Vaibhav Jain <vaibhav@xxxxxxxxxxxxx> writes:
> From: Jordan Niethe <jniethe5@xxxxxxxxx>
>
> An L0 must invalidate the L2's RPT during H_GUEST_DELETE if this has not
> already been done. This is a slow operation that means H_GUEST_DELETE
> must return H_BUSY multiple times before completing. Invalidating the
> tables before deleting the guest so there is less work for the L0 to do.
>
> Signed-off-by: Jordan Niethe <jniethe5@xxxxxxxxx>
> ---
> arch/powerpc/include/asm/kvm_book3s.h | 1 +
> arch/powerpc/kvm/book3s_hv.c | 6 ++++--
> arch/powerpc/kvm/book3s_hv_nested.c | 2 +-
> 3 files changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
> index 4f527d09c92b..a37736ed3728 100644
> --- a/arch/powerpc/include/asm/kvm_book3s.h
> +++ b/arch/powerpc/include/asm/kvm_book3s.h
> @@ -302,6 +302,7 @@ void kvmhv_nested_exit(void);
> void kvmhv_vm_nested_init(struct kvm *kvm);
> long kvmhv_set_partition_table(struct kvm_vcpu *vcpu);
> long kvmhv_copy_tofrom_guest_nested(struct kvm_vcpu *vcpu);
> +void kvmhv_flush_lpid(u64 lpid);
> void kvmhv_set_ptbl_entry(u64 lpid, u64 dw0, u64 dw1);
> void kvmhv_release_all_nested(struct kvm *kvm);
> long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu);
> diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
> index 1ed6ec140701..5543e8490cd9 100644
> --- a/arch/powerpc/kvm/book3s_hv.c
> +++ b/arch/powerpc/kvm/book3s_hv.c
> @@ -5691,10 +5691,12 @@ static void kvmppc_core_destroy_vm_hv(struct kvm *kvm)
> kvmhv_set_ptbl_entry(kvm->arch.lpid, 0, 0);
> }
>
> - if (kvmhv_is_nestedv2())
> + if (kvmhv_is_nestedv2()) {
> + kvmhv_flush_lpid(kvm->arch.lpid);
> plpar_guest_delete(0, kvm->arch.lpid);
>
I am not sure I follow the optimization here. I would expect the
hypervisor to kill all the translation caches as part of guest_delete.
What is the benefit of doing a lpid flush outside the guest delete?
> - else
> + } else {
> kvmppc_free_lpid(kvm->arch.lpid);
> + }
>
> kvmppc_free_pimap(kvm);
> }
> diff --git a/arch/powerpc/kvm/book3s_hv_nested.c b/arch/powerpc/kvm/book3s_hv_nested.c
> index 3b658b8696bc..5c375ec1a3c6 100644
> --- a/arch/powerpc/kvm/book3s_hv_nested.c
> +++ b/arch/powerpc/kvm/book3s_hv_nested.c
> @@ -503,7 +503,7 @@ void kvmhv_nested_exit(void)
> }
> }
>
> -static void kvmhv_flush_lpid(u64 lpid)
> +void kvmhv_flush_lpid(u64 lpid)
> {
> long rc;
>
> --
> 2.42.0
