From: Marc Zyngier <maz@kernel.org>
To: Will Deacon <will@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, kernel-team@android.com
Subject: Re: [PATCH 05/10] KVM: arm64: Rework SVE host-save/guest-restore
Date: Wed, 17 Mar 2021 14:54:51 +0000 [thread overview]
Message-ID: <878s6lj0ec.wl-maz@kernel.org> (raw)
In-Reply-To: <20210317142938.GA5393@willie-the-truck>
On Wed, 17 Mar 2021 14:29:39 +0000,
Will Deacon <will@kernel.org> wrote:
>
> On Tue, Mar 16, 2021 at 10:13:07AM +0000, Marc Zyngier wrote:
> > In order to keep the code readable, move the host-save/guest-restore
> > sequences in their own functions, with the following changes:
> > - the hypervisor ZCR is now set from C code
> > - ZCR_EL2 is always used as the EL2 accessor
> >
> > This results in some minor assembler macro rework.
> > No functional change intended.
> >
> > Signed-off-by: Marc Zyngier <maz@kernel.org>
> > ---
> > arch/arm64/include/asm/fpsimdmacros.h | 8 +++--
> > arch/arm64/include/asm/kvm_hyp.h | 2 +-
> > arch/arm64/kvm/hyp/fpsimd.S | 2 +-
> > arch/arm64/kvm/hyp/include/hyp/switch.h | 41 +++++++++++++++----------
> > 4 files changed, 33 insertions(+), 20 deletions(-)
>
> [...]
>
> > diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h
> > index fb68271c1a0f..d34dc220a1ce 100644
> > --- a/arch/arm64/kvm/hyp/include/hyp/switch.h
> > +++ b/arch/arm64/kvm/hyp/include/hyp/switch.h
> > @@ -196,6 +196,25 @@ static inline bool __populate_fault_info(struct kvm_vcpu *vcpu)
> > return true;
> > }
> >
> > +static inline void __hyp_sve_save_host(struct kvm_vcpu *vcpu)
> > +{
> > + struct thread_struct *thread;
> > +
> > + thread = container_of(vcpu->arch.host_fpsimd_state, struct thread_struct,
> > + uw.fpsimd_state);
> > +
> > + __sve_save_state(sve_pffr(thread), &vcpu->arch.host_fpsimd_state->fpsr);
> > +}
> > +
> > +static inline void __hyp_sve_restore_guest(struct kvm_vcpu *vcpu)
> > +{
> > + if (read_sysreg_s(SYS_ZCR_EL2) != (vcpu_sve_vq(vcpu) - 1))
>
> Strictly speaking, we should probably be extracting the LEN field from
> ZCR_EL2, otherwise this has the potential to go horribly wrong if any of
> the RES0 bits are allocated in future.
Good point, the equivalent asm macro has a BIC to that effect. I'll
fix that in the next round, as there are similar patterns in a number
of places.
> Other than that:
>
> Acked-by: Will Deacon <will@kernel.org>
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
next prev parent reply other threads:[~2021-03-17 16:04 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-16 10:13 [PATCH 00/10] KVM: arm64: Enable SVE support on nVHE systems Marc Zyngier
2021-03-16 10:13 ` [PATCH 01/10] KVM: arm64: Provide KVM's own save/restore SVE primitives Marc Zyngier
2021-03-16 10:31 ` Quentin Perret
2021-03-16 12:17 ` Marc Zyngier
2021-03-17 14:30 ` Will Deacon
2021-03-16 10:13 ` [PATCH 02/10] KVM: arm64: Use {read,write}_sysreg_el1 to access ZCR_EL1 Marc Zyngier
2021-03-17 14:31 ` Will Deacon
2021-03-16 10:13 ` [PATCH 03/10] KVM: arm64: Let vcpu_sve_pffr() handle HYP VAs Marc Zyngier
2021-03-17 14:31 ` Will Deacon
2021-03-16 10:13 ` [PATCH 04/10] KVM: arm64: Introduce vcpu_sve_vq() helper Marc Zyngier
2021-03-17 14:01 ` Will Deacon
2021-03-16 10:13 ` [PATCH 05/10] KVM: arm64: Rework SVE host-save/guest-restore Marc Zyngier
2021-03-17 14:29 ` Will Deacon
2021-03-17 14:54 ` Marc Zyngier [this message]
2021-03-16 10:13 ` [PATCH 06/10] KVM: arm64: Map SVE context at EL2 when available Marc Zyngier
2021-03-17 16:01 ` Will Deacon
2021-03-18 8:56 ` Marc Zyngier
2021-03-16 10:13 ` [PATCH 07/10] KVM: arm64: Save guest's ZCR_EL1 before saving the FPSIMD state Marc Zyngier
2021-03-17 17:17 ` Will Deacon
2021-03-17 17:20 ` Will Deacon
2021-03-16 10:13 ` [PATCH 08/10] KVM: arm64: Add a nVHE-specific SVE VQ reset hypercall Marc Zyngier
2021-03-16 10:45 ` Quentin Perret
2021-03-16 12:18 ` Marc Zyngier
2021-03-16 14:24 ` Andrew Scull
2021-03-16 15:00 ` Marc Zyngier
2021-03-16 10:13 ` [PATCH 09/10] KVM: arm64: Save/restore SVE state for nVHE Marc Zyngier
2021-03-17 17:57 ` Will Deacon
2021-03-18 9:12 ` Marc Zyngier
2021-03-16 10:13 ` [PATCH 10/10] KVM: arm64: Enable SVE support " Marc Zyngier
2021-03-17 18:00 ` Will Deacon
2021-03-18 9:14 ` Marc Zyngier
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