From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 4/5] Userspace changes for KVM HPET (v6) Date: Sun, 14 Jun 2009 12:00:18 +0300 Message-ID: <4A34BC22.1040907@redhat.com> References: <1244771206-19872-1-git-send-email-eak@us.ibm.com> <1244771206-19872-4-git-send-email-eak@us.ibm.com> <4A34BAED.1030302@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org To: Beth Kon Return-path: Received: from mx2.redhat.com ([66.187.237.31]:53966 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750770AbZFNJAU (ORCPT ); Sun, 14 Jun 2009 05:00:20 -0400 In-Reply-To: <4A34BAED.1030302@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: Avi Kivity wrote: > Beth Kon wrote: >> The big change here is handling of enabling/disabling of hpet legacy >> mode. When hpet enters >> legacy mode, the spec says that the pit stops generating interrupts. >> In practice, we want to stop the pit periodic timer from running >> because it is wasteful in a virtual environment. >> We also have to worry about the hpet leaving legacy mode (which, at >> least in linux, happens >> only during a shutdown or crash). At this point, according to the >> hpet spec, PIT interrupts >> need to be reenabled. For us, it means the PIT timer needs to be >> restarted. >> This patch handles this situation better than the previous version by >> coming closer to just disabling PIT interrupts. It allows the PIT >> state to change if the OS modifies it, >> even while PIT is disabled, but does not allow a pit timer to start. >> Then if HPET >> legacy mode is disabled, whatever the PIT state is at that point, the >> PIT timer is restarted accordingly. >> >> > > Given that this depends on the ABI-breaking patch 5, I've dropped it too. > Actually, I got nervous about applying a partial patchset (which is likely to be untested), so I dropped everything else. I pushed the three patches to an 'hpet' branch of qemu-kvm.git, so you don't have to redo the rebasing I did. -- error compiling committee.c: too many arguments to function