Some instructions write back the source operand, not just the destination.
Add support for doing this via the decode flags.
Signed-off-by: Avi Kivity <avi.kivity@xxxxxxxxx>
---
arch/x86/kvm/emulate.c | 47 ++++++++++++++++++++++++++---------------------
1 file changed, 26 insertions(+), 21 deletions(-)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 2b11318..18c86b5 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -152,6 +152,7 @@
#define Avx ((u64)1 << 43) /* Advanced Vector Extensions */
#define Fastop ((u64)1 << 44) /* Use opcode::u.fastop */
#define NoWrite ((u64)1 << 45) /* No writeback */
+#define SrcWrite ((u64)1 << 46) /* Write back src operand */
#define X2(x...) x, x
#define X3(x...) X2(x), x
@@ -1708,45 +1709,42 @@ static void write_register_operand(struct operand *op)
}
}
-static int writeback(struct x86_emulate_ctxt *ctxt)
+static int writeback(struct x86_emulate_ctxt *ctxt, struct operand *op)
{
int rc;
- if (ctxt->d & NoWrite)
- return X86EMUL_CONTINUE;
-
- switch (ctxt->dst.type) {
+ switch (op->type) {
case OP_REG:
- write_register_operand(&ctxt->dst);
+ write_register_operand(op);
break;
case OP_MEM:
if (ctxt->lock_prefix)
rc = segmented_cmpxchg(ctxt,
- ctxt->dst.addr.mem,
- &ctxt->dst.orig_val,
- &ctxt->dst.val,
- ctxt->dst.bytes);
+ op->addr.mem,
+ &op->orig_val,
+ &op->val,
+ op->bytes);
else
rc = segmented_write(ctxt,
- ctxt->dst.addr.mem,
- &ctxt->dst.val,
- ctxt->dst.bytes);
+ op->addr.mem,
+ &op->val,
+ op->bytes);
if (rc != X86EMUL_CONTINUE)
return rc;
break;
case OP_MEM_STR:
rc = segmented_write(ctxt,
- ctxt->dst.addr.mem,
- ctxt->dst.data,
- ctxt->dst.bytes * ctxt->dst.count);
+ op->addr.mem,
+ op->data,
+ op->bytes * op->count);
if (rc != X86EMUL_CONTINUE)
return rc;
break;
case OP_XMM:
- write_sse_reg(ctxt, &ctxt->dst.vec_val, ctxt->dst.addr.xmm);
+ write_sse_reg(ctxt, &op->vec_val, op->addr.xmm);
break;
case OP_MM:
- write_mmx_reg(ctxt, &ctxt->dst.mm_val, ctxt->dst.addr.mm);
+ write_mmx_reg(ctxt, &op->mm_val, op->addr.mm);
break;
case OP_NONE:
/* no writeback */
@@ -4717,9 +4715,16 @@ special_insn:
goto done;
writeback:
- rc = writeback(ctxt);
- if (rc != X86EMUL_CONTINUE)
- goto done;
+ if (!(ctxt->d & NoWrite)) {
+ rc = writeback(ctxt, &ctxt->dst);
+ if (rc != X86EMUL_CONTINUE)
+ goto done;
+ }
+ if (ctxt->d & SrcWrite) {
+ rc = writeback(ctxt, &ctxt->src);
+ if (rc != X86EMUL_CONTINUE)
+ goto done;
+ }
/*
* restore dst type in case the decoding will be reused
--
1.8.1.2
--
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