From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [PATCH] KVM: VMX: Preserve host CR4.MCE value while in guest mode. Date: Fri, 17 Apr 2015 12:10:39 +0200 Message-ID: <5530DC1F.5000106@redhat.com> References: <1429210685-19510-1-git-send-email-serebrin@google.com> <20150417085539.GA22515@kroah.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, stable@vger.kernel.org, luto@amacapital.net, jankiszka@siemens.com To: Greg KH , Ben Serebrin Return-path: In-Reply-To: <20150417085539.GA22515@kroah.com> Sender: stable-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 17/04/2015 10:55, Greg KH wrote: > On Thu, Apr 16, 2015 at 11:58:05AM -0700, Ben Serebrin wrote: >> > The host's decision to enable machine check exceptions should remain >> > in force during non-root mode. KVM was writing 0 to cr4 on VCPU reset >> > and passed a slightly-modified 0 to the vmcs.guest_cr4 value. >> > >> > Tested: Built. >> > On earlier version, tested by injecting machine check >> > while a guest is spinning. >> > >> > Before the change, if guest CR4.MCE==0, then the machine check is >> > escalated to Catastrophic Error (CATERR) and the machine dies. >> > If guest CR4.MCE==1, then the machine check causes VMEXIT and is >> > handled normally by host Linux. After the change, injecting a machine >> > check causes normal Linux machine check handling. >> > >> > Signed-off-by: Ben Serebrin >> > --- >> > arch/x86/kvm/vmx.c | 12 ++++++++++-- >> > 1 file changed, 10 insertions(+), 2 deletions(-) > > > This is not the correct way to submit patches for inclusion in the > stable kernel tree. Please read Documentation/stable_kernel_rules.txt > for how to do this properly. I'll fix it up when applying to the KVM tree. Paolo