From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Mackerras Subject: [PATCH 7/8] KVM: PPC: Book3S HV: Allow DTL to be set to address 0, length 0 Date: Tue, 16 Oct 2012 14:06:30 +1100 Message-ID: <20121016030630.GH1218@drongo> References: <20121016030303.GA1218@drongo> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm@vger.kernel.org To: Alexander Graf Return-path: Received: from ozlabs.org ([203.10.76.45]:35990 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752756Ab2JPDH1 (ORCPT ); Mon, 15 Oct 2012 23:07:27 -0400 Content-Disposition: inline In-Reply-To: <20121016030303.GA1218@drongo> Sender: kvm-owner@vger.kernel.org List-ID: Commit 55b665b026 ("KVM: PPC: Book3S HV: Provide a way for userspace to get/set per-vCPU areas") includes a check on the length of the dispatch trace log (DTL) to make sure the buffer is at least one entry long. This is appropriate when registering a buffer, but the interface also allows for any existing buffer to be unregistered by specifying a zero address. In this case the length check is not appropriate. This makes the check conditional on the address being non-zero. Signed-off-by: Paul Mackerras --- arch/powerpc/kvm/book3s_hv.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c index 8b3c470..812764c 100644 --- a/arch/powerpc/kvm/book3s_hv.c +++ b/arch/powerpc/kvm/book3s_hv.c @@ -811,9 +811,8 @@ int kvmppc_set_one_reg(struct kvm_vcpu *vcpu, u64 id, union kvmppc_one_reg *val) addr = val->vpaval.addr; len = val->vpaval.length; r = -EINVAL; - if (len < sizeof(struct dtl_entry)) - break; - if (addr && !vcpu->arch.vpa.next_gpa) + if (addr && (len < sizeof(struct dtl_entry) || + !vcpu->arch.vpa.next_gpa)) break; len -= len % sizeof(struct dtl_entry); r = set_vpa(vcpu, &vcpu->arch.dtl, addr, len); -- 1.7.10.4