From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: [PATCH] Xen 4.4-rc3 regression with PVH compared to Xen 4.4-rc2. Date: Mon, 3 Feb 2014 12:03:20 -0500 Message-ID: <1391447001-19100-1-git-send-email-konrad.wilk@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta3.messagelabs.com ([195.245.230.39]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1WAMzY-0003PW-Bf for xen-devel@lists.xenproject.org; Mon, 03 Feb 2014 17:07:28 +0000 Received: by mail-qa0-f49.google.com with SMTP id w8so10292271qac.22 for ; Mon, 03 Feb 2014 09:07:25 -0800 (PST) List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: jbeulich@suse.com, george.dunlap@eu.citrix.com, xen-devel@lists.xenproject.org, jun.nakajima@intel.com, mukesh.rathor@oracle.com, yang.z.zhang@Intel.com List-Id: xen-devel@lists.xenproject.org I am hereby requesting an Xen 4.4 exemption for this bug-fix. The PVH feature is considered experimental, but it would be good to have it working out of the box without crashing the hypervisor. Sadly that is not the case as 09bb434748af9bfe3f7fca4b6eef721a7d5042a4 "Nested VMX: prohibit virtual vmentry/vmexit during IO emulation" casues an NULL pointer dereference when starting a guest with 'pvh=1' in the guest config. There are two ways of fixing this: a). Add an '!xen_pvh_domain()' or '!xen_pvh_vcpu(current)' in the path, or b). Check for ioreq() being NULL. This is actually done in other places in the hypervisor - so I choose to piggyback on that. Thank you! xen/arch/x86/hvm/vmx/vvmx.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) Konrad Rzeszutek Wilk (1): pvh: Fix regression caused by assumption that HVM paths MUST use io-backend device.