From: Will Deacon <will@kernel.org>
To: Marc Zyngier <maz@kernel.org>
Cc: kvmarm@lists.cs.columbia.edu,
linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org,
dave.martin@arm.com, daniel.kiss@arm.com,
Catalin Marinas <catalin.marinas@arm.com>,
James Morse <james.morse@arm.com>,
Julien Thierry <julien.thierry.kdev@gmail.com>,
Suzuki K Poulose <suzuki.poulose@arm.com>,
broonie@kernel.org, ascull@google.com, qperret@google.com,
kernel-team@android.com
Subject: Re: [PATCH v2 10/11] KVM: arm64: Save/restore SVE state for nVHE
Date: Thu, 18 Mar 2021 14:13:58 +0000 [thread overview]
Message-ID: <20210318141358.GF7055@willie-the-truck> (raw)
In-Reply-To: <20210318122532.505263-11-maz@kernel.org>
On Thu, Mar 18, 2021 at 12:25:31PM +0000, Marc Zyngier wrote:
> Implement the SVE save/restore for nVHE, following a similar
> logic to that of the VHE implementation:
>
> - the SVE state is switched on trap from EL1 to EL2
>
> - no further changes to ZCR_EL2 occur as long as the guest isn't
> preempted or exit to userspace
>
> - ZCR_EL2 is reset to its default value on the first SVE access from
> the host EL1, and ZCR_EL1 restored to the default guest value in
> vcpu_put()
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
> arch/arm64/kvm/fpsimd.c | 10 +++++--
> arch/arm64/kvm/hyp/include/hyp/switch.h | 37 +++++++++----------------
> arch/arm64/kvm/hyp/nvhe/switch.c | 4 +--
> 3 files changed, 23 insertions(+), 28 deletions(-)
>
> diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c
> index 14ea05c5134a..5621020b28de 100644
> --- a/arch/arm64/kvm/fpsimd.c
> +++ b/arch/arm64/kvm/fpsimd.c
> @@ -121,11 +121,17 @@ void kvm_arch_vcpu_put_fp(struct kvm_vcpu *vcpu)
> local_irq_save(flags);
>
> if (vcpu->arch.flags & KVM_ARM64_FP_ENABLED) {
> - if (guest_has_sve)
> + if (guest_has_sve) {
> __vcpu_sys_reg(vcpu, ZCR_EL1) = read_sysreg_el1(SYS_ZCR);
>
> + /* Restore the VL that was saved when bound to the CPU */
> + if (!has_vhe())
> + sve_cond_update_zcr_vq(vcpu_sve_max_vq(vcpu) - 1,
> + SYS_ZCR_EL1);
You end up reading ZCR_EL1 twice here, but it's probably not the end of the
world.
Anyway:
Acked-by: Will Deacon <will@kernel.org>
Will
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next prev parent reply other threads:[~2021-03-18 14:15 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-18 12:25 [PATCH v2 00/11] KVM: arm64: Enable SVE support on nVHE systems Marc Zyngier
2021-03-18 12:25 ` [PATCH v2 01/11] KVM: arm64: Provide KVM's own save/restore SVE primitives Marc Zyngier
2021-03-18 12:25 ` [PATCH v2 02/11] KVM: arm64: Use {read, write}_sysreg_el1 to access ZCR_EL1 Marc Zyngier
2021-03-18 12:25 ` [PATCH v2 03/11] KVM: arm64: Let vcpu_sve_pffr() handle HYP VAs Marc Zyngier
2021-03-18 12:25 ` [PATCH v2 04/11] KVM: arm64: Introduce vcpu_sve_vq() helper Marc Zyngier
2021-03-18 12:25 ` [PATCH v2 05/11] arm64: sve: Provide a conditional update accessor for ZCR_ELx Marc Zyngier
2021-03-18 13:32 ` Will Deacon
2021-03-19 16:42 ` Mark Brown
2021-03-19 16:51 ` Marc Zyngier
2021-03-19 16:58 ` Mark Brown
2021-03-18 12:25 ` [PATCH v2 06/11] KVM: arm64: Rework SVE host-save/guest-restore Marc Zyngier
2021-03-18 13:34 ` Will Deacon
2021-03-18 12:25 ` [PATCH v2 07/11] KVM: arm64: Map SVE context at EL2 when available Marc Zyngier
2021-03-18 13:35 ` Will Deacon
2021-03-18 12:25 ` [PATCH v2 08/11] KVM: arm64: Save guest's ZCR_EL1 before saving the FPSIMD state Marc Zyngier
2021-03-18 12:25 ` [PATCH v2 09/11] KVM: arm64: Trap host SVE accesses when the FPSIMD state is dirty Marc Zyngier
2021-03-18 14:11 ` Will Deacon
2021-03-18 14:29 ` Marc Zyngier
2021-03-18 18:40 ` Marc Zyngier
2021-03-18 12:25 ` [PATCH v2 10/11] KVM: arm64: Save/restore SVE state for nVHE Marc Zyngier
2021-03-18 14:13 ` Will Deacon [this message]
2021-03-18 14:32 ` Marc Zyngier
2021-03-18 12:25 ` [PATCH v2 11/11] KVM: arm64: Enable SVE support " Marc Zyngier
2021-03-19 17:53 ` [PATCH v2 00/11] KVM: arm64: Enable SVE support on nVHE systems Mark Brown
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