[RFC PATCH 3/5] KVM: x86: move around some checks

From: Paolo Bonzini
Date: Thu Mar 27 2014 - 07:31:15 EST


The only purpose of this patch is to make the next patch simpler
to review. No semantic change.

Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
arch/x86/kvm/emulate.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index c9f8f61df46c..9e40fbf94dcd 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -4347,12 +4347,15 @@ done_prefixes:
ctxt->d |= opcode.flags;
}

+ /* Unrecognised? */
+ if (ctxt->d == 0)
+ return EMULATION_FAILED;
+
ctxt->execute = opcode.u.execute;
ctxt->check_perm = opcode.check_perm;
ctxt->intercept = opcode.intercept;

- /* Unrecognised? */
- if (ctxt->d == 0 || (ctxt->d & NotImpl))
+ if (ctxt->d & NotImpl)
return EMULATION_FAILED;

if (!(ctxt->d & EmulateOnUD) && ctxt->ud)
@@ -4494,19 +4497,19 @@ int x86_emulate_insn(struct x86_emulate_ctxt *ctxt)

ctxt->mem_read.pos = 0;

- if ((ctxt->mode == X86EMUL_MODE_PROT64 && (ctxt->d & No64)) ||
- (ctxt->d & Undefined)) {
+ /* LOCK prefix is allowed only with some instructions */
+ if (ctxt->lock_prefix && (!(ctxt->d & Lock) || ctxt->dst.type != OP_MEM)) {
rc = emulate_ud(ctxt);
goto done;
}

- /* LOCK prefix is allowed only with some instructions */
- if (ctxt->lock_prefix && (!(ctxt->d & Lock) || ctxt->dst.type != OP_MEM)) {
+ if ((ctxt->d & SrcMask) == SrcMemFAddr && ctxt->src.type != OP_MEM) {
rc = emulate_ud(ctxt);
goto done;
}

- if ((ctxt->d & SrcMask) == SrcMemFAddr && ctxt->src.type != OP_MEM) {
+ if ((ctxt->mode == X86EMUL_MODE_PROT64 && (ctxt->d & No64)) ||
+ (ctxt->d & Undefined)) {
rc = emulate_ud(ctxt);
goto done;
}
--
1.8.3.1


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