From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752447Ab3IVOpJ (ORCPT ); Sun, 22 Sep 2013 10:45:09 -0400 Received: from mail.skyhub.de ([78.46.96.112]:53474 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752338Ab3IVOpG (ORCPT ); Sun, 22 Sep 2013 10:45:06 -0400 From: Borislav Petkov To: LKML Cc: Borislav Petkov , "H. Peter Anvin" , Gleb Natapov , Paolo Bonzini , Andre Przywara , Joerg Roedel , X86 ML , KVM Subject: [PATCH 2/6] kvm, emulator: Use opcode length Date: Sun, 22 Sep 2013 16:44:51 +0200 Message-Id: <1379861095-628-3-git-send-email-bp@alien8.de> X-Mailer: git-send-email 1.8.4 In-Reply-To: <1379861095-628-1-git-send-email-bp@alien8.de> References: <1379861095-628-1-git-send-email-bp@alien8.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Borislav Petkov Add a field to the current emulation context which contains the instruction opcode length. This will streamline handling of opcodes of different length. Signed-off-by: Borislav Petkov --- arch/x86/include/asm/kvm_emulate.h | 8 ++++++-- arch/x86/kvm/emulate.c | 5 +++-- arch/x86/kvm/x86.c | 4 ++-- 3 files changed, 11 insertions(+), 6 deletions(-) diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h index 15f960c06ff7..92a176ad456c 100644 --- a/arch/x86/include/asm/kvm_emulate.h +++ b/arch/x86/include/asm/kvm_emulate.h @@ -279,8 +279,12 @@ struct x86_emulate_ctxt { bool have_exception; struct x86_exception exception; - /* decode cache */ - u8 twobyte; + /* + * decode cache + */ + + /* current opcode length in bytes */ + u8 opcode_len; u8 b; u8 intercept; u8 lock_prefix; diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 2bc1e81045b0..bfae4a433091 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -4114,6 +4114,7 @@ int x86_decode_insn(struct x86_emulate_ctxt *ctxt, void *insn, int insn_len) ctxt->_eip = ctxt->eip; ctxt->fetch.start = ctxt->_eip; ctxt->fetch.end = ctxt->fetch.start + insn_len; + ctxt->opcode_len = 1; if (insn_len > 0) memcpy(ctxt->fetch.data, insn, insn_len); @@ -4196,7 +4197,7 @@ done_prefixes: opcode = opcode_table[ctxt->b]; /* Two-byte opcode? */ if (ctxt->b == 0x0f) { - ctxt->twobyte = 1; + ctxt->opcode_len = 2; ctxt->b = insn_fetch(u8, ctxt); opcode = twobyte_table[ctxt->b]; } @@ -4528,7 +4529,7 @@ special_insn: goto writeback; } - if (ctxt->twobyte) + if (ctxt->opcode_len == 2) goto twobyte_insn; switch (ctxt->b) { diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 8dfde7a52dab..6f2ea40b80cf 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4778,8 +4778,8 @@ static void inject_emulated_exception(struct kvm_vcpu *vcpu) static void init_decode_cache(struct x86_emulate_ctxt *ctxt) { - memset(&ctxt->twobyte, 0, - (void *)&ctxt->_regs - (void *)&ctxt->twobyte); + memset(&ctxt->opcode_len, 0, + (void *)&ctxt->_regs - (void *)&ctxt->opcode_len); ctxt->fetch.start = 0; ctxt->fetch.end = 0; -- 1.8.4