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Re: [PATCH v7] xen: allow up to 16383 cpus


  • To: Julien Grall <julien@xxxxxxx>, Juergen Gross <jgross@xxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxxx
  • From: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
  • Date: Fri, 10 May 2024 22:11:23 +0100
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  • Cc: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>, Community Manager <community.manager@xxxxxxxxxxxxxx>, George Dunlap <george.dunlap@xxxxxxxxxx>, Jan Beulich <jbeulich@xxxxxxxx>, Stefano Stabellini <sstabellini@xxxxxxxxxx>
  • Delivery-date: Fri, 10 May 2024 21:11:35 +0000
  • List-id: Xen developer discussion <xen-devel.lists.xenproject.org>

On 10/05/2024 10:08 pm, Julien Grall wrote:
> Hi Juergen,
>
> On 10/05/2024 15:16, Juergen Gross wrote:
>> With lock handling now allowing up to 16384 cpus (spinlocks can handle
>> 65535 cpus, rwlocks can handle 16384 cpus), raise the allowed limit for
>> the number of cpus to be configured to 16383.
>>
>> The new limit is imposed by IOMMU_CMD_BUFFER_MAX_ENTRIES and
>> QINVAL_MAX_ENTRY_NR required to be larger than 2 * CONFIG_NR_CPUS.
>>
>> Add a support limit of physical CPUs to SUPPORT.md (4096 on x86, 128
>> on ARM).
>>
>> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
>> Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
>
> I am a bit surprised that this is kept given you added SUPPORT.md. I'd
> like Jan (or other x86 maintainers) to confirm they are happy with the
> proposed x86 security supported limit the SUPPORT.md.
>
> For Arm (only):
>
> Acked-by: Julien Grall <jgrall@xxxxxxxxxx>

XenServer is currently at 2k and we're waiting on this series to move to 4k.

I'm happy with this being the security statement for now.

~Andrew



 


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