[RFC PATCH 3/8] i386/sev: Replace LAUNCH_START ioctl with sev library equivalent

[Tyler Fanelli]

The sev library offers an equivalent API for SEV_LAUNCH_START. The
library contains some internal state for each VM it's currently running,
and organizes the internal state for each VM via it's file descriptor.
Therefore, the VM's file descriptor must be provided as input.

If this API ioctl call fails, fw_error will be set accordingly.

Signed-off-by: Tyler Fanelli <tfanelli@redhat.com>
---
 target/i386/sev.c | 80 ++++++++++++++++++-----------------------------
 1 file changed, 30 insertions(+), 50 deletions(-)

diff --git a/target/i386/sev.c b/target/i386/sev.c
index f0fd291e68..49be072cbc 100644
--- a/target/i386/sev.c
+++ b/target/i386/sev.c
@@ -715,51 +715,6 @@ sev_read_file_base64(const char *filename, guchar **data, 
gsize *len)
     return 0;
 }
 
-static int
-sev_launch_start(SevGuestState *sev)
-{
-    gsize sz;
-    int ret = 1;
-    int fw_error, rc;
-    struct kvm_sev_launch_start start = {
-        .handle = sev->handle, .policy = sev->policy
-    };
-    guchar *session = NULL, *dh_cert = NULL;
-
-    if (sev->session_file) {
-        if (sev_read_file_base64(sev->session_file, &session, &sz) < 0) {
-            goto out;
-        }
-        start.session_uaddr = (unsigned long)session;
-        start.session_len = sz;
-    }
-
-    if (sev->dh_cert_file) {
-        if (sev_read_file_base64(sev->dh_cert_file, &dh_cert, &sz) < 0) {
-            goto out;
-        }
-        start.dh_uaddr = (unsigned long)dh_cert;
-        start.dh_len = sz;
-    }
-
-    trace_kvm_sev_launch_start(start.policy, session, dh_cert);
-    rc = sev_ioctl(sev->sev_fd, KVM_SEV_LAUNCH_START, &start, &fw_error);
-    if (rc < 0) {
-        error_report("%s: LAUNCH_START ret=%d fw_error=%d '%s'",
-                __func__, ret, fw_error, fw_error_to_str(fw_error));
-        goto out;
-    }
-
-    sev_set_guest_state(sev, SEV_STATE_LAUNCH_UPDATE);
-    sev->handle = start.handle;
-    ret = 0;
-
-out:
-    g_free(session);
-    g_free(dh_cert);
-    return ret;
-}
-
 static int
 sev_launch_update_data(SevGuestState *sev, uint8_t *addr, uint64_t len)
 {
@@ -913,11 +868,13 @@ int sev_kvm_init(ConfidentialGuestSupport *cgs, Error 
**errp)
 {
     SevGuestState *sev
         = (SevGuestState *)object_dynamic_cast(OBJECT(cgs), TYPE_SEV_GUEST);
+    gsize sz;
     char *devname;
-    int ret, fw_error;
+    int ret = -1, fw_error;
     uint32_t ebx;
     uint32_t host_cbitpos;
     struct sev_user_data_status status = {};
+    guchar *session = NULL, *dh_cert = NULL;
     KVMState *s = kvm_state;
 
     if (!sev) {
@@ -1007,23 +964,46 @@ int sev_kvm_init(ConfidentialGuestSupport *cgs, Error 
**errp)
         goto err;
     }
 
-    ret = sev_launch_start(sev);
+    if (!sev->session_file || !sev->dh_cert_file) {
+        goto err;
+    }
+
+    if (sev_read_file_base64(sev->session_file, &session, &sz) < 0) {
+        goto err;
+    }
+
+    if (sev_read_file_base64(sev->dh_cert_file, &dh_cert, &sz) < 0) {
+        goto err;
+    }
+
+    ret = sev_launch_start(s->vmfd, sev->policy, (void *) dh_cert,
+                           (void *) session, &fw_error);
     if (ret) {
-        error_setg(errp, "%s: failed to create encryption context", __func__);
+        error_setg(errp, "%s: LAUNCH_START ret=%d fw_error=%d '%s'",
+                   __func__, ret, fw_error, fw_error_to_str(fw_error));
         goto err;
     }
 
+    sev_set_guest_state(sev, SEV_STATE_LAUNCH_UPDATE);
+
     ram_block_notifier_add(&sev_ram_notifier);
     qemu_add_machine_init_done_notifier(&sev_machine_done_notify);
     qemu_add_vm_change_state_handler(sev_vm_state_change, sev);
 
     cgs->ready = true;
 
-    return 0;
+    ret = 0;
+    goto out;
+
 err:
     sev_guest = NULL;
     ram_block_discard_disable(false);
-    return -1;
+out:
+    g_free(session);
+    g_free(dh_cert);
+
+    return ret;
+
 }
 
 int
-- 
2.40.1