From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [PATCH 2/2] KVM: x86: allow BSP to handle INIT IPIs like APs do Date: Mon, 8 Feb 2016 18:44:09 +0100 Message-ID: <56B8D3E9.1020400@redhat.com> References: <1454539876-8310-1-git-send-email-brogers@suse.com> <1454539876-8310-2-git-send-email-brogers@suse.com> <56B8B057.5050900@redhat.com> <56B8B29C.8060600@web.de> <56B860E202000048001251D8@prv-mh.provo.novell.com> <56B8C51A.2070505@redhat.com> <56B86D9B02000048001251EF@prv-mh.provo.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: namit@cs.technion.ac.il To: Bruce Rogers , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Jan Kiszka Return-path: In-Reply-To: <56B86D9B02000048001251EF@prv-mh.provo.novell.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 08/02/2016 18:27, Bruce Rogers wrote: > I had read that, but I though this was speaking from the perspective of the > SMP aware BIOS code only. It says "logical processor", so I cannot really see how it can be interpreted that way. The BSP jumps to 0xFFFFFFF0, the APs go into wait-for-SIPI state. > I certainly could be wrong about my above interpretation, but with these > changes I'm proposing, things work well for the test case of manually onlining > the BSP after the crash kernel has been started (via kexec -e on a AP processor > with maxcpus=1 on the crash kernel command line). From looking through the > kernel git history it appears this sequence of events was explicitly supported > quite a while ago, and we've got a customer who uses this for fast recovery from > a guest kernel crash. You need to comment on the output of trace-cmd for KVM events, or provide a full reproducer, or at the very least point me to the kernel code that you're referring to. Otherwise I just cannot understand what you're talking about; sorry. :( Paolo