From patchwork Wed Dec 11 09:28:19 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Beulich X-Patchwork-Id: 11284559 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9F8F36C1 for ; Wed, 11 Dec 2019 09:29:10 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 865442054F for ; Wed, 11 Dec 2019 09:29:10 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 865442054F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1ieyHp-0005XT-Ja; Wed, 11 Dec 2019 09:28:01 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1ieyHo-0005XJ-5B for xen-devel@lists.xenproject.org; Wed, 11 Dec 2019 09:28:00 +0000 X-Inumbo-ID: 842080ef-1bf8-11ea-8ade-12813bfff9fa Received: from mx1.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 842080ef-1bf8-11ea-8ade-12813bfff9fa; Wed, 11 Dec 2019 09:27:59 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 70660AD10; Wed, 11 Dec 2019 09:27:58 +0000 (UTC) To: "xen-devel@lists.xenproject.org" From: Jan Beulich Message-ID: Date: Wed, 11 Dec 2019 10:28:19 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.9.1 MIME-Version: 1.0 Content-Language: en-US Subject: [Xen-devel] [PATCH] x86emul: correct LFS et al handling for 64-bit mode X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Andrew Cooper , Wei Liu , =?utf-8?q?Roger_Pau_Monn=C3=A9?= Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" AMD and friends explicitly specify that 64-bit operands aren't possible for these insns. Nevertheless REX.W isn't fully ignored: It still cancels a possible operand size override (0x66). Intel otoh explicitly provides for 64-bit operands on the respective insn page of the SDM. Signed-off-by: Jan Beulich --- a/xen/arch/x86/x86_emulate/x86_emulate.c +++ b/xen/arch/x86/x86_emulate/x86_emulate.c @@ -2640,6 +2640,15 @@ x86_decode_twobyte( } break; + case 0xb2: /* lss */ + case 0xb4: /* lfs */ + case 0xb5: /* lgs */ + /* REX.W ignored on a vendor-dependent basis. */ + if ( op_bytes == 8 && + (ctxt->cpuid->x86_vendor & (X86_VENDOR_AMD | X86_VENDOR_HYGON)) ) + op_bytes = 4; + break; + case 0xb8: /* jmpe / popcnt */ if ( rep_prefix() ) ctxt->opcode |= MASK_INSR(vex.pfx, X86EMUL_OPC_PFX_MASK);