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@xxxxxxxxxx>
Reviewed-by: Marc Orr <marcorr@xxxxxxxxxx>
Cc: Marc Orr <marcorr@xxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Sean Christopherson <seanjc@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Dr. David Alan Gilbert <dgilbert@xxxxxxxxxx>
Cc: Brijesh Singh <brijesh.singh@xxxxxxx>
Cc: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
Cc: Wanpeng Li <wanpengli@xxxxxxxxxxx>
Cc: Jim Mattson <jmattson@xxxxxxxxxx>
Cc: Joerg Roedel <joro@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: kvm@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
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);
