From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cooper Subject: [PATCH 0 of 1] Kexec alteration Date: Thu, 6 Dec 2012 15:56:22 +0000 Message-ID: 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@lists.xen.org Cc: Andrew Cooper List-Id: xen-devel@lists.xenproject.org Hello, Fixing the root reentrant NMI/MCE issues is quickly turning into a substantially larger problem than initially thought. As a result, I have decided to submit the fixes in smaller chunks, in the hope that they are reviewed and integrated separately. The first part is changes to the kexec path, from which I am now happy to drop the RFC tag. Please scrutinise carefully. The vague decided plan going forwards is: * Implement spin_{un,}lock_recursive_irq{save,restore}() * Audit users of mixed regular/recursive calls on the same spinlock * Swap recursive spinlocks to be a separate type * Fix the semantics of console_force_unlock * Continue audit of NMI and MCE paths, with console semantics fixed * {Panic,NMI,MCE}-in-progress flags & reentrancy protection * Ability to specify whether iret should be used on trap exit * Implement "MCEs never iret, NMIs always iret" policy The plan for "things I think needs to happen" is: * Extend spinlock debugging to know about NMI and MCE contexts * Implement strict ordering constraints for spinlock debugging The "other things needing investigating" list includes: * Interaction of paging changes and IDTs while purgatory is changing processor modes ~Andrew