linux-kernel - [PATCH 0/4] KVM: arm64: Fix CPU resume/on with pKVM

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Message-ID: <20230201103755.1398086-1-qperret@google.com>
Date:   Wed,  1 Feb 2023 10:37:50 +0000
From:   Quentin Perret <qperret@...gle.com>
To:     Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>, Marc Zyngier <maz@...nel.org>,
        James Morse <james.morse@....com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Oliver Upton <oliver.upton@...ux.dev>,
        Zenghui Yu <yuzenghui@...wei.com>,
        Mark Brown <broonie@...nel.org>
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        kvmarm@...ts.linux.dev, kvmarm@...ts.cs.columbia.edu,
        kernel-team@...roid.com, Quentin Perret <qperret@...gle.com>
Subject: [PATCH 0/4] KVM: arm64: Fix CPU resume/on with pKVM

When using pKVM, we do not reset the EL2 exception vectors back to the
stubs for e.g. Power Management or CPU hotplug as we normally do in KVM.
As consequence, the initialisation perfomed by __finalise_el2 is missing
on e.g. the CPU_RESUME path with pKVM, hence leaving certain registers
in an incorrect state.

One such example is ZCR_EL2 which remains configured with SVE traps
enabled. And so using SVE on a CPU that has gone through a hotplug
off/on cycle leads to a hyp panic. Not good.

This series fixes this by macroizing the first half of __finalise_el2
(that is, the part that is not specific to VHE) to allow its re-use
from pKVM's PSCI relay.

Quentin Perret (4):
  KVM: arm64: Provide sanitized SYS_ID_AA64SMFR0_EL1 to nVHE
  KVM: arm64: Introduce finalise_el2_state macro
  KVM: arm64: Use sanitized values in __check_override in nVHE
  KVM: arm64: Finalise EL2 state from pKVM PSCI relay

 arch/arm64/include/asm/el2_setup.h | 92 ++++++++++++++++++++++++++++++
 arch/arm64/include/asm/kvm_hyp.h   |  1 +
 arch/arm64/kernel/hyp-stub.S       | 79 +------------------------
 arch/arm64/kvm/arm.c               |  1 +
 arch/arm64/kvm/hyp/nvhe/hyp-init.S |  1 +
 arch/arm64/kvm/hyp/nvhe/sys_regs.c |  1 +
 6 files changed, 98 insertions(+), 77 deletions(-)

-- 
2.39.1.456.gfc5497dd1b-goog