From patchwork Fri May 30 12:42:44 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Graf X-Patchwork-Id: 354142 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 0E410140100 for ; Fri, 30 May 2014 22:44:17 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752069AbaE3MoP (ORCPT ); Fri, 30 May 2014 08:44:15 -0400 Received: from cantor2.suse.de ([195.135.220.15]:34293 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755511AbaE3MnF (ORCPT ); Fri, 30 May 2014 08:43:05 -0400 Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 0473DAD59; Fri, 30 May 2014 12:42:58 +0000 (UTC) From: Alexander Graf To: kvm-ppc@vger.kernel.org Cc: kvm@vger.kernel.org, pbonzini@redhat.com, mtosatti@redhat.com Subject: [PULL 29/41] KVM: PPC: Graciously fail broken LE hypercalls Date: Fri, 30 May 2014 14:42:44 +0200 Message-Id: <1401453776-55285-30-git-send-email-agraf@suse.de> X-Mailer: git-send-email 1.8.1.4 In-Reply-To: <1401453776-55285-1-git-send-email-agraf@suse.de> References: <1401453776-55285-1-git-send-email-agraf@suse.de> Sender: kvm-ppc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm-ppc@vger.kernel.org There are LE Linux guests out there that don't handle hypercalls correctly. Instead of interpreting the instruction stream from device tree as big endian they assume it's a little endian instruction stream and fail. When we see an illegal instruction from such a byte reversed instruction stream, bail out graciously and just declare every hcall as error. Signed-off-by: Alexander Graf --- arch/powerpc/kvm/book3s_emulate.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/arch/powerpc/kvm/book3s_emulate.c b/arch/powerpc/kvm/book3s_emulate.c index c992447..3f29526 100644 --- a/arch/powerpc/kvm/book3s_emulate.c +++ b/arch/powerpc/kvm/book3s_emulate.c @@ -94,8 +94,25 @@ int kvmppc_core_emulate_op_pr(struct kvm_run *run, struct kvm_vcpu *vcpu, int rs = get_rs(inst); int ra = get_ra(inst); int rb = get_rb(inst); + u32 inst_sc = 0x44000002; switch (get_op(inst)) { + case 0: + emulated = EMULATE_FAIL; + if ((kvmppc_get_msr(vcpu) & MSR_LE) && + (inst == swab32(inst_sc))) { + /* + * This is the byte reversed syscall instruction of our + * hypercall handler. Early versions of LE Linux didn't + * swap the instructions correctly and ended up in + * illegal instructions. + * Just always fail hypercalls on these broken systems. + */ + kvmppc_set_gpr(vcpu, 3, EV_UNIMPLEMENTED); + kvmppc_set_pc(vcpu, kvmppc_get_pc(vcpu) + 4); + emulated = EMULATE_DONE; + } + break; case 19: switch (get_xop(inst)) { case OP_19_XOP_RFID: