Ugh! Sorry that got munged. Let me try again:
(XEN) hvmop_emulate_realmode
(XEN) guest requests real mode emulation
(XEN) foo 221
(XEN) eip = 0xd338d
(XEN) eip = 0xd338e
(XEN) eip = 0xffbf0000
(XEN) failed to emulate instruction at %eip = 0xd338d
(XEN) domain_crash_sync called from vmcs.c:625
(XEN) Domain 1 (vcpu#0) crashed on cpu#0:
(XEN) ----[ Xen-3.0-unstable x86_32 debug=n Not tainted ]----
(XEN) CPU: 0
(XEN) EIP: 0010:[<000d338d>]
(XEN) EFLAGS: 00000002 CONTEXT: hvm
(XEN) eax: 00000076 ebx: 000d7324 ecx: 000d7324 edx: 000000e9
(XEN) esi: 000d4e54 edi: 000d3380 ebp: 000d72a8 esp: 000d72a8
(XEN) cr0: 00050032 cr4: 00000651 cr3: 00000000 cr2: 00000000

Regards,
Anthony Liguori
Anthony Liguori wrote:

Kamble, Nitin A wrote:

Hi Anthony,

With the new revision I am able to get the -emulate-16bit command line switch working. (XEN) HVM2: Creating MP tables ... (XEN) HVM2: Loading Cirrus VGABIOS ... (XEN) HVM2: Loading ACPI ... (XEN) HVM2: Loading VMXAssist ... deadbeef (XEN) HVM2: foo (XEN) hvmop_emulate_realmode (XEN) guest requests real mode emulation (XEN) foo 221 (XEN) HVM2: Invoking ROMBIOS ... (XEN) hvm.c:446:d2 Triple fault on VCPU0 - invoking HVM system reset.

The Triple fault you're seeing here is terribly curious. Also the "deadbeef" output. Just to sanity check, I threw the following printk in vmcs.c

 while (!hypercall_preempt_check()) {
+ printk("eip = 0x%x\n", regs->eip);
 if (x86_emulate(&ctxt, &em_ops)) {
And I get the following output with a FC5 guest:

(XEN) hvmop_emulate_realmode (XEN) guest requests real mode emulation (XEN) foo 221 (XEN) eip = 0xd338d (XEN) eip = 0xd338e (XEN) eip = 0xffbf0000 (XEN) failed to emulate instruction at %eip = 0xd338d (XEN) domain_crash_sync called from vmcs.c:625 (XEN) Domain 1 (vcpu#0) crashed on cpu#0: (XEN) ----[ Xen-3.0-unstable x86_32 debug=n Not tainted ]---- (XEN) CPU: 0 (XEN) EIP: 0010:[<000d338d>] (XEN) EFLAGS: 00000002 CONTEXT: hvm (XEN) eax: 00000076 ebx: 000d7324 ecx: 000d7324 edx: 000000e9 (XEN) esi: 000d4e54 edi: 000d3380 ebp: 000d72a8 esp: 000d72a8 (XEN) cr0: 00050032 cr4: 00000651 cr3: 00000000 cr2: 00000000 (XEN) ds: 0000 es: 0000 fs: 0000 gs: 0000 ss: 0018 cs: 0010 So, perhaps it's the guest you're using? Clearly, we're running in x86_emulate and hitting a 16 bit instruction we can't handle. N.B. the printk in the error path for x86_emulate is wrong. I should be looking at regs->eip, not GUEST_RIP since that wouldn't have been updated again.

Regards,
Anthony Liguori

I have not added any debug lines in the code yet, and I don't know how far is the emulator going. I will check it tomorrow.

Thanks & Regards,
Nitin
Open Source Technology Center, Intel Corporation.

-------------------------------------------------------------------------

The mind is like a parachute; it works much better when it's open.
On Thu, 2007年03月29日 at 17:59 -0700, Nitin A Kamble wrote:

On Thu, 2007年03月29日 at 19:11 -0500, Anthony Liguori wrote:

Okay, you'll need to make sure that hvmloader and qemu are both being rebuilt and reinstalled.

I am sure both are built with the patch and installed correctly.

The really curious thing is that eip from the VMCS is set to 0. eip should be address of the EIP of whatever movl cr0 instruction that occurs when returning from main() in hvmloader.

I also find that x86_emulate() is never called while emulate_realmode is set in the hypervisor.

I guess it's possible that if you are using a version of unstable that predates Keir's recent hvmloader changes, you wouldn't have hvmloader switching to real mode. That could explain some of the weirdness you're seeing. What changeset are you on?

So far I am using: r14560_20070326
Now I am trying with: r14631_20070329
Thanks & Regards,
Nitin
Open Source Technology Center, Intel Corporation.

-------------------------------------------------------------------------

The mind is like a parachute; it works much better when it's open.

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