From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gleb Natapov Subject: Re: [PATCH 2/5] Don't call svm_complete_interrupts for nested guests Date: Wed, 23 Sep 2009 11:28:20 +0300 Message-ID: <20090923082819.GV23157@redhat.com> References: <1253278832-31803-1-git-send-email-agraf@suse.de> <1253278832-31803-2-git-send-email-agraf@suse.de> <1253278832-31803-3-git-send-email-agraf@suse.de> <20090923012640.GC4654@8bytes.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Joerg Roedel , "kvm@vger.kernel.org" To: Alexander Graf Return-path: Received: from mx1.redhat.com ([209.132.183.28]:59204 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754581AbZIWI2W (ORCPT ); Wed, 23 Sep 2009 04:28:22 -0400 Content-Disposition: inline In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: On Wed, Sep 23, 2009 at 01:05:57AM -0700, Alexander Graf wrote: > > Am 22.09.2009 um 18:26 schrieb Joerg Roedel : > > >On Fri, Sep 18, 2009 at 03:00:29PM +0200, Alexander Graf wrote: > >>SVM has some cleanup code, that tries to reinject interrupts and > >>exceptions > >>when the guest didn't manage to deal with them yet. It basically > >>transfers > >>them to KVM internal state. > >> > >>Unfortunately, the internal state is reserved for the L1 guest > >>state, so we > >>shouldn't try to go through that logic when running a nested guest. > >> > >>When doing something the host KVM can handle, let's just > >>reinject the event > >>into the L2 guest, because we didn't touch its state anyways. > > > >I don't really understandt what problem this patch addresses. > >There are > >situations where we have events to reinject into the l2 guest > >directly. > >But the generic reinjection code works fine for it. > >The only problematic thing with it is that it implicitly relies on > >exit_int_info not to be changed in the exit cycle (which would be > >worth > >a comment). > > It simply tries to be too clever. Reevaluating exceptions won't work > for example. > Can you elaborate? What do you mean by "too clever" and why reevaluating exceptions won't work? -- Gleb.