Messages in this thread | | | From | Andy Lutomirski <> | Date | Tue, 1 Sep 2015 12:37:58 -0700 | Subject | Re: [PATCH] x86: fix small LDT allocation for Xen |
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On Tue, Sep 1, 2015 at 3:48 AM, Jan Beulich <JBeulich@suse.com> wrote: > While 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(). > > Signed-off-by: Jan Beulich <jbeulich@suse.com> > Cc: Andy Lutomirski <luto@kernel.org> > Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> > Cc: David Vrabel <david.vrabel@citrix.com> > Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> > --- > arch/x86/kernel/ldt.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > --- 4.2/arch/x86/kernel/ldt.c > +++ 4.2-x86-LDT-alloc/arch/x86/kernel/ldt.c > @@ -58,7 +58,7 @@ static struct ldt_struct *alloc_ldt_stru > if (alloc_size > PAGE_SIZE) > new_ldt->entries = vzalloc(alloc_size); > else > - new_ldt->entries = kzalloc(PAGE_SIZE, GFP_KERNEL); > + new_ldt->entries = (void *)__get_free_page(GFP_KERNEL|__GFP_ZERO);
This would need a corresponding change to the kfree path, right?
--Andy
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