On 08/17/2010 12:13 PM, Gleb Natapov wrote:
On Tue, Aug 17, 2010 at 11:26:43AM +0300, Avi Kivity wrote:
EFLAGS.ZF needs to be checked after each iteration, not before.
Signed-off-by: Avi Kivity<[email protected]>
---
arch/x86/kvm/emulate.c | 42 +++++++++++++++++++++++-------------------
1 files changed, 23 insertions(+), 19 deletions(-)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 0c0ada9..a2edfb1 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2747,6 +2747,7 @@ x86_emulate_insn(struct x86_emulate_ctxt *ctxt)
int rc = X86EMUL_CONTINUE;
int saved_dst_type = c->dst.type;
int irq; /* Used for int 3, int, and into */
+ ulong old_eip;
Is never used.
Whoops.
@@ -3250,13 +3234,33 @@ writeback:
if (c->rep_prefix&& (c->d& String)) {
struct read_cache *rc =&ctxt->decode.io_read;
register_address_increment(c,&c->regs[VCPU_REGS_RCX], -1);
+ /* The second termination condition only applies for REPE
+ * and REPNE. Test if the repeat string operation prefix is
+ * REPE/REPZ or REPNE/REPNZ and if it's the case it tests the
+ * corresponding termination condition according to:
+ * - if REPE/REPZ and ZF = 0 then done
+ * - if REPNE/REPNZ and ZF = 1 then done
+ */
+ if ((c->b == 0xa6) || (c->b == 0xa7) ||
+ (c->b == 0xae) || (c->b == 0xaf)) {
+ trace_printk("c->eip %lx ctxt->eip %lx\n",
+ c->eip, ctxt->eip);
+ if (((c->rep_prefix == REPE_PREFIX)&&
+ ((ctxt->eflags& EFLG_ZF) == 0))
+ || ((c->rep_prefix == REPNE_PREFIX)&&
+ ((ctxt->eflags& EFLG_ZF) == EFLG_ZF))) {
+ ctxt->restart = false;
Why not jump to string_done label here?
It does a 'goto done;' which skips a couple of things.
+ }
+ }
/*
* Re-enter guest when pio read ahead buffer is empty or,
* if it is not used, after each 1024 iteration.
*/
if ((rc->end == 0&& !(c->regs[VCPU_REGS_RCX]& 0x3ff)) ||
- (rc->end != 0&& rc->end == rc->pos))
+ (rc->end != 0&& rc->end == rc->pos)) {
ctxt->restart = false;
+ c->eip = ctxt->eip;
We can get here when instruction is completed by above "if", so same
instruction will reexecute once again.
Not good. Will redo (and write tests).
--
error compiling committee.c: too many arguments to function
--
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