From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 2/4] KVM: Rework VCPU state writeback API Date: Thu, 11 Mar 2010 10:32:50 +0200 Message-ID: <4B98AAB2.7020202@redhat.com> References: <2257cac7474705fc35d74fcdff0566fb7dc0770e.1267467030.git.jan.kiszka@siemens.com> <20100302001415.GA22627@amt.cnet> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Jan Kiszka , kvm@vger.kernel.org, qemu-devel@nongnu.org To: Marcelo Tosatti Return-path: Received: from mx1.redhat.com ([209.132.183.28]:48230 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753765Ab0CKIcz (ORCPT ); Thu, 11 Mar 2010 03:32:55 -0500 In-Reply-To: <20100302001415.GA22627@amt.cnet> Sender: kvm-owner@vger.kernel.org List-ID: On 03/02/2010 02:14 AM, Marcelo Tosatti wrote: > On Mon, Mar 01, 2010 at 07:10:30PM +0100, Jan Kiszka wrote: > >> This grand cleanup drops all reset and vmsave/load related >> synchronization points in favor of four(!) generic hooks: >> >> - cpu_synchronize_all_states in qemu_savevm_state_complete >> (initial sync from kernel before vmsave) >> - cpu_synchronize_all_post_init in qemu_loadvm_state >> (writeback after vmload) >> - cpu_synchronize_all_post_init in main after machine init >> - cpu_synchronize_all_post_reset in qemu_system_reset >> (writeback after system reset) >> >> These writeback points + the existing one of VCPU exec after >> cpu_synchronize_state map on three levels of writeback: >> >> - KVM_PUT_RUNTIME_STATE (during runtime, other VCPUs continue to run) >> - KVM_PUT_RESET_STATE (on synchronous system reset, all VCPUs stopped) >> - KVM_PUT_FULL_STATE (on init or vmload, all VCPUs stopped as well) >> >> This level is passed to the arch-specific VCPU state writing function >> that will decide which concrete substates need to be written. That way, >> no writer of load, save or reset functions that interact with in-kernel >> KVM states will ever have to worry about synchronization again. That >> also means that a lot of reasons for races, segfaults and deadlocks are >> eliminated. >> >> cpu_synchronize_state remains untouched, just as Anthony suggested. We >> continue to need it before reading or writing of VCPU states that are >> also tracked by in-kernel KVM subsystems. >> >> Consequently, this patch removes many cpu_synchronize_state calls that >> are now redundant, just like remaining explicit register syncs. >> >> Signed-off-by: Jan Kiszka >> > Jan, > > This patch breaks system reset of WinXP.32 install (more easily > reproducible without iothread enabled). > > What's the conclusion here? The patch is innocent of the regression? -- error compiling committee.c: too many arguments to function