Re: [Xen-devel] xen: Fix possible page fault in fifo events

2014-07-15 Thread Frediano Ziglio
On Tue, 2014-07-15 at 15:32 +0100, Andrew Cooper wrote: > On 15/07/14 14:48, Frediano Ziglio wrote: > > sync_test_bit function require a long* read access to pointer. > > This is a problem if the you are using last entry in the page causing > > an access to next page. If this page is not readable y

Re: [Xen-devel] xen: Fix possible page fault in fifo events

2014-07-15 Thread Konrad Rzeszutek Wilk
On Tue, Jul 15, 2014 at 03:32:58PM +0100, Andrew Cooper wrote: > On 15/07/14 14:48, Frediano Ziglio wrote: > > sync_test_bit function require a long* read access to pointer. > > This is a problem if the you are using last entry in the page causing > > an access to next page. If this page is not rea

Re: [Xen-devel] xen: Fix possible page fault in fifo events

2014-07-15 Thread Andrew Cooper
On 15/07/14 14:48, Frediano Ziglio wrote: > sync_test_bit function require a long* read access to pointer. > This is a problem if the you are using last entry in the page causing > an access to next page. If this page is not readable you get a memory > access failure (page fault). > All other x64 b