From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: [PATCH v2 01/26] KVM: VMX: Return correct CPL during transition to protected mode Date: Wed, 27 Jun 2012 18:18:59 +0300 Message-ID: <1340810369-25392-2-git-send-email-avi@redhat.com> References: <1340810369-25392-1-git-send-email-avi@redhat.com> Cc: kvm@vger.kernel.org To: Marcelo Tosatti Return-path: Received: from mx1.redhat.com ([209.132.183.28]:13641 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757633Ab2F0PTf (ORCPT ); Wed, 27 Jun 2012 11:19:35 -0400 Received: from int-mx12.intmail.prod.int.phx2.redhat.com (int-mx12.intmail.prod.int.phx2.redhat.com [10.5.11.25]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q5RFJZYW030595 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Wed, 27 Jun 2012 11:19:35 -0400 In-Reply-To: <1340810369-25392-1-git-send-email-avi@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: In protected mode, the CPL is defined as the lower two bits of CS, as set by the last far jump. But during the transition to protected mode, there is no last far jump, so we need to return zero (the inherited real mode CPL). Fix by reading CPL from the cache during the transition. This isn't 100% correct since we don't set the CPL cache on a far jump, but since protected mode transition will always jump to a segment with RPL=0, it will always work. Signed-off-by: Avi Kivity --- arch/x86/kvm/vmx.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index eeeb4a2..8f2ddd9 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -3175,11 +3175,22 @@ static int __vmx_get_cpl(struct kvm_vcpu *vcpu) static int vmx_get_cpl(struct kvm_vcpu *vcpu) { + struct vcpu_vmx *vmx = to_vmx(vcpu); + + /* + * If we enter real mode with cs.sel & 3 != 0, the normal CPL calculations + * fail; use the cache instead. + */ + if (unlikely(vmx->emulation_required && emulate_invalid_guest_state)) { + return vmx->cpl; + } + if (!test_bit(VCPU_EXREG_CPL, (ulong *)&vcpu->arch.regs_avail)) { __set_bit(VCPU_EXREG_CPL, (ulong *)&vcpu->arch.regs_avail); - to_vmx(vcpu)->cpl = __vmx_get_cpl(vcpu); + vmx->cpl = __vmx_get_cpl(vcpu); } - return to_vmx(vcpu)->cpl; + + return vmx->cpl; } -- 1.7.11