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kvm, emulator: Use opcode length

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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>
This commit is contained in:
Borislav Petkov 2013-09-22 16:44:51 +02:00 committed by Paolo Bonzini
parent 9c15bb1d0a
commit 1ce19dc16c
3 changed files with 11 additions and 6 deletions
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8
arch/x86/include/asm/kvm_emulate.h
View File

@ -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;

5
arch/x86/kvm/emulate.c
View File

@ -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) {

4
arch/x86/kvm/x86.c
View File

@ -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;