From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Raj, Ashok" Subject: Re: [Qemu-devel] [Patch V2 1/2] x86, mce: Basic support to add LMCE support to QEMU Date: Mon, 14 Dec 2015 19:17:27 -0500 Message-ID: <20151215001726.GA22215@otc-brkl-03.jf.intel.com> References: <1449776482-26070-1-git-send-email-ashok.raj@intel.com> <20151214162356.GA5314@thinpad.lan.raisama.net> <20151214163738.GJ11630@pd.tnic> <20151214191145.GB18012@otc-brkl-03.jf.intel.com> <20151214223716.GK11630@pd.tnic> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Eduardo Habkost , kvm@vger.kernel.org, Tony Luck , Gong Chen , Gleb Natapov , linux-kernel@vger.kernel.org, qemu-devel@nongnu.org, Andi Kleen , Paolo Bonzini , Ashok Raj To: Borislav Petkov Return-path: Content-Disposition: inline In-Reply-To: <20151214223716.GK11630@pd.tnic> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On Mon, Dec 14, 2015 at 11:37:16PM +0100, Borislav Petkov wrote: > On Mon, Dec 14, 2015 at 02:11:46PM -0500, Raj, Ashok wrote: > > This is mostly harmless.. since the MCG_CAP space is shared and has no > > conflict between vendors. Also just the CAP being set has no effect. > > Of course it does - we check SER_P in machine_check_poll() and when > I emulate an AMD guest and inject errors into it, error handling is > obviously wrong, see: > > https://lkml.kernel.org/r/20151123150355.GE5134@pd.tnic > I can see how this hurts.. since the poller isn't doing cpu model specific stuff..? in the LMCE case, even if you advertise MCG_LMCE_P in MCG_CAP, the guest kernel wont call intel_init_lmce() only from mce_intel.c.. so the same problem won't happen. but the issue Eduardo mentioned seems like the following. New QEMU_LMCE + New KVM_LMCE + New_GUEST_LMCE - No problem but if you were to migrage the Guest_LMCE to a non-LMCE supported KVM host we could run into an issue.. is this the compatibility issue that you were looking to fix Eduardo? Cheers, Ashok