From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: [PATCH] kvm: nVMX: check vmcs12 for valid activity state Date: Mon, 15 Apr 2013 14:54:12 +0200 Message-ID: <516BF874.7020608@siemens.com> References: <1366029996-3284-1-git-send-email-pbonzini@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: "linux-kernel@vger.kernel.org" , "gnatapov@redhat.com" , "kvm@vger.kernel.org" To: Paolo Bonzini Return-path: In-Reply-To: <1366029996-3284-1-git-send-email-pbonzini@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 2013-04-15 14:46, Paolo Bonzini wrote: > KVM does not use the activity state VMCS field, and does not support > it in nested VMX either (the corresponding bits in the misc VMX feature > MSR are zero). Fail entry if the activity state is set to anything but > "active". Ah, that indeed simplifies the issue. > > Signed-off-by: Paolo Bonzini > --- > arch/x86/kvm/vmx.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index c75c25d..589e79a 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -7223,6 +7223,11 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch) > return 1; > } > > + if (vmcs12->guest_activity_state != 0) { GUEST_ACTIVITY_ACTIVE, please. > + nested_vmx_failValid(vcpu, VMXERR_ENTRY_INVALID_CONTROL_FIELD); > + return 1; > + } > + > if ((vmcs12->cpu_based_vm_exec_control & CPU_BASED_USE_MSR_BITMAPS) && > !IS_ALIGNED(vmcs12->msr_bitmap, PAGE_SIZE)) { > /*TODO: Also verify bits beyond physical address width are 0*/ > That means we also do not need to read and write the corresponding VMCS field on L1/L2 transitions - avoids any risk of setting it to an unsupported value. So I would fold it into this change. Jan -- Siemens AG, Corporate Technology, CT RTC ITP SDP-DE Corporate Competence Center Embedded Linux