From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joerg Roedel Subject: Re: [PATCH 7/8] KVM: x86: Allow marking an exception as reinjected Date: Fri, 23 Apr 2010 16:27:03 +0200 Message-ID: <20100423142702.GH31537@amd.com> References: <1271932394-13968-1-git-send-email-joerg.roedel@amd.com> <1271932394-13968-8-git-send-email-joerg.roedel@amd.com> <46B1F208-76A4-4C2F-9AE7-789264AB2D4B@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Cc: Avi Kivity , Marcelo Tosatti , kvm@vger.kernel.org, linux-kernel@vger.kernel.org To: Alexander Graf Return-path: Received: from va3ehsobe005.messaging.microsoft.com ([216.32.180.15]:24771 "EHLO VA3EHSOBE006.bigfish.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751862Ab0DWO1Q (ORCPT ); Fri, 23 Apr 2010 10:27:16 -0400 Content-Disposition: inline In-Reply-To: <46B1F208-76A4-4C2F-9AE7-789264AB2D4B@suse.de> Sender: kvm-owner@vger.kernel.org List-ID: On Fri, Apr 23, 2010 at 03:57:32PM +0200, Alexander Graf wrote: > > On 22.04.2010, at 12:33, Joerg Roedel wrote: > > > This patch adds logic to kvm/x86 which allows to mark an > > injected exception as reinjected. This allows to remove an > > ugly hack from svm_complete_interrupts that prevented > > exceptions from being reinjected at all in the nested case. > > The hack was necessary because an reinjected exception into > > the nested guest could cause a nested vmexit emulation. But > > reinjected exceptions must not intercept. The downside of > > the hack is that a exception that in injected could get > > lost. > > This patch fixes the problem and puts the code for it into > > generic x86 files because. Nested-VMX will likely have the > > same problem and could reuse the code. > > So we always handle the reinjection from KVM code? Shouldn't the l1 > hypervisor do this? No. We only have the problem if we need to handle a nested intercept on the host level instead of reinjecting it. So the nested hypervisor couldn't be involved in the reinjection. Joerg