From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755490Ab0BPKkP (ORCPT ); Tue, 16 Feb 2010 05:40:15 -0500 Received: from mx1.redhat.com ([209.132.183.28]:12086 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932476Ab0BPKfl (ORCPT ); Tue, 16 Feb 2010 05:35:41 -0500 From: Avi Kivity To: kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Subject: [PATCH 31/38] KVM: fix load_guest_segment_descriptor() to return X86EMUL_* Date: Tue, 16 Feb 2010 12:35:29 +0200 Message-Id: <1266316536-28936-32-git-send-email-avi@redhat.com> In-Reply-To: <1266316536-28936-1-git-send-email-avi@redhat.com> References: <1266316536-28936-1-git-send-email-avi@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Takuya Yoshikawa This patch fixes load_guest_segment_descriptor() to return X86EMUL_PROPAGATE_FAULT when it tries to access the descriptor table beyond the limit of it: suggested by Marcelo. I have checked current callers of this helper function, - kvm_load_segment_descriptor() - kvm_task_switch() and confirmed that this patch will change nothing in the upper layers if we do not change the handling of this return value from load_guest_segment_descriptor(). Next step: Although fixing the kvm_task_switch() to handle the propagated faults properly seems difficult, and maybe not worth it because TSS is not used commonly these days, we can fix kvm_load_segment_descriptor(). By doing so, the injected #GP becomes possible to be handled by the guest. The only problem for this is how to differentiate this fault from the page faults generated by kvm_read_guest_virt(). We may have to split this function to achive this goal. Signed-off-by: Takuya Yoshikawa Signed-off-by: Marcelo Tosatti --- arch/x86/kvm/x86.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 0bf3df5..01f0b03 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4663,7 +4663,7 @@ static int load_guest_segment_descriptor(struct kvm_vcpu *vcpu, u16 selector, if (dtable.limit < index * 8 + 7) { kvm_queue_exception_e(vcpu, GP_VECTOR, selector & 0xfffc); - return 1; + return X86EMUL_PROPAGATE_FAULT; } return kvm_read_guest_virt(dtable.base + index*8, seg_desc, sizeof(*seg_desc), vcpu); } -- 1.6.5.3