Messages in this thread | | | Subject | Re: [PATCH 2/4 V9] KVM: SEV: Add support for SEV-ES intra host migration | From | Tom Lendacky <> | Date | Fri, 8 Oct 2021 10:38:09 -0500 |
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On 10/5/21 9:13 AM, Peter Gonda wrote: > For SEV-ES to work with intra host migration the VMSAs, GHCB metadata, > and other SEV-ES info needs to be preserved along with the guest's > memory. > > Signed-off-by: Peter Gonda <pgonda@google.com> > Reviewed-by: Marc Orr <marcorr@google.com> > Cc: Marc Orr <marcorr@google.com> > Cc: Paolo Bonzini <pbonzini@redhat.com> > Cc: Sean Christopherson <seanjc@google.com> > Cc: David Rientjes <rientjes@google.com> > Cc: Dr. David Alan Gilbert <dgilbert@redhat.com> > Cc: Brijesh Singh <brijesh.singh@amd.com> > Cc: Vitaly Kuznetsov <vkuznets@redhat.com> > Cc: Wanpeng Li <wanpengli@tencent.com> > Cc: Jim Mattson <jmattson@google.com> > Cc: Joerg Roedel <joro@8bytes.org> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Ingo Molnar <mingo@redhat.com> > Cc: Borislav Petkov <bp@alien8.de> > Cc: "H. Peter Anvin" <hpa@zytor.com> > Cc: kvm@vger.kernel.org > Cc: linux-kernel@vger.kernel.org > --- > arch/x86/kvm/svm/sev.c | 53 +++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 52 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c > index 6fc1935b52ea..321b55654f36 100644 > --- a/arch/x86/kvm/svm/sev.c > +++ b/arch/x86/kvm/svm/sev.c > @@ -1576,6 +1576,51 @@ static void sev_migrate_from(struct kvm_sev_info *dst, > list_replace_init(&src->regions_list, &dst->regions_list); > } > > +static int sev_es_migrate_from(struct kvm *dst, struct kvm *src) > +{ > + int i; > + struct kvm_vcpu *dst_vcpu, *src_vcpu; > + struct vcpu_svm *dst_svm, *src_svm; > + > + if (atomic_read(&src->online_vcpus) != atomic_read(&dst->online_vcpus)) > + return -EINVAL; > + > + kvm_for_each_vcpu(i, src_vcpu, src) { > + if (!src_vcpu->arch.guest_state_protected) > + return -EINVAL; > + } > + > + kvm_for_each_vcpu(i, src_vcpu, src) { > + src_svm = to_svm(src_vcpu); > + dst_vcpu = dst->vcpus[i]; > + dst_vcpu = kvm_get_vcpu(dst, i);
One of these assignments of dst_vcpu can be deleted.
> + dst_svm = to_svm(dst_vcpu); > + > + /* > + * Transfer VMSA and GHCB state to the destination. Nullify and > + * clear source fields as appropriate, the state now belongs to > + * the destination. > + */ > + dst_vcpu->vcpu_id = src_vcpu->vcpu_id; > + dst_svm->vmsa = src_svm->vmsa; > + src_svm->vmsa = NULL; > + dst_svm->ghcb = src_svm->ghcb; > + src_svm->ghcb = NULL; > + dst_svm->vmcb->control.ghcb_gpa = src_svm->vmcb->control.ghcb_gpa; > + dst_svm->ghcb_sa = src_svm->ghcb_sa; > + src_svm->ghcb_sa = NULL; > + dst_svm->ghcb_sa_len = src_svm->ghcb_sa_len; > + src_svm->ghcb_sa_len = 0; > + dst_svm->ghcb_sa_sync = src_svm->ghcb_sa_sync; > + src_svm->ghcb_sa_sync = false; > + dst_svm->ghcb_sa_free = src_svm->ghcb_sa_free; > + src_svm->ghcb_sa_free = false;
Would it make sense to have a pre-patch that puts these fields into a struct? Then you can just copy the struct and zero it after. If anything is ever added for any reason, then it could/should be added to the struct and this code wouldn't have to change. It might be more churn than it's worth, just a thought.
Thanks, Tom
> + } > + to_kvm_svm(src)->sev_info.es_active = false; > + > + return 0; > +} > + > int svm_vm_migrate_from(struct kvm *kvm, unsigned int source_fd) > { > struct kvm_sev_info *dst_sev = &to_kvm_svm(kvm)->sev_info; > @@ -1604,7 +1649,7 @@ int svm_vm_migrate_from(struct kvm *kvm, unsigned int source_fd) > if (ret) > goto out_fput; > > - if (!sev_guest(source_kvm) || sev_es_guest(source_kvm)) { > + if (!sev_guest(source_kvm)) { > ret = -EINVAL; > goto out_source; > } > @@ -1615,6 +1660,12 @@ int svm_vm_migrate_from(struct kvm *kvm, unsigned int source_fd) > if (ret) > goto out_source_vcpu; > > + if (sev_es_guest(source_kvm)) { > + ret = sev_es_migrate_from(kvm, source_kvm); > + if (ret) > + goto out_source_vcpu; > + } > + > sev_migrate_from(dst_sev, &to_kvm_svm(source_kvm)->sev_info); > kvm_for_each_vcpu (i, vcpu, source_kvm) { > kvm_vcpu_reset(vcpu, /* init_event= */ false); >
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