912ffe59bc0f0b8abe03df9be19379e@zytor.com>
Cc: Konrad Rzeszutek Wilk <da3a51b335cef0eb0e2c329c5ef6bcd6acef687a@oracle.com>
Cc: Linus Torvalds <69652caca27c8b940640ad396ab71f93cacec34f@linux-foundation.org>
Cc: Peter Zijlstra <3fddac958924aef220f202ca567388ddab3f14a8@infradead.org>
Cc: Thomas Gleixner <00e4cf8f46a57000a44449bf9dd8cbbcc209fd2a@linutronix.de>
Link: c2c3f58512c5a4e66c619a1ed59a5fa0b57fcfef@prv-mh.provo.novell.com
Signed-off-by: Ingo Molnar <9dbbbf0688fedc85ad4da37637f1a64b8c718ee2@kernel.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs