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Message-Id: <20210726195015.2106033-4-pgonda@google.com>
Date: Mon, 26 Jul 2021 12:50:15 -0700
From: Peter Gonda <pgonda@...gle.com>
To: kvm@...r.kernel.org
Cc: Peter Gonda <pgonda@...gle.com>,
Brijesh Singh <brijesh.singh@....com>,
Marc Orr <marcorr@...gle.com>,
Paolo Bonzini <pbonzini@...hat.com>,
Sean Christopherson <seanjc@...gle.com>,
David Rientjes <rientjes@...gle.com>,
"Dr . David Alan Gilbert" <dgilbert@...hat.com>,
Vitaly Kuznetsov <vkuznets@...hat.com>,
Wanpeng Li <wanpengli@...cent.com>,
Jim Mattson <jmattson@...gle.com>,
Joerg Roedel <joro@...tes.org>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
"H. Peter Anvin" <hpa@...or.com>, linux-kernel@...r.kernel.org
Subject: [PATCH 3/3 V3] 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@...gle.com>
Reviewed-by: Brijesh Singh <brijesh.singh@....com>
Reviewed-by: Marc Orr <marcorr@...gle.com>
Cc: Paolo Bonzini <pbonzini@...hat.com>
Cc: Sean Christopherson <seanjc@...gle.com>
Cc: David Rientjes <rientjes@...gle.com>
Cc: Dr. David Alan Gilbert <dgilbert@...hat.com>
Cc: Brijesh Singh <brijesh.singh@....com>
Cc: Vitaly Kuznetsov <vkuznets@...hat.com>
Cc: Wanpeng Li <wanpengli@...cent.com>
Cc: Jim Mattson <jmattson@...gle.com>
Cc: Joerg Roedel <joro@...tes.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Borislav Petkov <bp@...en8.de>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: kvm@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
---
arch/x86/kvm/svm/sev.c | 145 ++++++++++++++++++++++++++++++++++++++---
1 file changed, 135 insertions(+), 10 deletions(-)
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 082255b18840..4f8186b3507f 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -77,6 +77,19 @@ struct enc_region {
unsigned long size;
};
+struct vmsa_node {
+ struct list_head list;
+ int vcpu_id;
+ struct vmcb_save_area *vmsa;
+ struct ghcb *ghcb;
+ u64 ghcb_gpa;
+
+ void *ghcb_sa;
+ u64 ghcb_sa_len;
+ bool ghcb_sa_sync;
+ bool ghcb_sa_free;
+};
+
struct sev_info_migration_node {
struct hlist_node hnode;
u64 token;
@@ -87,6 +100,11 @@ struct sev_info_migration_node {
unsigned long pages_locked;
struct list_head regions_list;
struct misc_cg *misc_cg;
+
+ /* The following fields are for SEV-ES guests */
+ bool es_enabled;
+ struct list_head vmsa_list;
+ u64 ap_jump_table;
};
#define SEV_INFO_MIGRATION_HASH_BITS 7
@@ -1157,6 +1175,87 @@ static int place_migration_node(struct sev_info_migration_node *entry)
return ret;
}
+static void process_vmsa_list(struct kvm *kvm, struct list_head *vmsa_list)
+{
+ struct vmsa_node *vmsa_node, *q;
+ struct kvm_vcpu *vcpu;
+ struct vcpu_svm *svm;
+
+ lockdep_assert_held(&kvm->lock);
+
+ /*
+ * Move any stashed VMSAs back to their respective VMCBs and delete
+ * those nodes.
+ */
+ list_for_each_entry_safe(vmsa_node, q, vmsa_list, list) {
+ vcpu = kvm_get_vcpu_by_id(kvm, vmsa_node->vcpu_id);
+ if (WARN_ON(!vcpu))
+ continue;
+
+ svm = to_svm(vcpu);
+ svm->vmsa = vmsa_node->vmsa;
+ svm->ghcb = vmsa_node->ghcb;
+ svm->vmcb->control.ghcb_gpa = vmsa_node->ghcb_gpa;
+ svm->vcpu.arch.guest_state_protected = true;
+ svm->vmcb->control.vmsa_pa = __pa(svm->vmsa);
+ svm->ghcb_sa = vmsa_node->ghcb_sa;
+ svm->ghcb_sa_len = vmsa_node->ghcb_sa_len;
+ svm->ghcb_sa_sync = vmsa_node->ghcb_sa_sync;
+ svm->ghcb_sa_free = vmsa_node->ghcb_sa_free;
+
+ list_del(&vmsa_node->list);
+ kfree(vmsa_node);
+ }
+}
+
+static int create_vmsa_list(struct kvm *kvm,
+ struct sev_info_migration_node *entry)
+{
+ int i;
+ const int num_vcpus = atomic_read(&kvm->online_vcpus);
+ struct vmsa_node *node;
+ struct kvm_vcpu *vcpu;
+ struct vcpu_svm *svm;
+
+
+ INIT_LIST_HEAD(&entry->vmsa_list);
+ for (i = 0; i < num_vcpus; ++i) {
+ node = kzalloc(sizeof(*node), GFP_KERNEL);
+ if (!node)
+ goto e_freelist;
+
+ vcpu = kvm->vcpus[i];
+ if (!vcpu->arch.guest_state_protected) {
+ kfree(node);
+ goto e_freelist;
+ }
+
+ node->vcpu_id = vcpu->vcpu_id;
+ svm = to_svm(vcpu);
+ node->vmsa = svm->vmsa;
+ svm->vmsa = NULL;
+ node->ghcb = svm->ghcb;
+ svm->ghcb = NULL;
+ node->ghcb_gpa = svm->vmcb->control.ghcb_gpa;
+ node->ghcb_sa = svm->ghcb_sa;
+ svm->ghcb_sa = NULL;
+ node->ghcb_sa_len = svm->ghcb_sa_len;
+ svm->ghcb_sa_len = 0;
+ node->ghcb_sa_sync = svm->ghcb_sa_sync;
+ svm->ghcb_sa_sync = false;
+ node->ghcb_sa_free = svm->ghcb_sa_free;
+ svm->ghcb_sa_free = false;
+
+ list_add_tail(&node->list, &entry->vmsa_list);
+ }
+
+ return 0;
+
+e_freelist:
+ process_vmsa_list(kvm, &entry->vmsa_list);
+ return -1;
+}
+
static int sev_intra_host_send(struct kvm *kvm, struct kvm_sev_cmd *argp)
{
struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
@@ -1167,9 +1266,6 @@ static int sev_intra_host_send(struct kvm *kvm, struct kvm_sev_cmd *argp)
if (!sev_guest(kvm))
return -ENOTTY;
- if (sev->es_active)
- return -EPERM;
-
if (sev->handle == 0)
return -EPERM;
@@ -1196,13 +1292,28 @@ static int sev_intra_host_send(struct kvm *kvm, struct kvm_sev_cmd *argp)
INIT_LIST_HEAD(&entry->regions_list);
list_replace_init(&sev->regions_list, &entry->regions_list);
+ if (sev_es_guest(kvm)) {
+ /*
+ * If this is an ES guest, we need to move each VMCB's VMSA
+ * into a list for migration.
+ */
+ entry->es_enabled = true;
+ entry->ap_jump_table = sev->ap_jump_table;
+ if (create_vmsa_list(kvm, entry))
+ goto e_listdel;
+ }
+
if (place_migration_node(entry))
- goto e_listdel;
+ goto e_vmsadel;
sev->info_token = entry->token;
return 0;
+e_vmsadel:
+ if (sev_es_guest(kvm))
+ process_vmsa_list(kvm, &entry->vmsa_list);
+
e_listdel:
list_replace_init(&entry->regions_list, &sev->regions_list);
@@ -1223,9 +1334,6 @@ static int sev_intra_host_receive(struct kvm *kvm,
if (!sev_guest(kvm))
return -ENOTTY;
- if (sev->es_active)
- return -EPERM;
-
if (sev->handle != 0)
return -EPERM;
@@ -1242,6 +1350,13 @@ static int sev_intra_host_receive(struct kvm *kvm,
memcpy(&old_info, sev, sizeof(old_info));
+ if (entry->es_enabled) {
+ process_vmsa_list(kvm, &entry->vmsa_list);
+
+ sev->es_active = true;
+ sev->ap_jump_table = entry->ap_jump_table;
+ }
+
/*
* The source VM always frees @entry On the target we simply
* mark the token as invalid to notify the source the sev info
@@ -2034,8 +2149,16 @@ void sev_vm_destroy(struct kvm *kvm)
WARN_ON(sev->info_token && !list_empty(&sev->regions_list));
unregister_enc_regions(kvm, &sev->regions_list);
- if (mig_entry)
+ if (mig_entry) {
+ /*
+ * If there are any saved VMSAs, restore them so they can be
+ * destructed through the normal path.
+ */
+ if (mig_entry->es_enabled)
+ process_vmsa_list(kvm, &mig_entry->vmsa_list);
+
unregister_enc_regions(kvm, &mig_entry->regions_list);
+ }
mutex_unlock(&kvm->lock);
@@ -2227,9 +2350,11 @@ void sev_free_vcpu(struct kvm_vcpu *vcpu)
svm = to_svm(vcpu);
- if (vcpu->arch.guest_state_protected)
+ if (svm->ghcb && vcpu->arch.guest_state_protected)
sev_flush_guest_memory(svm, svm->vmsa, PAGE_SIZE);
- __free_page(virt_to_page(svm->vmsa));
+
+ if (svm->vmsa)
+ __free_page(virt_to_page(svm->vmsa));
if (svm->ghcb_sa_free)
kfree(svm->ghcb_sa);
--
2.32.0.432.gabb21c7263-goog
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