From: Itaru Kitayama <itaru.kitayama@fujitsu•com>
To: Marc Zyngier <maz@kernel•org>
Cc: Wei-Lin Chang <weilin.chang@arm•com>,
linux-arm-kernel@lists•infradead.org, kvmarm@lists•linux.dev,
linux-kernel@vger•kernel.org, Oliver Upton <oupton@kernel•org>,
Joey Gouly <joey.gouly@arm•com>,
Suzuki K Poulose <suzuki.poulose@arm•com>,
Zenghui Yu <yuzenghui@huawei•com>,
Catalin Marinas <catalin.marinas@arm•com>,
Will Deacon <will@kernel•org>
Subject: Re: [PATCH v3 0/5] KVM: arm64: nv: Implement nested stage-2 reverse map
Date: Fri, 29 May 2026 09:55:24 +0900 [thread overview]
Message-ID: <ahjj_CKuXhDOHhBZ@sm-arm-grace07> (raw)
In-Reply-To: <86fr3bvnt5.wl-maz@kernel.org>
On Thu, May 28, 2026 at 11:19:34AM +0100, Marc Zyngier wrote:
> On Wed, 20 May 2026 08:31:12 +0100,
> Itaru Kitayama <itaru.kitayama@fujitsu•com> wrote:
> >
> > Hi Wei Lin,
> >
> > On Sun, May 10, 2026 at 03:53:33PM +0100, Wei-Lin Chang wrote:
> > > Hi,
> > >
> > > This is v3 of optimizing the shadow s2 mmu unmapping during MMU
> > > notifiers.
> > >
> > > Two new preparatory patches are added, one reduces a hole in kvm_s2_mmu
> > > and another refactors the code a bit during s2 faults. Other changes are
> > > listed below.
> > >
> > > * Changes from v2 [1]:
> > >
> > > - Removed "polluted" teminology.
> > >
> > > - Use xa_{mk, to}_value() when storing and retriving values from maple
> > > trees.
> > >
> > > - Avoid using the 63rd bit in maple tree values so that xa_{mk, to}_value()
> > > does not lose us a bit.
> > >
> > > - Added reverse map removal during TLBI handling.
> > >
> > > - Other suggested refactorings.
> > >
> > > Thanks!
> >
> > With this series applied on the recent kvmarm/fixes (minor local modification),
> > your v3 hello_nested runs fine on all three page granules; without this 16KB
> > kernel can't handle stage 2 unmapping paths. I tested using the latest QEMU only
> > so wonder how you're testing.
>
> Can you clarify this statement?
>
> Are you saying that 16kB S2 unmap do not work with upstream? That
> seems odd, as it would mean NV wouldn't work on Apple HW, which
> represents two thirds of my development boxes...
Yes, I built this morning's upstream kvmarm/fixes with 16KB granule fresh, and tested
Wei Lin's propsed KVM selftest, hello_nested on QEMU with the small buildroot
filesystem and saw the above i.e., the stage 2 unmapping paths never finish.
I thought it was due to the Ubuntu userspace I was using for testing,
but not sure now.
Thanks,
Itaru.
>
> Thanks,
>
> M.
>
> --
> Without deviation from the norm, progress is not possible.
prev parent reply other threads:[~2026-05-29 0:55 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-10 14:53 [PATCH v3 0/5] KVM: arm64: nv: Implement nested stage-2 reverse map Wei-Lin Chang
2026-05-10 14:53 ` [PATCH v3 1/5] KVM: arm64: Use a variable for the canonical GPA in kvm_s2_fault_map() Wei-Lin Chang
2026-05-10 14:53 ` [PATCH v3 2/5] KVM: arm64: Move shadow_pt_debugfs_dentry to reduce holes in kvm_s2_mmu Wei-Lin Chang
2026-05-10 14:53 ` [PATCH v3 3/5] KVM: arm64: nv: Avoid full shadow s2 unmap Wei-Lin Chang
2026-05-28 12:59 ` Marc Zyngier
2026-05-10 14:53 ` [PATCH v3 4/5] KVM: arm64: nv: Remove reverse map entries during TLBI handling Wei-Lin Chang
2026-05-10 14:53 ` [PATCH v3 5/5] KVM: arm64: nv: Create nested IPA direct map to speed up reverse map removal Wei-Lin Chang
2026-06-04 7:24 ` Itaru Kitayama
2026-05-20 7:31 ` [PATCH v3 0/5] KVM: arm64: nv: Implement nested stage-2 reverse map Itaru Kitayama
2026-05-28 10:19 ` Marc Zyngier
2026-05-29 0:55 ` Itaru Kitayama [this message]
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