From patchwork Wed Dec 14 11:20:59 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Cooper X-Patchwork-Id: 9474061 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id BD94A60823 for ; Wed, 14 Dec 2016 11:22:30 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B57542871D for ; Wed, 14 Dec 2016 11:22:30 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A9D2F28720; Wed, 14 Dec 2016 11:22:30 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 9301D2871D for ; Wed, 14 Dec 2016 11:22:29 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1cH7cP-00014k-6Y; Wed, 14 Dec 2016 11:21:05 +0000 Received: from mail6.bemta3.messagelabs.com ([195.245.230.39]) by lists.xenproject.org with esmtp (Exim 4.84_2) (envelope-from ) id 1cH7cN-00014d-DL for xen-devel@lists.xen.org; Wed, 14 Dec 2016 11:21:03 +0000 Received: from [85.158.137.68] by server-5.bemta-3.messagelabs.com id 8F/6D-08140-E1B21585; Wed, 14 Dec 2016 11:21:02 +0000 X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFvrOLMWRWlGSWpSXmKPExsXitHSDva6cdmC Ewdf5AhZLPi5mcWD0OLr7N1MAYxRrZl5SfkUCa8ben5vYC25LVRy8s5uxgXG2cBcjJ4eEgL/E 6ed7mUFsNgF9id0vPjGB2CIC6hKnOy6ydjFycDAL+EkceuALEhYWsJV4u/EFG4jNIqAq8ffyJ bBWXgEPidNv1rBDjJSTOH/8J1hcSEBN4lr/JXaIGkGJkzOfsIDYzAISEgdfvGCewMg9C0lqFp LUAkamVYzqxalFZalFusZ6SUWZ6RkluYmZObqGBsZ6uanFxYnpqTmJScV6yfm5mxiBgcAABDs Ym784HWKU5GBSEuXluhoQIcSXlJ9SmZFYnBFfVJqTWnyIUYaDQ0mC97pmYISQYFFqempFWmYO MCRh0hIcPEoivLtA0rzFBYm5xZnpEKlTjLoc054tfsokxJKXn5cqJc77GqRIAKQoozQPbgQsP i4xykoJ8zICHSXEU5BalJtZgir/ilGcg1FJmJdbC2gKT2ZeCdymV0BHMAEdIbrEH+SIkkSElF QDo1ru5rrYb59LT0+b/PlQ+q33wVf6XOd17lD+sptti6n2B6ayD4b/JmSy3FRkvm0a5q/Ib5o g1vvq2aJf+208Ju3NE5kTEvxm06897IxOzSL/dzwUfP69oHLHqqe8F5+xxK9esWiTmTTv/heH vxwVDLTvOh93w6vg3YR3r48un/Zq7gGhiMnTrEKVWIozEg21mIuKEwES+dWligIAAA== X-Env-Sender: prvs=149b94f30=Andrew.Cooper3@citrix.com X-Msg-Ref: server-6.tower-31.messagelabs.com!1481714460!49711572!1 X-Originating-IP: [66.165.176.63] X-SpamReason: No, hits=0.0 required=7.0 tests=sa_preprocessor: VHJ1c3RlZCBJUDogNjYuMTY1LjE3Ni42MyA9PiAzMDYwNDg=\n, received_headers: No Received headers X-StarScan-Received: X-StarScan-Version: 9.1.1; banners=-,-,- X-VirusChecked: Checked Received: (qmail 33341 invoked from network); 14 Dec 2016 11:21:02 -0000 Received: from smtp02.citrix.com (HELO SMTP02.CITRIX.COM) (66.165.176.63) by server-6.tower-31.messagelabs.com with RC4-SHA encrypted SMTP; 14 Dec 2016 11:21:02 -0000 X-IronPort-AV: E=Sophos;i="5.33,346,1477958400"; d="scan'208";a="403545270" From: Andrew Cooper To: Xen-devel Date: Wed, 14 Dec 2016 11:20:59 +0000 Message-ID: <1481714459-6593-1-git-send-email-andrew.cooper3@citrix.com> X-Mailer: git-send-email 2.1.4 MIME-Version: 1.0 Cc: Andrew Cooper , Jan Beulich Subject: [Xen-devel] [PATCH] x86/emul: Simplfy L{ES,DS,SS,FS,GS} handling X-BeenThere: xen-devel@lists.xen.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xen.org Sender: "Xen-devel" X-Virus-Scanned: ClamAV using ClamSMTP %ss, %fs and %gs can be calculated by directly masking the opcode. %es and %ds cant, but the calculation isn't hard. Use seg rather than dst.val for storing the calculated segment, which is appropriately typed. The mode_64() check can be repositioned and simplified to drop the ext check. Replace opencoding of X86EMUL_OKAY. Finally, introduce assertions each time we calculate a user segment to load (rather than using constants) which don't have other validity checks. This includes the POP %sreg case. Signed-off-by: Andrew Cooper --- CC: Jan Beulich --- xen/arch/x86/x86_emulate/x86_emulate.c | 40 +++++++++++++++------------------- 1 file changed, 18 insertions(+), 22 deletions(-) diff --git a/xen/arch/x86/x86_emulate/x86_emulate.c b/xen/arch/x86/x86_emulate/x86_emulate.c index 1b5becf..2fb99e9 100644 --- a/xen/arch/x86/x86_emulate/x86_emulate.c +++ b/xen/arch/x86/x86_emulate/x86_emulate.c @@ -2765,6 +2765,7 @@ x86_emulate( if ( mode_64bit() && (op_bytes == 4) ) op_bytes = 8; seg = (b >> 3) & 7; + ASSERT(is_x86_user_segment(seg)); if ( (rc = read_ulong(x86_seg_ss, sp_post_inc(op_bytes), &dst.val, op_bytes, ctxt, ops)) != X86EMUL_OKAY || (rc = load_seg(seg, dst.val, 0, NULL, ctxt, ops)) != X86EMUL_OKAY ) @@ -3393,25 +3394,32 @@ x86_emulate( _regs.eip = dst.val; break; - case 0xc4: /* les */ { + case 0xc4: /* les */ + case 0xc5: /* lds */ + { unsigned long sel; - dst.val = x86_seg_es; - les: /* dst.val identifies the segment */ - generate_exception_if(mode_64bit() && !ext, EXC_UD); + + generate_exception_if(mode_64bit(), EXC_UD); + seg = (b & 1) * 3; /* es = 0, ds = 3 */ + goto les; + + case X86EMUL_OPC(0x0f, 0xb2): /* lss */ + case X86EMUL_OPC(0x0f, 0xb4): /* lfs */ + case X86EMUL_OPC(0x0f, 0xb5): /* lgs */ + seg = b & 7; + + les: generate_exception_if(src.type != OP_MEM, EXC_UD); if ( (rc = read_ulong(src.mem.seg, src.mem.off + src.bytes, - &sel, 2, ctxt, ops)) != 0 ) + &sel, 2, ctxt, ops)) != X86EMUL_OKAY ) goto done; - if ( (rc = load_seg(dst.val, sel, 0, NULL, ctxt, ops)) != 0 ) + ASSERT(is_x86_user_segment(seg)); + if ( (rc = load_seg(seg, sel, 0, NULL, ctxt, ops)) != X86EMUL_OKAY ) goto done; dst.val = src.val; break; } - case 0xc5: /* lds */ - dst.val = x86_seg_ds; - goto les; - case 0xc8: /* enter imm16,imm8 */ { uint8_t depth = imm2 & 31; int i; @@ -5228,22 +5236,10 @@ x86_emulate( } break; - case X86EMUL_OPC(0x0f, 0xb2): /* lss */ - dst.val = x86_seg_ss; - goto les; - case X86EMUL_OPC(0x0f, 0xb3): btr: /* btr */ emulate_2op_SrcV_nobyte("btr", src, dst, _regs.eflags); break; - case X86EMUL_OPC(0x0f, 0xb4): /* lfs */ - dst.val = x86_seg_fs; - goto les; - - case X86EMUL_OPC(0x0f, 0xb5): /* lgs */ - dst.val = x86_seg_gs; - goto les; - case X86EMUL_OPC(0x0f, 0xb6): /* movzx rm8,r{16,32,64} */ /* Recompute DstReg as we may have decoded AH/BH/CH/DH. */ dst.reg = decode_register(modrm_reg, &_regs, 0);