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From: Borislav Petkov <bp@alien8.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Borislav Petkov <bp@suse.de>, "H. Peter Anvin" <hpa@zytor.com>,
	Gleb Natapov <gleb@redhat.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Andre Przywara <andre@andrep.de>, Joerg Roedel <joro@8bytes.org>,
	X86 ML <x86@kernel.org>, KVM <kvm@vger.kernel.org>
Subject: [PATCH 2/6] kvm, emulator: Use opcode length
Date: Sun, 22 Sep 2013 16:44:51 +0200	[thread overview]
Message-ID: <1379861095-628-3-git-send-email-bp@alien8.de> (raw)
In-Reply-To: <1379861095-628-1-git-send-email-bp@alien8.de>

From: Borislav Petkov <bp@suse.de>

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 <bp@suse.de>
---
 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

  parent reply	other threads:[~2013-09-22 14:44 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-09-22 14:44 [PATCH 0/6] kvm: Emulate MOVBE, v3 Borislav Petkov
2013-09-22 14:44 ` [PATCH 1/6] kvm: Add KVM_GET_EMULATED_CPUID Borislav Petkov
2013-09-23 16:28   ` Eduardo Habkost
2013-09-24  9:57     ` Borislav Petkov
2013-09-24 10:04       ` Gleb Natapov
2013-09-26 14:19         ` Eduardo Habkost
2013-09-26 18:55           ` Borislav Petkov
2013-09-26 19:20             ` Eduardo Habkost
2013-09-26 20:32               ` Borislav Petkov
2013-09-27 14:21                 ` Eduardo Habkost
2013-09-28 10:49                   ` Borislav Petkov
2013-09-30 16:13                     ` Eduardo Habkost
2013-09-30 16:18                       ` Borislav Petkov
2013-09-22 14:44 ` Borislav Petkov [this message]
2013-09-22 14:44 ` [PATCH 3/6] kvm, emulator: Rename VendorSpecific flag Borislav Petkov
2013-09-22 14:44 ` [PATCH 4/6] kvm, emulator: Add initial three-byte insns support Borislav Petkov
2013-10-29  9:50   ` Gleb Natapov
2013-10-29 10:04     ` Borislav Petkov
2013-10-29 10:11       ` Gleb Natapov
2013-09-22 14:44 ` [PATCH 5/6] kvm: Emulate MOVBE Borislav Petkov
2013-09-22 14:44 ` [PATCH 6/6] qemu: Add support for emulated CPU features Borislav Petkov
2013-09-23 17:06   ` Eduardo Habkost
2013-10-29  9:53 ` [PATCH 0/6] kvm: Emulate MOVBE, v3 Gleb Natapov
2013-10-29 10:30   ` Borislav Petkov
2013-10-29 10:35     ` Gleb Natapov
2013-10-29 11:28       ` Borislav Petkov
2013-10-29 11:36         ` Gleb Natapov
2013-10-29 11:53           ` Borislav Petkov
2013-10-29 11:54             ` [PATCH 4/5 -v3.1] kvm, emulator: Add initial three-byte insns support Borislav Petkov
2013-10-29 11:54             ` [PATCH 5/5 -v3.1] kvm: Emulate MOVBE Borislav Petkov
2013-10-30 17:56               ` Paolo Bonzini
2013-10-30 18:03                 ` Borislav Petkov
2013-10-30 18:10 ` [PATCH 0/6] kvm: Emulate MOVBE, v3 Paolo Bonzini
2013-10-30 18:44   ` Borislav Petkov

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