Re: [Xen-users] Domu windows 2012 crash.

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 18/03/2020 15:32, Johnny Ström wrote:
> On 3/14/20 2:54 PM, Hans van Kranenburg wrote:
>> Hi Johnny,
>>
>> On 2/20/20 10:10 AM, johnny Strom wrote:
>>> After the latest updates/security updates for debian 9 and debian 10,
>>> so will windows 2012 crash if more than 4096 memory is available to
>>> domu.
>> I am able to reproduce this with a Windows server essentials 2019 HVM
>> domU.
>>
>> An example from xl dmesg:
>>
>> (XEN) Failed to shatter gfn 105245: -12
>> (XEN) d75v1 EPT violation 0x19c (--x/rw-) gpa 0x00000105245760 mfn
>> 0x285245 type 0
>> (XEN) d75v1 Walking EPT tables for GFN 105245:
>> (XEN) d75v1  epte 9c000004105f9007
>> (XEN) d75v1  epte 9c000002800000f3
>> (XEN) d75v1  --- GLA 0x7ff98b40d760
>> (XEN) domain_crash called from vmx.c:3497
>> (XEN) Domain 75 (vcpu#1) crashed on cpu#4:
>> (XEN) ----[ Xen-4.11.4-pre  x86_64  debug=n   Not tainted ]----
>> (XEN) CPU:    4
>> (XEN) RIP:    0033:[<00007ff98b40d760>]
>> (XEN) RFLAGS: 0000000000010216   CONTEXT: hvm guest (d75v1)
>> (XEN) rax: 0000000000001212   rbx: 000000c714d9da58   rcx:
>> 0000023500001590
>> (XEN) rdx: 000000c700000001   rsi: 000000c714d9da18   rdi:
>> 000000c714d9db20
>> (XEN) rbp: 000000c714d9d950   rsp: 000000c714d9d918   r8: 
>> 0000023500001470
>> (XEN) r9:  00000235000014f0   r10: 00007ff99c5c0923   r11:
>> 000000c714d9d970
>> (XEN) r12: 0000000000000000   r13: 000000c714d9d9d0   r14:
>> 000000c714d9da58
>> (XEN) r15: 0000000000000006   cr0: 0000000080050031   cr4:
>> 0000000000060678
>> (XEN) cr3: 00000001d9458002   cr2: 00007ff98b6fa048
>> (XEN) fsb: 0000000000000000   gsb: 000000c714e9e000   gss:
>> ffffcd015dc40000
>> (XEN) ds: 002b   es: 002b   fs: 0053   gs: 002b   ss: 002b   cs: 0033
>>
>>> So it's in debian 9 update: xen (4.8.5.final+shim4.10.4-1+deb9u12)
>>> and in debian 10 update:  xen (4.11.3+24-g14b62ab3e5-1) that is causing
>>> the crashes.
>> For 4.11, can you please try the workaround to enable "executable EPT
>> superpages" again?
>>
>> It's the ept=exec-sp hypervisor setting, and can also be set without
>> rebooting using:
>>
>>     xl set-parameters ept=exec-sp
>
>
> Hello
>
>
> I have been running test  with "xl set-parameters ept=exec-sp" and
> windows 2012 R2.
>
> And it dose not crash anymore.
>
> I used memory = 5120 that did make it crash within 2 minutes before.
>
> So xl set-parameters ept=exec-sp seems to be an workaround for now.

Right, but what you're doing is turning off the security fix for XSA-304.

Do you have any shadow_memory= option set in your VM's config file?  If
so, please remove it.

~Andrew

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