From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cooper Subject: [PATCH RFC 0/2] Fix RTC noack issues Date: Tue, 26 Nov 2013 20:39:16 +0000 Message-ID: <1385498358-10077-1-git-send-email-andrew.cooper3@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Xen-devel Cc: Andrew Cooper List-Id: xen-devel@lists.xenproject.org This series allows the toolstack to choose (by way of XenStore platform flags) whether the domain is expecting to make use of RTC mode noack performance optimisations. It also switches the implict default back to rtc_mode_strict, which is the safe default for Xen to have. This fixes a longstanding regression in Win2k3SP2 only where its access pattern causes it to fall into an infinite loop reading RTC RegC. Questions for thought: * Does it make sense to allow customisation of ACPI_WAET_TIMER_ONE_READ ? There is no sitation where an admin should turn it off. * I believe this is safe wrt migrations, but am not certain enough to say for sure. This is a critical point, as the bad default (and regression) has been in Xen since late in the Xen-4.3 development cycle. -- 1.7.10.4