From: Marc Zyngier <maz@kernel.org>
To: Dong Bo <dongbo4@huawei.com>
Cc: <linux-kernel@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>, <kvmarm@lists.linux.dev>,
<kvmarm@lists.cs.columbia.edu>,
Nianyao Tang <tangnianyao@huawei.com>,
James Morse <james.morse@arm.com>,
Alexandru Elisei <alexandru.elisei@arm.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
Oliver Upton <oliver.upton@linux.dev>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>, Mark Brown <broonie@kernel.org>
Subject: Re: [PATCH] KVM: arm64: Synchronize SMEN on vcpu schedule out
Date: Tue, 20 Dec 2022 10:15:18 +0000 [thread overview]
Message-ID: <86v8m6bcuh.wl-maz@kernel.org> (raw)
In-Reply-To: <20221220105024.13484-1-dongbo4@huawei.com>
+ Mark
On Tue, 20 Dec 2022 10:50:24 +0000,
Dong Bo <dongbo4@huawei.com> wrote:
>
> From: Nianyao Tang <tangnianyao@huawei.com>
>
> If we have VHE and need to reenable SME for host in
> kvm_arch_vcpu_put_fp, CPACR.SMEN is modified from 0 to 1. Trap
> control for reading SVCR is modified from enable to disable.
> Synchronization is needed before reading SVCR later in
> fpsimd_save, or it may cause sync exception which can not be
> handled by host.
>
> Cc: Marc Zyngier <maz@kernel.org>
> Cc: James Morse <james.morse@arm.com>
> Cc: Alexandru Elisei <alexandru.elisei@arm.com>
> Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
> Cc: Oliver Upton <oliver.upton@linux.dev>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will@kernel.org>
> Signed-off-by: Nianyao Tang <tangnianyao@huawei.com>
> ---
> arch/arm64/kvm/fpsimd.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c
> index 02dd7e9ebd39..f5799f571317 100644
> --- a/arch/arm64/kvm/fpsimd.c
> +++ b/arch/arm64/kvm/fpsimd.c
> @@ -184,6 +184,7 @@ void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu)
> sysreg_clear_set(CPACR_EL1,
> CPACR_EL1_SMEN_EL0EN,
> CPACR_EL1_SMEN_EL1EN);
> + isb();
> }
>
> if (vcpu->arch.fp_state == FP_STATE_GUEST_OWNED) {
> --
> 1.8.3.1
>
>
--
Without deviation from the norm, progress is not possible.
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next prev parent reply other threads:[~2022-12-20 10:25 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-20 10:50 [PATCH] KVM: arm64: Synchronize SMEN on vcpu schedule out Dong Bo
2022-12-20 10:15 ` Marc Zyngier [this message]
2022-12-21 13:34 ` Mark Brown
2023-01-23 20:26 ` Oliver Upton
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