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authorBorislav Petkov <bp@suse.de>2013-09-22 16:44:51 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2013-10-30 18:54:39 +0100
commit1ce19dc16ce9136cccb6087e4a383ec9321980d9 (patch)
treee93153a04096bf907dee183cc4b2260c5752991f /arch/x86
parent9c15bb1d0a8411f9bb3395d21d5309bde7da0c1c (diff)
kvm, emulator: Use opcode length
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> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/include/asm/kvm_emulate.h8
-rw-r--r--arch/x86/kvm/emulate.c5
-rw-r--r--arch/x86/kvm/x86.c4
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 ddc3f3d2afdb..d554d96afbca 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -4126,6 +4126,7 @@ 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);
@@ -4208,7 +4209,7 @@ 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];
}
@@ -4540,7 +4541,7 @@ 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 3d1e3ee8b39e..d00d88455fef 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4789,8 +4789,8 @@ 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;

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