From mboxrd@z Thu Jan  1 00:00:00 1970
From: yandong han <toyandong@gmail.com>
Subject: how to set VM into debug mode ? what are
	xmx_entry_helper for?
Date: Fri, 10 May 2013 14:09:39 +0800
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hi,all
I have three problems,anyone can solve them or one of them or give me some
clue? thank you

(1)  first, I want to know what job  xmx_entry_helper   does?
(2) second , whether every VMENTRY will call xmx_entry_helper   ?if not,
which function  will VMENTRY call  everytime?
(3)my target is setting VM into debug mode  by set Trag_flag,  the code
below  called vmx_properly_set_trap_flag,
and I add it at the end of vmx_vmexit_handler(). but it does not work.







 inline void vmx_properly_set_trap_flag(struct vcpu *v)
1301 {
1302     /* we are currently stepping, so we need to set the trap flag
1303     * on the next instruction
1304     */
1305     unsigned long int_state = __vmread(GUEST_INTERRUPTIBILITY_INFO);
1306     unsigned long activity_state = __vmread(GUEST_ACTIVITY_STATE);
1307
1308     unsigned long intercepts = __vmread(EXCEPTION_BITMAP);
1309     unsigned long mask = (1UL << TRAP_debug );
1310
1311     unsigned long flags = __vmread(GUEST_RFLAGS);
1312     unsigned long flags_mask = (X86_EFLAGS_TF);
1313
1314     /* make sure the exception bitmap says to vmexit on
1315      * debug exceptions
1316      */
1317     intercepts |= mask;
1318     __vmwrite(EXCEPTION_BITMAP, intercepts);
1319
1320     /* Default to setting trap flag to on */
1321     flags |= flags_mask;
1322
1323     if((activity_state == 1))
1324     {
1325
1326         /* this means we're in HLT mode. Disabling is OK since
1327         ** we will get an NMI to get out of HLT.
1328         ** The NMI will cause a VMExit which will reset TF
1329         ** execution
1330         **/
1331         printk("Turning off SS due to HLT\n");
1332         //flags &= ~(flags_mask);
1333     }
1334
1335     if((int_state & 3) )
1336     {
1337         int_state &= ~(3);
1338         printk("init_state is 3\n");
1339         //__vmwrite(GUEST_INTERRUPTIBILITY_INFO, int_state);
1340     }
1342     /* setting TF due to stepping enabled;*/
1343     __vmwrite(GUEST_RFLAGS, flags);
1344
1345 }



thank you , hope for your help
-- 
----------------------------------------------------------
regards,
yandong

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<div dir=3D"ltr"><div><br></div><div style>hi,all</div><div style>I have th=
ree problems,anyone can solve them or one of them or give me some clue? tha=
nk you</div><div style><br></div><div>(1) =A0first, I want to know what job=
 =A0xmx_entry_helper =A0 does?</div>
<div style>(2) second , whether every VMENTRY will call xmx_entry_helper =
=A0 ?if not, which function =A0will VMENTRY call =A0everytime?</div><div st=
yle>(3)my target is setting VM into debug mode =A0by set Trag_flag, =A0the =
code below =A0called vmx_properly_set_trap_flag,=A0</div>
<div style>and I add it at the end of vmx_vmexit_handler(). but it does not=
 work.</div><div style><br></div><div style><br></div><div style><br></div>=
<div style><br></div><div style><br></div><div style><br></div><div style>
<br></div><div style><div>=A0inline void vmx_properly_set_trap_flag(struct =
vcpu *v)</div><div>1301 {</div><div>1302 =A0 =A0 /* we are currently steppi=
ng, so we need to set the trap flag</div><div>1303 =A0 =A0 * on the next in=
struction</div>
<div>1304 =A0 =A0 */</div><div>1305 =A0 =A0 unsigned long int_state =3D __v=
mread(GUEST_INTERRUPTIBILITY_INFO);</div><div>1306 =A0 =A0 unsigned long ac=
tivity_state =3D __vmread(GUEST_ACTIVITY_STATE);</div><div>1307</div><div>1=
308 =A0 =A0 unsigned long intercepts =3D __vmread(EXCEPTION_BITMAP);</div>
<div>1309 =A0 =A0 unsigned long mask =3D (1UL &lt;&lt; TRAP_debug );</div><=
div>1310</div><div>1311 =A0 =A0 unsigned long flags =3D __vmread(GUEST_RFLA=
GS);</div><div>1312 =A0 =A0 unsigned long flags_mask =3D (X86_EFLAGS_TF);</=
div><div>1313</div>
<div>1314 =A0 =A0 /* make sure the exception bitmap says to vmexit on</div>=
<div>1315 =A0 =A0 =A0* debug exceptions</div><div>1316 =A0 =A0 =A0*/</div><=
div>1317 =A0 =A0 intercepts |=3D mask;</div><div>1318 =A0 =A0 __vmwrite(EXC=
EPTION_BITMAP, intercepts);</div>
<div>1319</div><div>1320 =A0 =A0 /* Default to setting trap flag to on */</=
div><div>1321 =A0 =A0 flags |=3D flags_mask;</div><div>1322</div><div>1323 =
=A0 =A0 if((activity_state =3D=3D 1))</div><div>1324 =A0 =A0 {</div><div>13=
25</div><div>1326 =A0 =A0 =A0 =A0 /* this means we&#39;re in HLT mode. Disa=
bling is OK since</div>
<div>1327 =A0 =A0 =A0 =A0 ** we will get an NMI to get out of HLT.</div><di=
v>1328 =A0 =A0 =A0 =A0 ** The NMI will cause a VMExit which will reset TF</=
div><div>1329 =A0 =A0 =A0 =A0 ** execution</div><div>1330 =A0 =A0 =A0 =A0 *=
*/</div><div>1331 =A0 =A0 =A0 =A0 printk(&quot;Turning off SS due to HLT\n&=
quot;);</div>
<div>1332 =A0 =A0 =A0 =A0 //flags &amp;=3D ~(flags_mask);</div><div>1333 =
=A0 =A0 }</div><div>1334</div><div>1335 =A0 =A0 if((int_state &amp; 3) )</d=
iv><div>1336 =A0 =A0 {</div><div>1337 =A0 =A0 =A0 =A0 int_state &amp;=3D ~(=
3);</div><div>1338 =A0 =A0 =A0 =A0 printk(&quot;init_state is 3\n&quot;);</=
div>
<div>1339 =A0 =A0 =A0 =A0 //__vmwrite(GUEST_INTERRUPTIBILITY_INFO, int_stat=
e);</div><div>1340 =A0 =A0 }</div><div><div>1342 =A0 =A0 /* setting TF due =
to stepping enabled;*/</div><div>1343 =A0 =A0 __vmwrite(GUEST_RFLAGS, flags=
);</div><div>1344</div>
<div>1345 }</div></div></div><div style><br></div><div><br></div><br clear=
=3D"all"><div style>thank you , hope for your help=A0</div>-- <br><div dir=
=3D"ltr"><span>------------------------------</span><span>-----------------=
-----------</span><br>
regards,<div><div>yandong<br><br></div></div></div>
</div>

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