On Wed, Apr 25, 2018 at 07:54:41PM +0800, wei.guo.simon@xxxxxxxxx wrote:
> From: Simon Guo <wei.guo.simon@xxxxxxxxx>
>
> Currently HV will save math regs(FP/VEC/VSX) when trap into host. But
> PR KVM will only save math regs when qemu task switch out of CPU.
>
> To emulate FP/VEC/VSX load, PR KVM need to flush math regs firstly and
> then be able to update saved VCPU FPR/VEC/VSX area reasonably.
>
> This patch adds the giveup_ext() to KVM ops (an empty one for HV KVM)
> and kvmppc_complete_mmio_load() can invoke that hook to flush math
> regs accordingly.
>
> Math regs flush is also necessary for STORE, which will be covered
> in later patch within this patch series.
>
> Signed-off-by: Simon Guo <wei.guo.simon@xxxxxxxxx>
I don't see where you have provided a function for Book E.
I would suggest you only set the function pointer to non-NULL when the
function is actually needed, i.e. for PR KVM.
It seems to me that this means that emulation of FP/VMX/VSX loads is
currently broken for PR KVM for the case where kvm_io_bus_read() is
able to supply the data, and the emulation of FP/VMX/VSX stores is
broken for PR KVM for all cases. Do you agree?
> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
> index 5b875ba..7eb5507 100644
> --- a/arch/powerpc/kvm/book3s_hv.c
> +++ b/arch/powerpc/kvm/book3s_hv.c
> @@ -2084,6 +2084,10 @@ static int kvmhv_set_smt_mode(struct kvm *kvm, unsigned long smt_mode,
> return err;
> }
>
> +static void kvmhv_giveup_ext(struct kvm_vcpu *vcpu, ulong msr)
> +{
> +}
> +
> static void unpin_vpa(struct kvm *kvm, struct kvmppc_vpa *vpa)
> {
> if (vpa->pinned_addr)
> @@ -4398,6 +4402,7 @@ static int kvmhv_configure_mmu(struct kvm *kvm, struct kvm_ppc_mmuv3_cfg *cfg)
> .configure_mmu = kvmhv_configure_mmu,
> .get_rmmu_info = kvmhv_get_rmmu_info,
> .set_smt_mode = kvmhv_set_smt_mode,
> + .giveup_ext = kvmhv_giveup_ext,
> };
>
> static int kvm_init_subcore_bitmap(void)
I think HV KVM could leave this pointer as NULL, and then...
> diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
> index 17f0315..e724601 100644
> --- a/arch/powerpc/kvm/powerpc.c
> +++ b/arch/powerpc/kvm/powerpc.c
> @@ -1061,6 +1061,9 @@ static void kvmppc_complete_mmio_load(struct kvm_vcpu *vcpu,
> kvmppc_set_gpr(vcpu, vcpu->arch.io_gpr, gpr);
> break;
> case KVM_MMIO_REG_FPR:
> + if (!is_kvmppc_hv_enabled(vcpu->kvm))
> + vcpu->kvm->arch.kvm_ops->giveup_ext(vcpu, MSR_FP);
> +
This could become
if (vcpu->kvm->arch.kvm_ops->giveup_ext)
vcpu->kvm->arch.kvm_ops->giveup_ext(vcpu, MSR_FP);
and you wouldn't need to fix Book E explicitly.
Paul.
