[Xen-devel] [PATCH] creating HVM(Intel VT) on X86_32 crashes Xen

[Kouya SHIMURA <kouya@xxxxxxxxxxxxxx>]

I met Xen crashed when I create a HVM(Intel VT) guest on 32bit system.
Attached log is from Xen console. My environment is:

Changeset:   13091:f80f1cc7f85e
Processor:   Intel Core Duo(T2600, not Core2), i.e. 32bit guest/host.

This bug seems to be inserted by #Cset 12480:6a26f49d3b16.
Attached patch fixes it.

Thanks,
Kouya

Signed-off-by: Kouya Shimura <kouya@xxxxxxxxxxxxxx>

(XEN) ----[ Xen-3.0-unstable  x86_32  debug=n  Not tainted ]----
(XEN) CPU:    1
(XEN) EIP:    e008:[<ff14c385>] vmx_ctxt_switch_from+0x15/0xa0
(XEN) EFLAGS: 00010092   CONTEXT: hypervisor
(XEN) eax: ff18d280   ebx: ffbe1080   ecx: c0000102   edx: 00000001
(XEN) esi: ffbf3ff8   edi: ffbe13c8   ebp: ffbf6080   esp: ffbf3f08
(XEN) cr0: 8005003b   cr4: 000026d0   cr3: 6237d000   cr2: 00000000
(XEN) ds: e010   es: e010   fs: e010   gs: e010   ss: e010   cs: e008
(XEN) Xen stack trace from esp=ffbf3f08:
(XEN)    ff1a37c4 00000000 ffbf3fb4 ff11e966 ffbe1080 c4cd6357 ff114a4a ff18c320
(XEN)    00001000 00000001 ffbe1080 ffbe1d04 ffbe1080 ff1a2080 ff142b08 00000001
(XEN)    00000092 ffbf6080 00000000 ff11eab9 ff18d280 ffbf3fb4 ffbf3fb4 ff12e6e7
(XEN)    01c9c380 00000000 ff14aa7d ff122ae6 ffbf3f7c ffbf3fb4 00000001 00000000
(XEN)    ffbf3fb4 ffbf6080 00000000 00000000 00fd0000 ff11e72e 0000e008 00000246
(XEN)    00060a44 ffbe1080 000002f4 00060a14 00000007 00307ae3 00000000 00060b9f
(XEN)    00060a44 00050032 00000000 00100000 00000000 00000000 00000000 00000000
(XEN)    00000000 00000000 00000000 00000000 00000001 ffbf6080
(XEN) Xen call trace:
(XEN)    [<ff14c385>] vmx_ctxt_switch_from+0x15/0xa0
(XEN)    [<ff11e966>] __context_switch+0x86/0x1a0
(XEN)    [<ff114a4a>] schedule+0x19a/0x2c0
(XEN)    [<ff142b08>] cpu_has_pending_irq+0x48/0x70
(XEN)    [<ff11eab9>] __sync_lazy_execstate+0x39/0x50
(XEN)    [<ff12e6e7>] smp_invalidate_interrupt+0x27/0x70
(XEN)    [<ff14aa7d>] vmx_intr_assist+0x4d/0x320
(XEN)    [<ff122ae6>] invalidate_interrupt+0x46/0x50
(XEN)    [<ff11e72e>] idle_loop+0x4e/0x70
(XEN)    
(XEN) 
(XEN) ****************************************
(XEN) Panic on CPU 1:
(XEN) FATAL TRAP: vector = 13 (general protection fault)
(XEN) [error_code=0000] , IN INTERRUPT CONTEXT
(XEN) ****************************************
(XEN) 
(XEN) Reboot in five seconds...

diff -r f80f1cc7f85e xen/arch/x86/hvm/vmx/vmx.c
--- a/xen/arch/x86/hvm/vmx/vmx.c        Wed Dec 20 09:48:21 2006 +0000
+++ b/xen/arch/x86/hvm/vmx/vmx.c        Thu Dec 21 13:07:41 2006 +0900
@@ -374,9 +374,11 @@ static void vmx_ctxt_switch_from(struct 
 {
     hvm_freeze_time(v);
 
+#ifdef __x86_64__
     /* NB. MSR_SHADOW_GS_BASE may be changed by swapgs instrucion in guest,
      * so we must save it. */
     rdmsrl(MSR_SHADOW_GS_BASE, v->arch.hvm_vmx.msr_state.shadow_gs);
+#endif
 
     vmx_restore_host_msrs();
     vmx_save_dr(v);

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