Hello,
I am trying to understand the causes of the vcpu xstate restore error during
live migration.
I get the following error during live migration:
xc: error: Failed to set vcpu0's xsave info (22 = Invalid argument): Internal
error
I was able to locate the failure point to the file xen/ar
- Original Message -
> From: "Andrew Cooper"
> To: "Fonyuy-Asheri Caleb" , "xen-devel"
>
> Sent: Thursday, July 11, 2024 12:45:18 PM
> Subject: Re: Help with Understanding vcpu xstate restore error during vm
> migration
> On 11/07
>> Please do you mind giving me more insight on the logic currently implemented
>> and maybe what is wrong with it? It will be important for me since what I'm
>> doing is research work.
>
> See 9e6dbbe8bf40^..267122a24c49
What reference is this please?
>
>> How do the values evc->size and xf
- Original Message -
> From: "Andrew Cooper"
> To: "Fonyuy-Asheri Caleb"
> Cc: "xen-devel" , "Jan Beulich"
> , "Roger Pau Monné"
>
> Sent: Thursday, July 11, 2024 3:04:05 PM
> Subject: Re: Help with Understanding
Hi Andrew,
>> I was able to locate the failure point to the file
>> xen/arch/x86/domctl.c with the following check.
>>
>> if( evc->size> evc->size>PV_XSAVE_SIZE(xfeature_mask) )
>> gotovcpuextstate_out;
>
> It is certainly more complicated than that.
>
> What that's saying is that Xen doesn't
>> PV Default policy: 30 leaves, 2 MSRs
>> ...
>> 000d: -> 0003::0240:
>> 000d:0001 -> 0007:::
>
> ... PV guests get nothing, while you're trying to migrate in a guest
> which...
>
>> =
- Original Message -
> From: "Jan Beulich"
> To: "Fonyuy-Asheri Caleb"
> Cc: "xen-devel" , "Andrew Cooper"
>
> Sent: Monday, July 15, 2024 10:16:07 AM
> Subject: Re: Help with Understanding vcpu xstate restore error during v
>>> On 15.07.2024 09:38, Fonyuy-Asheri Caleb wrote:
>>>>> Perhaps the more important question, are you booting the skylake with
>>>>> cpuid=no-avx on the command line by any chance?
>>>>
>>>> No. I didn't boot any of the machine
> On 15.07.2024 10:48, Fonyuy-Asheri Caleb wrote:
>>>>> On 15.07.2024 09:38, Fonyuy-Asheri Caleb wrote:
>>>>>>> Perhaps the more important question, are you booting the skylake with
>>>>>>> cpuid=no-avx on the command line by any chan
Hello Andrew,
Hello Jan,
Please permit me to come back to this once again.
> On 15/07/2024 9:16 am, Jan Beulich wrote:
>> On 15.07.2024 09:38, Fonyuy-Asheri Caleb wrote:
>>>> Perhaps the more important question, are you booting the skylake with
>>>> cpuid=
> If what you say in the earlier paragraph was the case with upstream Xen and
> without you restricting what the guest being migrated was able to see on the
> source host, then I think that would indicate a bug somewhere. Yet you don't
> provide enough details to be certain.
>
> Jan
Sorry for not
> On 06.08.2024 09:34, Fonyuy-Asheri Caleb wrote:
>>> If what you say in the earlier paragraph was the case with upstream Xen and
>>> without you restricting what the guest being migrated was able to see on the
>>> source host, then I think that would indicate
>
> None of these require extra state (i.e. registers), hence ...
>
>> Per my current understanding, I would expect more xstates on the VM than
>> supported on the target
>> server and hence a failure with xstate verification when restoring CPU state.
>
> ... no extra "xstates" (as you name it).
Hi,
I am currently doing a study on the way xen handles CPUID information.
I came across these constants in the code (xen/include/xen/lib/x86/cpu-policy.h
file) but no explanation of why they have been set that way.
#define CPUID_GUEST_NR_BASIC (0xdu + 1)
#define CPUID_GUEST_NR_CACHE (5u + 1
> From: "Roger Pau Monné"
> To: "Fonyuy-Asheri Caleb"
> Cc: "xen-devel"
> Sent: Monday, May 6, 2024 10:34:20 AM
> Subject: Re: file xen/include/xen/lib/x86/cpu-policy.h: Meaning of CPUID
> constants
> On Mon, May 06, 2024 at 09:46:58
Hello,
I am interested in finding understanding how xen handles CPUID faulting and
VM exits in general. Please can someone indicate to me the concerned files?
I want to know how xen detects the execution of the CPUID instruction and
ensures a guest only gets the features defined in cpuid-auto
Thank you
Caleb
- Original Message -
> From: "Andrew Cooper"
> To: "Fonyuy-Asheri Caleb" , "xen-devel"
>
> Cc: "Jan Beulich"
> Sent: Friday, January 3, 2025 3:35:43 PM
> Subject: Re: Help With Identifying CPUID faulting logic
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