Re: [kvm-devel] [patch 2 of 2] Emulate CMPS instruction
On Fri, 23 Nov 2007 19:54:46 +0200
Avi Kivity <[EMAIL PROTECTED]> wrote:
>
> No new macros in the emulator please. Just inline it at the callsite.
>
Ok I make the modification.
: c->dst.bytes);
> > break;
> > case 0xa6 ... 0xa7: /* cmps */
> > - DPRINTF("Urk! I don't handle CMPS.\n");
> > - goto cannot_emulate;
> > + c->src.type = OP_NONE;
> >
>
> Shouldn't this be OP_MEM?
As bytes to be compared are just read I use OP_NONE to disable writeback.
>
> > + c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
> > + c->dst.ptr = (unsigned long *)register_address(
> > + ctxt->es_base,
> > + c->regs[VCPU_REGS_RSI]);
> > +
> > + DPRINTF("cmps: mem1=0x%p mem2=0x%p\n", c->src.ptr, c->dst.ptr);
> > +
> >
>
> Where is the actual memory access?
Oops I missed that point I fix that immediately.
Thanks for your help,
Guillaume
-
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Re: [kvm-devel] [patch 2 of 2] Emulate CMPS instruction
Guillaume Thouvenin wrote:
> This patch emulates the CMPS instruction.
>
> Signed-off-by: Guillaume Thouvenin <[EMAIL PROTECTED]>
> ---
>
> drivers/kvm/x86_emulate.c | 54
> +++--
> 1 files changed, 52 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/kvm/x86_emulate.c b/drivers/kvm/x86_emulate.c
> index cee60eb..db744cf 100644
> --- a/drivers/kvm/x86_emulate.c
> +++ b/drivers/kvm/x86_emulate.c
> @@ -445,6 +445,29 @@ static u16 twobyte_table[256] = {
> register_address_increment(c->eip, rel);\
> } while (0)
>
> +/* 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
> + */
> +#define handle_rep_prefix(c)\
> + do {\
> + if ((c->b == 0xa6) || (c->b == 0xa7) || \
> + (c->b == 0xae) || (c->b == 0xaf)) { \
> + if ((c->rep_prefix == REPE_PREFIX) && \
> + ((ctxt->eflags & EFLG_ZF) == 0)) { \
> + ctxt->vcpu->rip = c->eip; \
> + goto done; \
> + } \
> + if ((c->rep_prefix == REPNE_PREFIX) && \
> + ((ctxt->eflags & EFLG_ZF) == EFLG_ZF)) {\
> + ctxt->vcpu->rip = c->eip; \
> + goto done; \
> + } \
> + } \
> + } while (0)
> +
>
No new macros in the emulator please. Just inline it at the callsite.
> static int do_fetch_insn_byte(struct x86_emulate_ctxt *ctxt,
> struct x86_emulate_ops *ops,
> unsigned long linear, u8 *dest)
> @@ -1540,10 +1563,15 @@ special_insn:
> break;
> }
> if (c->rep_prefix) {
> + /* All REP prefixes have the same first termination condition */
> if (c->regs[VCPU_REGS_RCX] == 0) {
> ctxt->vcpu->rip = c->eip;
> goto done;
> }
> + /* The second termination condition only applies for REPE
> + * and REPNE. handle_rep_prefix() macro deals with that.
> + */
> + handle_rep_prefix(c);
> c->regs[VCPU_REGS_RCX]--;
> c->eip = ctxt->vcpu->rip;
> }
> @@ -1570,8 +1598,30 @@ special_insn:
> : c->dst.bytes);
> break;
> case 0xa6 ... 0xa7: /* cmps */
> - DPRINTF("Urk! I don't handle CMPS.\n");
> - goto cannot_emulate;
> + c->src.type = OP_NONE;
>
Shouldn't this be OP_MEM?
> + c->src.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
> + c->src.ptr = (unsigned long *)register_address(
> +ctxt->ds_base,
> +c->regs[VCPU_REGS_RDI]);
> +
> + c->dst.type = OP_NONE;
>
And here?
> + c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
> + c->dst.ptr = (unsigned long *)register_address(
> +ctxt->es_base,
> +c->regs[VCPU_REGS_RSI]);
> +
> + DPRINTF("cmps: mem1=0x%p mem2=0x%p\n", c->src.ptr, c->dst.ptr);
> +
>
Where is the actual memory access?
> + emulate_2op_SrcV("cmp", c->src, c->dst, ctxt->eflags);
> +
> + register_address_increment(c->regs[VCPU_REGS_RDI],
> +(ctxt->eflags & EFLG_DF) ? -c->dst.bytes
> + : c->dst.bytes);
> +
> + register_address_increment(c->regs[VCPU_REGS_RSI],
> +(ctxt->eflags & EFLG_DF) ? -c->dst.bytes
> + : c->dst.bytes);
> + break;
> case 0xaa ... 0xab: /* stos */
> c->dst.type = OP_MEM;
> c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
>
> -
> This SF.net email is sponsored by: Microsoft
> Defy all challenges. Microsoft(R) Visual Studio 2005.
> http://clk.atdmt.com/MRT/go/vse012070mrt/direct/01/
> ___
> kvm-devel
[kvm-devel] [patch 2 of 2] Emulate CMPS instruction
This patch emulates the CMPS instruction.
Signed-off-by: Guillaume Thouvenin <[EMAIL PROTECTED]>
---
drivers/kvm/x86_emulate.c | 54 +++--
1 files changed, 52 insertions(+), 2 deletions(-)
diff --git a/drivers/kvm/x86_emulate.c b/drivers/kvm/x86_emulate.c
index cee60eb..db744cf 100644
--- a/drivers/kvm/x86_emulate.c
+++ b/drivers/kvm/x86_emulate.c
@@ -445,6 +445,29 @@ static u16 twobyte_table[256] = {
register_address_increment(c->eip, rel);\
} while (0)
+/* 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
+ */
+#define handle_rep_prefix(c)\
+ do {\
+ if ((c->b == 0xa6) || (c->b == 0xa7) || \
+ (c->b == 0xae) || (c->b == 0xaf)) { \
+ if ((c->rep_prefix == REPE_PREFIX) && \
+ ((ctxt->eflags & EFLG_ZF) == 0)) { \
+ ctxt->vcpu->rip = c->eip; \
+ goto done; \
+ } \
+ if ((c->rep_prefix == REPNE_PREFIX) && \
+ ((ctxt->eflags & EFLG_ZF) == EFLG_ZF)) {\
+ ctxt->vcpu->rip = c->eip; \
+ goto done; \
+ } \
+ } \
+ } while (0)
+
static int do_fetch_insn_byte(struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops,
unsigned long linear, u8 *dest)
@@ -1540,10 +1563,15 @@ special_insn:
break;
}
if (c->rep_prefix) {
+ /* All REP prefixes have the same first termination condition */
if (c->regs[VCPU_REGS_RCX] == 0) {
ctxt->vcpu->rip = c->eip;
goto done;
}
+ /* The second termination condition only applies for REPE
+* and REPNE. handle_rep_prefix() macro deals with that.
+*/
+ handle_rep_prefix(c);
c->regs[VCPU_REGS_RCX]--;
c->eip = ctxt->vcpu->rip;
}
@@ -1570,8 +1598,30 @@ special_insn:
: c->dst.bytes);
break;
case 0xa6 ... 0xa7: /* cmps */
- DPRINTF("Urk! I don't handle CMPS.\n");
- goto cannot_emulate;
+ c->src.type = OP_NONE;
+ c->src.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
+ c->src.ptr = (unsigned long *)register_address(
+ ctxt->ds_base,
+ c->regs[VCPU_REGS_RDI]);
+
+ c->dst.type = OP_NONE;
+ c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
+ c->dst.ptr = (unsigned long *)register_address(
+ ctxt->es_base,
+ c->regs[VCPU_REGS_RSI]);
+
+ DPRINTF("cmps: mem1=0x%p mem2=0x%p\n", c->src.ptr, c->dst.ptr);
+
+ emulate_2op_SrcV("cmp", c->src, c->dst, ctxt->eflags);
+
+ register_address_increment(c->regs[VCPU_REGS_RDI],
+ (ctxt->eflags & EFLG_DF) ? -c->dst.bytes
+ : c->dst.bytes);
+
+ register_address_increment(c->regs[VCPU_REGS_RSI],
+ (ctxt->eflags & EFLG_DF) ? -c->dst.bytes
+ : c->dst.bytes);
+ break;
case 0xaa ... 0xab: /* stos */
c->dst.type = OP_MEM;
c->dst.bytes = (c->d & ByteOp) ? 1 : c->op_bytes;
-
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