[PATCH v11 00/43] KVM: arm64: Nested Virtualization support (FEAT_NV2 only)

[Ganapatrao Kulkarni]

On 21-11-2023 02:38 pm, Marc Zyngier wrote:
> On Tue, 21 Nov 2023 08:51:35 +0000,
> Ganapatrao Kulkarni <gankulkarni at os.amperecomputing.com> wrote:
>>
>>
>> Hi Marc,
>>
>> On 20-11-2023 06:39 pm, Marc Zyngier wrote:
>>> This is the 5th drop of NV support on arm64 for this year, and most
>>> probably the last one for this side of Christmas.
>>>
>>> For the previous episodes, see [1].
>>>
>>> What's changed:
>>>
>>> - Drop support for the original FEAT_NV. No existing hardware supports
>>>     it without FEAT_NV2, and the architecture is deprecating the former
>>>     entirely. This results in fewer patches, and a slightly simpler
>>>     model overall.
>>>
>>> - Reorganise the series to make it a bit more logical now that FEAT_NV
>>>     is gone.
>>>
>>> - Apply the NV idreg restrictions on VM first run rather than on each
>>>     access.
>>>
>>> - Make the nested vgic shadow CPU interface a per-CPU structure rather
>>>     than per-vcpu.
>>>
>>> - Fix the EL0 timer fastpath
>>>
>>> - Work around the architecture deficiencies when trapping WFI from a
>>>     L2 guest.
>>>
>>> - Fix sampling of nested vgic state (MISR, ELRSR, EISR)
>>>
>>> - Drop the patches that have already been merged (NV trap forwarding,
>>>     per-MMU VTCR)
>>>
>>> - Rebased on top of 6.7-rc2 + the FEAT_E2H0 support [2].
>>>
>>> The branch containing these patches (and more) is at [3]. As for the
>>> previous rounds, my intention is to take a prefix of this series into
>>> 6.8, provided that it gets enough reviewing.
>>>
>>> [1] https://lore.kernel.org/r/20230515173103.1017669-1-maz@kernel.org
>>> [2] https://lore.kernel.org/r/20231120123721.851738-1-maz@kernel.org
>>> [3] https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git/log/?h=kvm-arm64/nv-6.8-nv2-only
>>>
>>
>> V11 series is not booting on Ampere platform (I am yet to debug).
>> With lkvm, it is stuck at the very early stage itself and no early
>> boot prints/logs.
>>
>> Are there any changes needed in kvmtool for V11?
> 
> Not really, I'm still using the version I had built for 6.5. Is the
> problem with L1 or L2?

Stuck in the L1 itself.

I am using kvmtool from 
https://git.kernel.org/pub/scm/linux/kernel/git/maz/kvmtool.git/log/?h=arm64/nv-5.16

> 
> However, this looks like a problem I've been chasing, and which I
> though was only a M2 issue. In some situations, I'm getting interrupt
> storms when L1 gets a level interrupt while in L2.
> 
> Can you cherry-pick [1] from my tree, and let me know if this helps?
> This isn't a proper fix, but if L2 starts booting with this, I would
> know this is a common issue.
> 
> Now, if your problem is with L1, I really have no idea.
> 
> Thanks,
> 
> 	M.
> 
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git/commit/?h=kvm-arm64/nv-6.8-nv2-only&id=759d2e18f8954f4c76eb1772f38301df6ed8fa5d
> 

Thanks,
Ganapat