From: Oliver Upton <oupton@kernel.org>
To: Colton Lewis <coltonlewis@google.com>
Cc: stable@vger.kernel.org, Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
Oliver Upton <oliver.upton@linux.dev>,
James Morse <james.morse@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Zenghui Yu <yuzenghui@huawei.com>,
Mingwei Zhang <mizhang@google.com>,
linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/5] Backport ARM64 VHE boot fixes to 6.6.y
Date: Wed, 1 Jul 2026 16:23:21 -0700 [thread overview]
Message-ID: <akWhad3U5VNjWzxu@kernel.org> (raw)
In-Reply-To: <20260701204342.2654385-1-coltonlewis@google.com>
The subject prefix should be "[PATCH 6.6 0/5]" so people know right up
front where this is going.
On Wed, Jul 01, 2026 at 08:43:37PM +0000, Colton Lewis wrote:
> This series backports VHE CPU boot fixes to the 6.6.y stable branch.
>
> These fixes are already present in the 6.12.y stable branch (and
> newer), but are missing in 6.6.y. They are required to enable booting
> L1 guests with nested virtualization enabled (kvm-arm.mode=nested).
It's a bit worse than this. The architecture retroactively made
FEAT_E2H0 an optional feature, there are now implementations in the wild
that do not support the feature.
> Without these patches, a 6.6.y guest boots with HCR_EL2.E2H
> incorrectly configured (because it misses VHE-only detection or early
> initialization), causing early boot hangs/trap loops.
>
> Conflict resolutions:
> - Patch 4 (KVM: arm64: Initialize HCR_EL2.E2H early) had conflicts in
> arch/arm64/kvm/hyp/nvhe/hyp-init.S due to differences in state
> initialization. Resolved by extracting EL2 state initialization into
> __kvm_init_el2_state.
> - Patch 5 (arm64: Revamp HCR_EL2.E2H RES1 detection) had conflicts in
> arch/arm64/include/asm/el2_setup.h. Resolved by using raw msr hcr_el2
> instead of the missing msr_hcr_el2 macro.
>
>
> Marc Zyngier (4):
> arm64: sysreg: Add layout for ID_AA64MMFR4_EL1
> arm64: Treat HCR_EL2.E2H as RES1 when ID_AA64MMFR4_EL1.E2H0 is
> negative
> arm64: Fix early handling of FEAT_E2H0 not being implemented
> arm64: Revamp HCR_EL2.E2H RES1 detection
>
> Mark Rutland (1):
> KVM: arm64: Initialize HCR_EL2.E2H early
>
> arch/arm64/include/asm/el2_setup.h | 52 ++++++++++++++++++++++++++++++
> arch/arm64/kernel/head.S | 17 +++-------
> arch/arm64/kvm/hyp/nvhe/hyp-init.S | 16 +++++++--
> arch/arm64/tools/sysreg | 37 +++++++++++++++++++++
> 4 files changed, 107 insertions(+), 15 deletions(-)
>
>
> base-commit: d1cfde2d5d15be14123bdd1689162bd27f995a90
> --
> 2.55.0.rc2.803.g1fd1e6609c-goog
>
next prev parent reply other threads:[~2026-07-01 23:23 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-01 20:43 [PATCH 0/5] Backport ARM64 VHE boot fixes to 6.6.y Colton Lewis
2026-07-01 20:43 ` [PATCH 1/5] arm64: sysreg: Add layout for ID_AA64MMFR4_EL1 Colton Lewis
2026-07-01 20:43 ` [PATCH 2/5] arm64: Treat HCR_EL2.E2H as RES1 when ID_AA64MMFR4_EL1.E2H0 is negative Colton Lewis
2026-07-01 23:30 ` Oliver Upton
2026-07-01 20:43 ` [PATCH 3/5] arm64: Fix early handling of FEAT_E2H0 not being implemented Colton Lewis
2026-07-01 20:43 ` [PATCH 4/5] KVM: arm64: Initialize HCR_EL2.E2H early Colton Lewis
2026-07-01 23:45 ` Oliver Upton
2026-07-01 20:43 ` [PATCH 5/5] arm64: Revamp HCR_EL2.E2H RES1 detection Colton Lewis
2026-07-01 23:23 ` Oliver Upton [this message]
2026-07-02 0:01 ` [PATCH 0/5] Backport ARM64 VHE boot fixes to 6.6.y Oliver Upton
2026-07-02 0:38 ` Sasha Levin
2026-07-02 6:16 ` Greg KH
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