Commit 1ce19dc1 authored by Borislav Petkov's avatar Borislav Petkov Committed by Paolo Bonzini
Browse files

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: default avatarBorislav Petkov <bp@suse.de>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 9c15bb1d
......@@ -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;
......
......@@ -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) {
......
......@@ -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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