diff --git a/target/i386/sev.c b/target/i386/sev.c
index 1296f4feb6..3e5722ba65 100644
--- a/target/i386/sev.c
+++ b/target/i386/sev.c
@@ -2518,6 +2518,88 @@ static int cgs_get_mem_map_entry(int index,
     return 0;
 }
 
+static int cgs_set_guest_policy(ConfidentialGuestPolicyType policy_type,
+                                uint64_t policy, void *policy_data1,
+                                uint32_t policy_data1_size, void *policy_data2,
+                                uint32_t policy_data2_size, Error **errp)
+{
+    if (policy_type != GUEST_POLICY_SEV) {
+        error_setg(errp, "%s: Invalid guest policy type provided for SEV: %d",
+        __func__, policy_type);
+        return -1;
+    }
+    /*
+     * SEV-SNP handles policy differently. The policy flags are defined in
+     * kvm_start_conf.policy and an ID block and ID auth can be provided.
+     */
+    if (sev_snp_enabled()) {
+        SevSnpGuestState *sev_snp_guest =
+            SEV_SNP_GUEST(MACHINE(qdev_get_machine())->cgs);
+        struct kvm_sev_snp_launch_finish *finish =
+            &sev_snp_guest->kvm_finish_conf;
+
+        /*
+         * The policy consists of flags in 'policy' and optionally an ID block
+         * and ID auth in policy_data1 and policy_data2 respectively. The ID
+         * block and auth are optional so clear any previous ID block and auth
+         * and set them if provided, but always set the policy flags.
+         */
+        g_free(sev_snp_guest->id_block);
+        g_free((guchar *)finish->id_block_uaddr);
+        g_free(sev_snp_guest->id_auth);
+        g_free((guchar *)finish->id_auth_uaddr);
+        sev_snp_guest->id_block = NULL;
+        finish->id_block_uaddr = 0;
+        sev_snp_guest->id_auth = NULL;
+        finish->id_auth_uaddr = 0;
+
+        if (policy_data1_size > 0) {
+            struct sev_snp_id_authentication *id_auth =
+                (struct sev_snp_id_authentication *)policy_data2;
+
+            if (policy_data1_size != KVM_SEV_SNP_ID_BLOCK_SIZE) {
+                error_setg(errp, "%s: Invalid SEV-SNP ID block: incorrect size",
+                           __func__);
+                return -1;
+            }
+            if (policy_data2_size != KVM_SEV_SNP_ID_AUTH_SIZE) {
+                error_setg(errp,
+                           "%s: Invalid SEV-SNP ID auth block: incorrect size",
+                           __func__);
+                return -1;
+            }
+            assert(policy_data1 != NULL);
+            assert(policy_data2 != NULL);
+
+            finish->id_block_uaddr =
+                (__u64)g_memdup2(policy_data1, KVM_SEV_SNP_ID_BLOCK_SIZE);
+            finish->id_auth_uaddr =
+                (__u64)g_memdup2(policy_data2, KVM_SEV_SNP_ID_AUTH_SIZE);
+
+            /*
+             * Check if an author key has been provided and use that to flag
+             * whether the author key is enabled. The first of the author key
+             * must be non-zero to indicate the key type, which will currently
+             * always be 2.
+             */
+            sev_snp_guest->kvm_finish_conf.auth_key_en =
+                id_auth->author_key[0] ? 1 : 0;
+            finish->id_block_en = 1;
+        }
+        sev_snp_guest->kvm_start_conf.policy = policy;
+    } else {
+        SevGuestState *sev_guest = SEV_GUEST(MACHINE(qdev_get_machine())->cgs);
+        /* Only the policy flags are supported for SEV and SEV-ES */
+        if ((policy_data1_size > 0) || (policy_data2_size > 0) || !sev_guest) {
+            error_setg(errp, "%s: An ID block/ID auth block has been provided "
+                             "but SEV-SNP is not enabled", __func__);
+            return -1;
+        }
+        sev_guest->policy = policy;
+    }
+    return 0;
+}
+
 static void
 sev_common_class_init(ObjectClass *oc, const void *data)
 {
@@ -2556,6 +2638,7 @@ sev_common_instance_init(Object *obj)
     cgs->check_support = cgs_check_support;
     cgs->set_guest_state = cgs_set_guest_state;
     cgs->get_mem_map_entry = cgs_get_mem_map_entry;
+    cgs->set_guest_policy = cgs_set_guest_policy;
 
     QTAILQ_INIT(&sev_common->launch_vmsa);
 }
diff --git a/target/i386/sev.h b/target/i386/sev.h
index d2eb06db32..9db1a802f6 100644
--- a/target/i386/sev.h
+++ b/target/i386/sev.h
@@ -167,6 +167,18 @@ struct QEMU_PACKED sev_es_save_area {
     uint8_t fpreg_ymm[256];
 };
 
+struct QEMU_PACKED sev_snp_id_authentication {
+    uint32_t id_key_alg;
+    uint32_t auth_key_algo;
+    uint8_t reserved[56];
+    uint8_t id_block_sig[512];
+    uint8_t id_key[1028];
+    uint8_t reserved2[60];
+    uint8_t id_key_sig[512];
+    uint8_t author_key[1028];
+    uint8_t reserved3[892];
+};
+
 bool sev_add_kernel_loader_hashes(SevKernelLoaderContext *ctx, Error **errp);
 
 int sev_encrypt_flash(hwaddr gpa, uint8_t *ptr, uint64_t len, Error **errp);