Re: [Xen-devel] [PATCH] VTd/dmar: Tweak how the DMAR table is clobbered

2015-04-17 Thread Jan Beulich
On 16.04.15 at 18:44, kevin.t...@intel.com wrote: From: Andrew Cooper [mailto:andrew.coop...@citrix.com] Sent: Tuesday, April 14, 2015 5:09 PM On 14/04/15 08:50, Jan Beulich wrote: Unless Kevin or Yang object, I'd therefore suggest reverting the change. Once we determined why VT-d needs

Re: [Xen-devel] [PATCH] VTd/dmar: Tweak how the DMAR table is clobbered

2015-04-14 Thread Jan Beulich
On 10.04.15 at 11:08, andrew.coop...@citrix.com wrote: On 10/04/15 02:23, Tian, Kevin wrote: From: Andrew Cooper [mailto:andrew.coop...@citrix.com] Sent: Thursday, April 09, 2015 3:45 AM Intead of clobbering DMAR - XMAR and back, clobber to RMAD instead. This means that changing the

Re: [Xen-devel] [PATCH] VTd/dmar: Tweak how the DMAR table is clobbered

2015-04-14 Thread Andrew Cooper
On 14/04/15 08:50, Jan Beulich wrote: On 10.04.15 at 11:08, andrew.coop...@citrix.com wrote: On 10/04/15 02:23, Tian, Kevin wrote: From: Andrew Cooper [mailto:andrew.coop...@citrix.com] Sent: Thursday, April 09, 2015 3:45 AM Intead of clobbering DMAR - XMAR and back, clobber to RMAD instead.

Re: [Xen-devel] [PATCH] VTd/dmar: Tweak how the DMAR table is clobbered

2015-04-09 Thread Andrew Cooper
On 09/04/15 09:51, David Vrabel wrote: On 08/04/15 20:44, Andrew Cooper wrote: Intead of clobbering DMAR - XMAR and back, clobber to RMAD instead. This means that changing the signature does not alter the checksum, which allows the clobbering/unclobbering to be peformed atomically and

Re: [Xen-devel] [PATCH] VTd/dmar: Tweak how the DMAR table is clobbered

2015-04-09 Thread David Vrabel
On 08/04/15 20:44, Andrew Cooper wrote: Intead of clobbering DMAR - XMAR and back, clobber to RMAD instead. This means that changing the signature does not alter the checksum, which allows the clobbering/unclobbering to be peformed atomically and idempotently, which is an advantage on the

[Xen-devel] [PATCH] VTd/dmar: Tweak how the DMAR table is clobbered

2015-04-08 Thread Andrew Cooper
Intead of clobbering DMAR - XMAR and back, clobber to RMAD instead. This means that changing the signature does not alter the checksum, which allows the clobbering/unclobbering to be peformed atomically and idempotently, which is an advantage on the kexec path which can reenter