Re: [PATCH v6 0/7] KVM: arm64: nv: Implement nested stage-2 reverse map

On Thu, Sep 17, 2026 at 03:51:19PM +0900, Itaru Kitayama wrote:

On Wed, Sep 16, 2026 at 08:08:20AM +0100, Marc Zyngier wrote:

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On Wed, 16 Sep 2026 00:27:22 +0100,
Itaru Kitayama [off-list ref] wrote:

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On Wed, Sep 16, 2026 at 12:22:30AM +0100, Wei-Lin Chang wrote:

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On Wed, Sep 16, 2026 at 06:49:57AM +0900, Itaru Kitayama wrote:

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On Tue, Sep 15, 2026 at 04:42:58PM +0100, Wei-Lin Chang wrote:

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Hi,

This is v6 of optimizing the shadow s2 mmu unmapping during MMU
notifiers.

This version fixes a few issues, and adds Marc's space optimization
for kvm_guest_s2_mapping [1]. Please see the changelog for the details.

Tested by booting L3, and running in-kernel targetted tests described
in [2]. v5 got some tested-by's from Itaru and Wang (thanks), I didn't
carry them over since some bugs fixed in v6 are non-obvious. Some
retest would be much appreciated!

How did you boot into L3, with KVM selftest or recrusively boot on HW?

I just recrusively booted VMs on hardware. :)

Good. Then I actually tried that on Grace CPUs, but letting L1 boot 
with nested mode did not print "VHE+NV2" KVM init log in dmesg, thus not
able to boot L3. Do I need to add other than kvm.arm-mode=nested to command line?

kvm-arm.mode=nested, as documented. That also puts in perspective your
TB tag on the whole series...

Yes. Using kvmtool's --nested option did not bring vCPU with the VHE+NV2 boot
log. The Host kernel is Wei-Lin's version 6 booted on Grace CPUs, and
the guest kernel is today's kvmarm/fixes plus Wei-Lin's shadow stage 2 ptdump fix.

I'm not sure what you did exactly, but just to be clear, you need to
pass kvm-arm.mode=nested to L1's command line as well, in addition to
kvmtool's --nested option.

./lkvm run --nested -p kvm-arm.mode=nested <...>

Thanks,
Wei-Lin Chang

Thanks,
Itaru.

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	M.


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