From: Joey Gouly <joey.gouly@arm•com>
To: Marc Zyngier <maz@kernel•org>
Cc: kvmarm@lists•linux.dev, linux-arm-kernel@lists•infradead.org,
kvm@vger•kernel.org, Steffen Eiden <seiden@linux•ibm.com>,
Suzuki K Poulose <suzuki.poulose@arm•com>,
Oliver Upton <oupton@kernel•org>,
Zenghui Yu <yuzenghui@huawei•com>
Subject: Re: [PATCH 0/3] KVM: arm64: FEAT_{S1POE,ATS1A} support fixes
Date: Wed, 3 Jun 2026 11:41:42 +0100 [thread overview]
Message-ID: <20260603104142.GA2078466@e124191.cambridge.arm.com> (raw)
In-Reply-To: <20260602155430.2088142-1-maz@kernel.org>
On Tue, Jun 02, 2026 at 04:54:26PM +0100, Marc Zyngier wrote:
> Whilst working on a slightly unrelated feature (FEAT_NV3), I found out
> that an L2 guest wouldn't boot if the host was exposed to FEAT_S1POE.
>
> Upon investigation (and hours wasted in a SW model), it became
> apparent that while the AT S1E1A code was ready for action, it had
> never been fully plugged in (blame the usual suspect...).
>
> This resulted in an extremely odd failure mode, with an L2 being
> unable to make forward progress, but KVM at L1 not taking the hint
> that something was really wrong. Additionally, an embarrassing typo
> was spotted in the CPTR_EL2 handling.
>
> With this in, FEAT_S1POE no longer breaks our NV guests.
>
> Marc Zyngier (3):
> KVM: arm64: Key CPTR_EL2.E0POE propagation on FEAT_S1POE
> KVM: arm64: Wire AT S1E1A in the system instruction handling table
> arm64: cpufeature: Expose ID_AA64ISAR2_EL1.ATS1A to KVM
>
> arch/arm64/kernel/cpufeature.c | 1 +
> arch/arm64/kvm/hyp/include/hyp/switch.h | 2 +-
> arch/arm64/kvm/sys_regs.c | 1 +
> 3 files changed, 3 insertions(+), 1 deletion(-)
Reviewed-by: Joey Gouly <joey.gouly@arm•com>
Thanks,
Joey
prev parent reply other threads:[~2026-06-03 10:41 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-02 15:54 [PATCH 0/3] KVM: arm64: FEAT_{S1POE,ATS1A} support fixes Marc Zyngier
2026-06-02 15:54 ` [PATCH 1/3] KVM: arm64: Key CPTR_EL2.E0POE propagation on FEAT_S1POE Marc Zyngier
2026-06-02 15:54 ` [PATCH 2/3] KVM: arm64: Wire AT S1E1A in the system instruction handling table Marc Zyngier
2026-06-02 15:54 ` [PATCH 3/3] arm64: cpufeature: Expose ID_AA64ISAR2_EL1.ATS1A to KVM Marc Zyngier
2026-06-02 17:49 ` [PATCH 0/3] KVM: arm64: FEAT_{S1POE,ATS1A} support fixes Oliver Upton
2026-06-03 10:41 ` Joey Gouly [this message]
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