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

[Marc Zyngier]

On Tue, 21 Nov 2023 09:26:22 +0000,
Ganapatrao Kulkarni <gankulkarni at os.amperecomputing.com> wrote:
> 
> 
> 
> 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

Huh. That's positively ancient. Yet, you shouldn't get into a
situation where the L1 guest locks up.

I have pushed out my kvmtool branch[1]. Please give it a go.

Thanks,

	M.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/maz/kvmtool.git/log/?h=arm64/nv-6.5

-- 
Without deviation from the norm, progress is not possible.