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Re: [PATCH] x86: kexec is PV-only


  • To: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
  • From: Jan Beulich <jbeulich@xxxxxxxx>
  • Date: Tue, 30 Jun 2026 15:42:05 +0200
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  • Cc: Roger Pau Monné <roger.pau@xxxxxxxxxx>, Teddy Astie <teddy.astie@xxxxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxxx>
  • Delivery-date: Tue, 30 Jun 2026 13:42:15 +0000
  • List-id: Xen developer discussion <xen-devel.lists.xenproject.org>

On 30.06.2026 15:37, Andrew Cooper wrote:
> On 30/06/2026 2:35 pm, Jan Beulich wrote:
>> Kexec is of no use without its hypercall, and that hypercall is wired up
>> only for PV. Allowing that code to be built when !PV therefore results in
>> a lot of unreachable code, violating Misra C:2012 rule 2.1.
>>
>> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
>>
>> --- a/xen/arch/x86/Kconfig
>> +++ b/xen/arch/x86/Kconfig
>> @@ -22,7 +22,7 @@ config X86
>>      select HAS_EX_TABLE
>>      select HAS_FAST_MULTIPLY
>>      select HAS_IOPORTS
>> -    select HAS_KEXEC
>> +    select HAS_KEXEC if PV
>>      select HAS_NS16550
>>      select HAS_PASSTHROUGH
>>      select HAS_PCI
> 
> This might be true, but it's wrong.  kexec should be wired up for PVH
> too, and I don't see any reason why it can't be.

I'm happy to drop this patch if one enabling PVH surfaces. I did point out
the issue a little while back, and since nothing really happened, I thought
I'd make this patch to at least address the Misra aspect. I just don't see
myself audit the affected code paths for validity in the PVH case.

Jan



 


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