Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752533AbaFONOG (ORCPT ); Sun, 15 Jun 2014 09:14:06 -0400 Received: from mailgw12.technion.ac.il ([132.68.225.12]:37326 "EHLO mailgw12.technion.ac.il" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752171AbaFONNP (ORCPT ); Sun, 15 Jun 2014 09:13:15 -0400 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AgECAPuanVOERCABjGdsb2JhbABariIBAQaZJAGBABYPAQEBJzyEBAEFJ1IQUVcZG4gnyViFJheFY4kTBxaELQSKOacl X-IPAS-Result: AgECAPuanVOERCABjGdsb2JhbABariIBAQaZJAGBABYPAQEBJzyEBAEFJ1IQUVcZG4gnyViFJheFY4kTBxaELQSKOacl X-IronPort-AV: E=Sophos;i="5.01,481,1400014800"; d="scan'208";a="111524004" From: Nadav Amit To: pbonzini@redhat.com Cc: gleb@kernel.org, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Nadav Amit Subject: [PATCH 4/6] KVM: x86: emulation of dword cmov on long-mode should clear [63:32] Date: Sun, 15 Jun 2014 16:13:00 +0300 Message-Id: <1402837982-24959-5-git-send-email-namit@cs.technion.ac.il> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1402837982-24959-1-git-send-email-namit@cs.technion.ac.il> References: <1402837982-24959-1-git-send-email-namit@cs.technion.ac.il> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Even if the condition of cmov is not satisfied, bits[63:32] should be cleared. This is clearly stated in Intel's CMOVcc documentation. The solution is to reassign the destination onto itself if the condition is unsatisfied. For that matter the original destination value needs to be read. Signed-off-by: Nadav Amit --- arch/x86/kvm/emulate.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 0183350..b354531 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -3905,7 +3905,7 @@ static const struct opcode twobyte_table[256] = { N, N, N, N, N, N, N, N, N, N, /* 0x40 - 0x4F */ - X16(D(DstReg | SrcMem | ModRM | Mov)), + X16(D(DstReg | SrcMem | ModRM)), /* 0x50 - 0x5F */ N, N, N, N, N, N, N, N, N, N, N, N, N, N, N, N, /* 0x60 - 0x6F */ @@ -4799,8 +4799,10 @@ twobyte_insn: ops->get_dr(ctxt, ctxt->modrm_reg, &ctxt->dst.val); break; case 0x40 ... 0x4f: /* cmov */ - ctxt->dst.val = ctxt->dst.orig_val = ctxt->src.val; - if (!test_cc(ctxt->b, ctxt->eflags)) + if (test_cc(ctxt->b, ctxt->eflags)) + ctxt->dst.val = ctxt->src.val; + else if (ctxt->mode != X86EMUL_MODE_PROT64 || + ctxt->op_bytes != 4) ctxt->dst.type = OP_NONE; /* no writeback */ break; case 0x80 ... 0x8f: /* jnz rel, etc*/ -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/