KVM: SEV: Add support for SEV-ES intra host migration

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: Tom Lendacky <thomas.lendacky@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
Message-Id: <20211021174303.385706-4-pgonda@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 8b52902..f63f915 100644 (file)
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -1612,6 +1612,46 @@ 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 = kvm_get_vcpu(dst, i);
+               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.
+                */
+               memcpy(&dst_svm->sev_es, &src_svm->sev_es, sizeof(src_svm->sev_es));
+               dst_svm->vmcb->control.ghcb_gpa = src_svm->vmcb->control.ghcb_gpa;
+               dst_svm->vmcb->control.vmsa_pa = src_svm->vmcb->control.vmsa_pa;
+               dst_vcpu->arch.guest_state_protected = true;
+
+               memset(&src_svm->sev_es, 0, sizeof(src_svm->sev_es));
+               src_svm->vmcb->control.ghcb_gpa = INVALID_PAGE;
+               src_svm->vmcb->control.vmsa_pa = INVALID_PAGE;
+               src_vcpu->arch.guest_state_protected = false;
+       }
+       to_kvm_svm(src)->sev_info.es_active = false;
+       to_kvm_svm(dst)->sev_info.es_active = true;
+
+       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;
@@ -1640,7 +1680,7 @@ 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;
        }
@@ -1660,10 +1700,16 @@ int svm_vm_migrate_from(struct kvm *kvm, unsigned int source_fd)
        if (ret)
                goto out_dst_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, src_sev);
        kvm_vm_dead(source_kvm);
        ret = 0;
 
+out_source_vcpu:
        sev_unlock_vcpus_for_migration(source_kvm);
 out_dst_vcpu:
        sev_unlock_vcpus_for_migration(kvm);