# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1213611857 -3600
# Node ID 049a42108c65d9e56d18539454d49bc83f66eca2
# Parent ac745ad5f018356b4cf4b1ba127e6c2cc42c4723
x86_emulate: Fix the segment-load function
Fix the non-conforming type check and uses the consistent method to
fetch the cpl value as function get_cpl().
Also make sure vm86 mode is properly handled when determining whether
in real mode or protected mode -- in various respects vm86 mode can
act like both.
Signed-off-by: Dongxiao Xu <dongxiao.xu@xxxxxxxxx>
Signed-off-by: Keir Fraser <keir.fraser@xxxxxxxxxx>
---
xen/arch/x86/x86_emulate/x86_emulate.c | 30 +++++++++++++++++++-----------
1 files changed, 19 insertions(+), 11 deletions(-)
diff -r ac745ad5f018 -r 049a42108c65 xen/arch/x86/x86_emulate/x86_emulate.c
--- a/xen/arch/x86/x86_emulate/x86_emulate.c Fri Jun 13 16:10:50 2008 +0100
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c Mon Jun 16 11:24:17 2008 +0100
@@ -878,6 +878,14 @@ in_realmode(
}
static int
+in_protmode(
+ struct x86_emulate_ctxt *ctxt,
+ struct x86_emulate_ops *ops)
+{
+ return !(in_realmode(ctxt, ops) || (ctxt->regs->eflags & EFLG_VM));
+}
+
+static int
realmode_load_seg(
enum x86_segment seg,
uint16_t sel,
@@ -903,7 +911,7 @@ protmode_load_seg(
struct x86_emulate_ctxt *ctxt,
struct x86_emulate_ops *ops)
{
- struct segment_register desctab, cs, segr;
+ struct segment_register desctab, ss, segr;
struct { uint32_t a, b; } desc;
unsigned long val;
uint8_t dpl, rpl, cpl;
@@ -923,7 +931,7 @@ protmode_load_seg(
if ( (seg == x86_seg_ldtr) && (sel & 4) )
goto raise_exn;
- if ( (rc = ops->read_segment(x86_seg_cs, &cs, ctxt)) ||
+ if ( (rc = ops->read_segment(x86_seg_ss, &ss, ctxt)) ||
(rc = ops->read_segment((sel & 4) ? x86_seg_ldtr : x86_seg_gdtr,
&desctab, ctxt)) )
return rc;
@@ -955,7 +963,7 @@ protmode_load_seg(
dpl = (desc.b >> 13) & 3;
rpl = sel & 3;
- cpl = cs.sel & 3;
+ cpl = ss.attr.fields.dpl;
switch ( seg )
{
@@ -964,7 +972,7 @@ protmode_load_seg(
if ( !(desc.b & (1u<<11)) )
goto raise_exn;
/* Non-conforming segment: check DPL against RPL. */
- if ( ((desc.b & (6u<<9)) != 6) && (dpl != rpl) )
+ if ( ((desc.b & (6u<<9)) != (6u<<9)) && (dpl != rpl) )
goto raise_exn;
break;
case x86_seg_ss:
@@ -984,7 +992,7 @@ protmode_load_seg(
if ( (desc.b & (5u<<9)) == (4u<<9) )
goto raise_exn;
/* Non-conforming segment: check DPL against RPL and CPL. */
- if ( ((desc.b & (6u<<9)) != 6) && ((dpl < cpl) || (dpl < rpl)) )
+ if ( ((desc.b & (6u<<9)) != (6u<<9)) && ((dpl < cpl) || (dpl <
rpl)) )
goto raise_exn;
break;
}
@@ -1034,10 +1042,10 @@ load_seg(
(ops->write_segment == NULL) )
return X86EMUL_UNHANDLEABLE;
- if ( in_realmode(ctxt, ops) )
- return realmode_load_seg(seg, sel, ctxt, ops);
-
- return protmode_load_seg(seg, sel, ctxt, ops);
+ if ( in_protmode(ctxt, ops) )
+ return protmode_load_seg(seg, sel, ctxt, ops);
+
+ return realmode_load_seg(seg, sel, ctxt, ops);
}
void *
@@ -1596,7 +1604,7 @@ x86_emulate(
dst.val = (dst.val & ~3) | (src_val & 3);
else
dst.type = OP_NONE;
- generate_exception_if(in_realmode(ctxt, ops), EXC_UD, -1);
+ generate_exception_if(!in_protmode(ctxt, ops), EXC_UD, -1);
}
break;
@@ -3212,7 +3220,7 @@ x86_emulate(
if ( modrm == 0xdf ) /* invlpga */
{
- generate_exception_if(in_realmode(ctxt, ops), EXC_UD, -1);
+ generate_exception_if(!in_protmode(ctxt, ops), EXC_UD, -1);
generate_exception_if(!mode_ring0(), EXC_GP, 0);
fail_if(ops->invlpg == NULL);
if ( (rc = ops->invlpg(x86_seg_none, truncate_ea(_regs.eax),
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