From patchwork Mon Mar 30 13:03:24 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gleb Natapov X-Patchwork-Id: 15128 Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by demeter.kernel.org (8.14.2/8.14.2) with ESMTP id n2UD3SaD031027 for ; Mon, 30 Mar 2009 13:03:28 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752448AbZC3ND1 (ORCPT ); Mon, 30 Mar 2009 09:03:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752857AbZC3ND1 (ORCPT ); Mon, 30 Mar 2009 09:03:27 -0400 Received: from mx2.redhat.com ([66.187.237.31]:41526 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752233AbZC3ND0 (ORCPT ); Mon, 30 Mar 2009 09:03:26 -0400 Received: from int-mx2.corp.redhat.com (int-mx2.corp.redhat.com [172.16.27.26]) by mx2.redhat.com (8.13.8/8.13.8) with ESMTP id n2UD3PWH011620 for ; Mon, 30 Mar 2009 09:03:25 -0400 Received: from ns3.rdu.redhat.com (ns3.rdu.redhat.com [10.11.255.199]) by int-mx2.corp.redhat.com (8.13.1/8.13.1) with ESMTP id n2UD3PaP000572; Mon, 30 Mar 2009 09:03:25 -0400 Received: from dhcp-1-237.tlv.redhat.com (dhcp-1-237.tlv.redhat.com [10.35.1.237]) by ns3.rdu.redhat.com (8.13.8/8.13.8) with ESMTP id n2UD3Od1015778; Mon, 30 Mar 2009 09:03:24 -0400 Received: from trex.usersys.redhat.com (localhost [127.0.0.1]) by dhcp-1-237.tlv.redhat.com (Postfix) with ESMTP id 3503E18D395; Mon, 30 Mar 2009 16:03:24 +0300 (IDT) From: Gleb Natapov Subject: [PATCH v2 4/5] Fix task switch back link handling. To: avi@redhat.com Cc: kvm@vger.kernel.org Date: Mon, 30 Mar 2009 16:03:24 +0300 Message-ID: <20090330130324.31823.37736.stgit@trex.usersys.redhat.com> In-Reply-To: <20090330130308.31823.11156.stgit@trex.usersys.redhat.com> References: <20090330130308.31823.11156.stgit@trex.usersys.redhat.com> User-Agent: StGIT/0.14.2 MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.58 on 172.16.27.26 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Back link is written to a wrong TSS now. Signed-off-by: Gleb Natapov --- arch/x86/kvm/x86.c | 40 ++++++++++++++++++++++++++++++++-------- 1 files changed, 32 insertions(+), 8 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index ae4918c..f14c622 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3697,7 +3697,6 @@ static void save_state_to_tss32(struct kvm_vcpu *vcpu, tss->fs = get_segment_selector(vcpu, VCPU_SREG_FS); tss->gs = get_segment_selector(vcpu, VCPU_SREG_GS); tss->ldt_selector = get_segment_selector(vcpu, VCPU_SREG_LDTR); - tss->prev_task_link = get_segment_selector(vcpu, VCPU_SREG_TR); } static int load_state_from_tss32(struct kvm_vcpu *vcpu, @@ -3794,8 +3793,8 @@ static int load_state_from_tss16(struct kvm_vcpu *vcpu, } static int kvm_task_switch_16(struct kvm_vcpu *vcpu, u16 tss_selector, - u32 old_tss_base, - struct desc_struct *nseg_desc) + u16 old_tss_sel, u32 old_tss_base, + struct desc_struct *nseg_desc) { struct tss_segment_16 tss_segment_16; int ret = 0; @@ -3814,6 +3813,16 @@ static int kvm_task_switch_16(struct kvm_vcpu *vcpu, u16 tss_selector, &tss_segment_16, sizeof tss_segment_16)) goto out; + if (old_tss_sel != 0xffff) { + tss_segment_16.prev_task_link = old_tss_sel; + + if (kvm_write_guest(vcpu->kvm, + get_tss_base_addr(vcpu, nseg_desc), + &tss_segment_16.prev_task_link, + sizeof tss_segment_16.prev_task_link)) + goto out; + } + if (load_state_from_tss16(vcpu, &tss_segment_16)) goto out; @@ -3823,7 +3832,7 @@ out: } static int kvm_task_switch_32(struct kvm_vcpu *vcpu, u16 tss_selector, - u32 old_tss_base, + u16 old_tss_sel, u32 old_tss_base, struct desc_struct *nseg_desc) { struct tss_segment_32 tss_segment_32; @@ -3843,6 +3852,16 @@ static int kvm_task_switch_32(struct kvm_vcpu *vcpu, u16 tss_selector, &tss_segment_32, sizeof tss_segment_32)) goto out; + if (old_tss_sel != 0xffff) { + tss_segment_32.prev_task_link = old_tss_sel; + + if (kvm_write_guest(vcpu->kvm, + get_tss_base_addr(vcpu, nseg_desc), + &tss_segment_32.prev_task_link, + sizeof tss_segment_32.prev_task_link)) + goto out; + } + if (load_state_from_tss32(vcpu, &tss_segment_32)) goto out; @@ -3898,12 +3917,17 @@ int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int reason) kvm_x86_ops->skip_emulated_instruction(vcpu); + /* set back link to prev task only if NT bit is set in eflags + note that old_tss_sel is not used afetr this point */ + if (reason != TASK_SWITCH_CALL && reason != TASK_SWITCH_GATE) + old_tss_sel = 0xffff; + if (nseg_desc.type & 8) - ret = kvm_task_switch_32(vcpu, tss_selector, old_tss_base, - &nseg_desc); + ret = kvm_task_switch_32(vcpu, tss_selector, old_tss_sel, + old_tss_base, &nseg_desc); else - ret = kvm_task_switch_16(vcpu, tss_selector, old_tss_base, - &nseg_desc); + ret = kvm_task_switch_16(vcpu, tss_selector, old_tss_sel, + old_tss_base, &nseg_desc); if (reason == TASK_SWITCH_CALL || reason == TASK_SWITCH_GATE) { u32 eflags = kvm_x86_ops->get_rflags(vcpu);