Re: [PATCH v8 18/18] KVM: SVM: Enable SEV live migration feature implicitly on Incoming VM(s).

Paolo Bonzini
2020-12-04T11:24:21Z

On 05/05/20 23:22, Ashish Kalra wrote:
> From: Ashish Kalra <ashish.kalra@amd.com>
>
> For source VM, live migration feature is enabled explicitly
> when the guest is booting, for the incoming VM(s) it is implied.
> This is required for handling A->B->C->... VM migrations case.
>
> Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
> ---
> arch/x86/kvm/svm/sev.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> index 6f69c3a47583..ba7c0ebfa1f3 100644
> --- a/arch/x86/kvm/svm/sev.c
> +++ b/arch/x86/kvm/svm/sev.c
> @@ -1592,6 +1592,13 @@ int svm_set_page_enc_bitmap(struct kvm *kvm,
> if (ret)
> goto unlock;
>
> + /*
> + * For source VM, live migration feature is enabled
> + * explicitly when the guest is booting, for the
> + * incoming VM(s) it is implied.
> + */
> + sev_update_migration_flags(kvm, KVM_SEV_LIVE_MIGRATION_ENABLED);
> +
> bitmap_copy(sev->page_enc_bmap + BIT_WORD(gfn_start), bitmap,
> (gfn_end - gfn_start));
>
>

I would prefer that userspace does this using KVM_SET_MSR instead.

Paolo