On Wed, 13 Oct 2021 16:58:18 +0100,
Quentin Perret <qperret@xxxxxxxxxx> wrote:
>
> We currently map the SVE state into the hypervisor stage-1 on VCPU_RUN,
> when the vCPU thread's PID has changed. However, this only needs to be
> done during the first VCPU_RUN as the SVE state doesn't depend on
> thread-specific data, so move the create_hyp_mapping() call to
> kvm_vcpu_first_run_init().
>
> Suggested-by: Marc Zyngier <maz@xxxxxxxxxx>
> Signed-off-by: Quentin Perret <qperret@xxxxxxxxxx>
> ---
> arch/arm64/kvm/arm.c | 12 ++++++++++++
> arch/arm64/kvm/fpsimd.c | 11 -----------
> 2 files changed, 12 insertions(+), 11 deletions(-)
>
> diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
> index fe102cd2e518..c33d8c073820 100644
> --- a/arch/arm64/kvm/arm.c
> +++ b/arch/arm64/kvm/arm.c
> @@ -618,6 +618,18 @@ static int kvm_vcpu_first_run_init(struct kvm_vcpu *vcpu)
> if (ret)
> return ret;
>
> + if (vcpu->arch.sve_state) {
> + void *sve_end;
> +
> + sve_end = vcpu->arch.sve_state + vcpu_sve_state_size(vcpu);
> +
> + ret = create_hyp_mappings(vcpu->arch.sve_state, sve_end,
> + PAGE_HYP);
> + if (ret)
> + return ret;
> + }
> +
> +
> ret = kvm_arm_pmu_v3_enable(vcpu);
>
> return ret;
> diff --git a/arch/arm64/kvm/fpsimd.c b/arch/arm64/kvm/fpsimd.c
> index 5621020b28de..62c0d78da7be 100644
> --- a/arch/arm64/kvm/fpsimd.c
> +++ b/arch/arm64/kvm/fpsimd.c
> @@ -43,17 +43,6 @@ int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu)
> if (ret)
> goto error;
>
> - if (vcpu->arch.sve_state) {
> - void *sve_end;
> -
> - sve_end = vcpu->arch.sve_state + vcpu_sve_state_size(vcpu);
> -
> - ret = create_hyp_mappings(vcpu->arch.sve_state, sve_end,
> - PAGE_HYP);
> - if (ret)
> - goto error;
> - }
> -
> vcpu->arch.host_thread_info = kern_hyp_va(ti);
> vcpu->arch.host_fpsimd_state = kern_hyp_va(fpsimd);
> error:
I actually ended-up implementing a similar patch as part of my 'first
run' series[1], though I moved the mapping to the point where we
finalise the vcpu as that's where the allocation takes place.
Do you see any potential issue with that approach?
Thanks,
M.
[1] https://lore.kernel.org/r/20211015090822.2994920-2-maz@xxxxxxxxxx
--
Without deviation from the norm, progress is not possible.
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