On 08/17/2010 12:27 PM, Gleb Natapov wrote:
On Tue, Aug 17, 2010 at 12:20:34PM +0300, Avi Kivity wrote:
  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.

The only thing it skips is:
ctxt->decode.mem_read.end = 0;
as far as I can see. And this is ok if instruction is completed.

I'd like to avoid this interdependency (and there are enough gotos in the emulator already).


--
error compiling committee.c: too many arguments to function

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