From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Tosatti Subject: KVM: x86: do not retain disabled or invalid pvclock address Date: Thu, 23 Aug 2012 08:16:54 -0300 Message-ID: <20120823111654.GA18057@amt.cnet> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm To: Avi Kivity Return-path: Received: from mx1.redhat.com ([209.132.183.28]:21625 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752534Ab2HWMC1 (ORCPT ); Thu, 23 Aug 2012 08:02:27 -0400 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q7NC2PgI029786 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Thu, 23 Aug 2012 08:02:25 -0400 Content-Disposition: inline Sender: kvm-owner@vger.kernel.org List-ID: In case an invalid or disabled gpa is written to the SYSTEM_TIME MSR, do not retain its value. This is not documented behaviour, nor should be supported. Also clear it on system reset. Not doing so can hide bugs. Signed-off-by: Marcelo Tosatti diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index e00050c..ed4bfb7 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1528,6 +1528,7 @@ static int kvm_pv_enable_async_pf(struct kvm_vcpu *vcpu, u64 data) static void kvmclock_reset(struct kvm_vcpu *vcpu) { + vcpu->arch.time = 0; if (vcpu->arch.time_page) { kvm_release_page_dirty(vcpu->arch.time_page); vcpu->arch.time_page = NULL; @@ -1632,8 +1633,10 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data) kvm_make_request(KVM_REQ_CLOCK_UPDATE, vcpu); /* we verify if the enable bit is set... */ - if (!(data & 1)) + if (!(data & 1)) { + vcpu->arch.time = 0; break; + } /* ...but clean it before doing the actual write */ vcpu->arch.time_offset = data & ~(PAGE_MASK | 1); @@ -1641,8 +1644,10 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, u32 msr, u64 data) vcpu->arch.time_page = gfn_to_page(vcpu->kvm, data >> PAGE_SHIFT); - if (is_error_page(vcpu->arch.time_page)) + if (is_error_page(vcpu->arch.time_page)) { vcpu->arch.time_page = NULL; + vcpu->arch.time = 0; + } break; }