[Qemu-devel] [RFC PATCH v1 09/12] target/i386: sev: add support to encrypt the outgoing page

["Singh, Brijesh" <brijesh.singh@amd.com>]

The sev_save_outgoing_page() provide the implementation to encrypt the
guest private pages during the transit. The routines uses the SEND_START
command to create the outgoing encryption context on the first call then
uses the SEND_UPDATE_DATA command to encrypt the data before writing it
to the socket. While encrypting the data SEND_UPDATE_DATA produces some
metadata (e.g MAC, IV). The metadata is also sent to the target machine.
After migration is completed, we issue the SEND_FINISH command to transition
the SEV guest state from sending to unrunnable state.

Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
---
 accel/kvm/kvm-all.c      |   1 +
 target/i386/sev.c        | 229 +++++++++++++++++++++++++++++++++++++++
 target/i386/sev_i386.h   |   2 +
 target/i386/trace-events |   3 +
 4 files changed, 235 insertions(+)

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 0654d9a7cd..85d6508e7f 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -1784,6 +1784,7 @@ static int kvm_init(MachineState *ms)
 
         kvm_state->memcrypt_encrypt_data = sev_encrypt_data;
         kvm_state->memcrypt_sync_page_enc_bitmap = sev_sync_page_enc_bitmap;
+        kvm_state->memcrypt_save_outgoing_page = sev_save_outgoing_page;
     }
 
     ret = kvm_arch_init(ms, s);
diff --git a/target/i386/sev.c b/target/i386/sev.c
index 2c7c496593..b5aa53ec44 100644
--- a/target/i386/sev.c
+++ b/target/i386/sev.c
@@ -27,6 +27,8 @@
 #include "sysemu/sysemu.h"
 #include "trace.h"
 #include "migration/blocker.h"
+#include "migration/qemu-file.h"
+#include "migration/misc.h"
 
 #define DEFAULT_GUEST_POLICY    0x1 /* disable debug */
 #define DEFAULT_SEV_DEVICE      "/dev/sev"
@@ -718,6 +720,39 @@ sev_vm_state_change(void *opaque, int running, RunState state)
     }
 }
 
+static void
+sev_send_finish(void)
+{
+    int ret, error;
+
+    trace_kvm_sev_send_finish();
+    ret = sev_ioctl(sev_state->sev_fd, KVM_SEV_SEND_FINISH, 0, &error);
+    if (ret) {
+        error_report("%s: LAUNCH_FINISH ret=%d fw_error=%d '%s'",
+                     __func__, ret, error, fw_error_to_str(error));
+    }
+
+    sev_set_guest_state(SEV_STATE_RUNNING);
+}
+
+static void
+sev_migration_state_notifier(Notifier *notifier, void *data)
+{
+    MigrationState *s = data;
+
+    if (migration_has_finished(s) ||
+        migration_in_postcopy_after_devices(s) ||
+        migration_has_failed(s)) {
+        if (sev_check_state(SEV_STATE_SEND_UPDATE)) {
+            sev_send_finish();
+        }
+    }
+}
+
+static Notifier sev_migration_state_notify = {
+    .notify = sev_migration_state_notifier,
+};
+
 void *
 sev_guest_init(const char *id)
 {
@@ -804,6 +839,7 @@ sev_guest_init(const char *id)
     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, s);
+    add_migration_state_change_notifier(&sev_migration_state_notify);
 
     return s;
 err:
@@ -863,6 +899,199 @@ void sev_set_migrate_info(const char *pdh, const char *plat_cert,
     s->amd_cert = g_base64_decode(amd_cert, &s->amd_cert_len);
 }
 
+static int
+sev_get_send_session_length(void)
+{
+    int ret, fw_err = 0;
+    struct kvm_sev_send_start *start;
+
+    start = g_new0(struct kvm_sev_send_start, 1);
+
+    ret = sev_ioctl(sev_state->sev_fd, KVM_SEV_SEND_START, start, &fw_err);
+    if (fw_err != SEV_RET_INVALID_LEN) {
+        ret = -1;
+        error_report("%s: failed to get session length ret=%d fw_error=%d '%s'",
+                     __func__, ret, fw_err, fw_error_to_str(fw_err));
+        goto err;
+    }
+
+    ret = start->session_len;
+err:
+    g_free(start);
+    return ret;
+}
+
+static int
+sev_send_start(SEVState *s, QEMUFile *f, uint64_t *bytes_sent)
+{
+    gsize pdh_len = 0, plat_cert_len;
+    int session_len, ret, fw_error;
+    struct kvm_sev_send_start *start;
+    guchar *pdh = NULL, *plat_cert = NULL, *session = NULL;
+
+    if (!s->remote_pdh || !s->remote_plat_cert) {
+        error_report("%s: missing remote PDH or PLAT_CERT", __func__);
+        return 1;
+    }
+
+    start = g_new0(struct kvm_sev_send_start, 1);
+
+    start->pdh_cert_uaddr = (unsigned long) s->remote_pdh;
+    start->pdh_cert_len = s->remote_pdh_len;
+
+    start->plat_cert_uaddr = (unsigned long)s->remote_plat_cert;
+    start->plat_cert_len = s->remote_plat_cert_len;
+
+    start->amd_cert_uaddr = (unsigned long)s->amd_cert;
+    start->amd_cert_len = s->amd_cert_len;
+
+    /* get the session length */
+    session_len = sev_get_send_session_length();
+    if (session_len < 0) {
+        ret = 1;
+        goto err;
+    }
+
+    session = g_new0(guchar, session_len);
+    start->session_uaddr = (unsigned long)session;
+    start->session_len = session_len;
+
+    /* Get our PDH certificate */
+    ret = sev_get_pdh_info(s->sev_fd, &pdh, &pdh_len,
+                           &plat_cert, &plat_cert_len);
+    if (ret) {
+        error_report("Failed to get our PDH cert");
+        goto err;
+    }
+
+    trace_kvm_sev_send_start(start->pdh_cert_uaddr, start->pdh_cert_len,
+                             start->plat_cert_uaddr, start->plat_cert_len,
+                             start->amd_cert_uaddr, start->amd_cert_len);
+
+    ret = sev_ioctl(s->sev_fd, KVM_SEV_SEND_START, start, &fw_error);
+    if (ret < 0) {
+        error_report("%s: SEND_START ret=%d fw_error=%d '%s'",
+                __func__, ret, fw_error, fw_error_to_str(fw_error));
+        goto err;
+    }
+
+    qemu_put_be32(f, start->policy);
+    qemu_put_be32(f, pdh_len);
+    qemu_put_buffer(f, (uint8_t *)pdh, pdh_len);
+    qemu_put_be32(f, start->session_len);
+    qemu_put_buffer(f, (uint8_t *)start->session_uaddr, start->session_len);
+    *bytes_sent = 12 + pdh_len + start->session_len;
+
+    sev_set_guest_state(SEV_STATE_SEND_UPDATE);
+
+err:
+    g_free(start);
+    g_free(pdh);
+    g_free(plat_cert);
+    return ret;
+}
+
+static int
+sev_send_get_packet_len(int *fw_err)
+{
+    int ret;
+    struct kvm_sev_send_update_data *update;
+
+    update = g_malloc0(sizeof(*update));
+    if (!update) {
+        return -1;
+    }
+
+    ret = sev_ioctl(sev_state->sev_fd, KVM_SEV_SEND_UPDATE_DATA, update, fw_err);
+    if (*fw_err != SEV_RET_INVALID_LEN) {
+        ret = -1;
+        error_report("%s: failed to get session length ret=%d fw_error=%d '%s'",
+                    __func__, ret, *fw_err, fw_error_to_str(*fw_err));
+        goto err;
+    }
+
+    ret = update->hdr_len;
+
+err:
+    g_free(update);
+    return ret;
+}
+
+static int
+sev_send_update_data(SEVState *s, QEMUFile *f, uint8_t *ptr, uint32_t size,
+                     uint64_t *bytes_sent)
+{
+    int ret, fw_error;
+    guchar *trans;
+    struct kvm_sev_send_update_data *update;
+
+    /* If this is first call then query the packet header bytes and allocate
+     * the packet buffer.
+     */
+    if (!s->send_packet_hdr) {
+        s->send_packet_hdr_len = sev_send_get_packet_len(&fw_error);
+        if (s->send_packet_hdr_len < 1) {
+            error_report("%s: SEND_UPDATE fw_error=%d '%s'",
+                    __func__, fw_error, fw_error_to_str(fw_error));
+            return 1;
+        }
+
+        s->send_packet_hdr = g_new(gchar, s->send_packet_hdr_len);
+    }
+
+    update = g_new0(struct kvm_sev_send_update_data, 1);
+
+    /* allocate transport buffer */
+    trans = g_new(guchar, size);
+
+    update->hdr_uaddr = (unsigned long)s->send_packet_hdr;
+    update->hdr_len = s->send_packet_hdr_len;
+    update->guest_uaddr = (unsigned long)ptr;
+    update->guest_len = size;
+    update->trans_uaddr = (unsigned long)trans;
+    update->trans_len = size;
+
+    trace_kvm_sev_send_update_data(ptr, trans, size);
+
+    ret = sev_ioctl(s->sev_fd, KVM_SEV_SEND_UPDATE_DATA, update, &fw_error);
+    if (ret) {
+        error_report("%s: SEND_UPDATE_DATA ret=%d fw_error=%d '%s'",
+                __func__, ret, fw_error, fw_error_to_str(fw_error));
+        goto err;
+    }
+
+    qemu_put_be32(f, update->hdr_len);
+    qemu_put_buffer(f, (uint8_t *)update->hdr_uaddr, update->hdr_len);
+    *bytes_sent = 4 + update->hdr_len;
+
+    qemu_put_be32(f, update->trans_len);
+    qemu_put_buffer(f, (uint8_t *)update->trans_uaddr, update->trans_len);
+    *bytes_sent += (4 + update->trans_len);
+
+err:
+    g_free(trans);
+    g_free(update);
+    return ret;
+}
+
+int sev_save_outgoing_page(void *handle, QEMUFile *f, uint8_t *ptr,
+                           uint32_t sz, uint64_t *bytes_sent)
+{
+    SEVState *s = sev_state;
+
+    /*
+     * If this is a first buffer then create outgoing encryption context
+     * and write our PDH, policy and session data.
+     */
+    if (!sev_check_state(SEV_STATE_SEND_UPDATE) &&
+        sev_send_start(s, f, bytes_sent)) {
+        error_report("Failed to create outgoing context");
+        return 1;
+    }
+
+    return sev_send_update_data(s, f, ptr, sz, bytes_sent);
+}
+
 static void
 sev_register_types(void)
 {
diff --git a/target/i386/sev_i386.h b/target/i386/sev_i386.h
index 258047ab2c..38893fb1fa 100644
--- a/target/i386/sev_i386.h
+++ b/target/i386/sev_i386.h
@@ -88,6 +88,8 @@ struct SEVState {
     size_t remote_plat_cert_len;
     guchar *amd_cert;
     size_t amd_cert_len;
+    gchar *send_packet_hdr;
+    size_t send_packet_hdr_len;
 };
 
 typedef struct SEVState SEVState;
diff --git a/target/i386/trace-events b/target/i386/trace-events
index 789c700d4a..b41516cf9f 100644
--- a/target/i386/trace-events
+++ b/target/i386/trace-events
@@ -15,3 +15,6 @@ kvm_sev_launch_start(int policy, void *session, void *pdh) "policy 0x%x session
 kvm_sev_launch_update_data(void *addr, uint64_t len) "addr %p len 0x%" PRIu64
 kvm_sev_launch_measurement(const char *value) "data %s"
 kvm_sev_launch_finish(void) ""
+kvm_sev_send_start(uint64_t pdh, int l1, uint64_t plat, int l2, uint64_t amd, int l3) "pdh 0x%" PRIx64 " len %d plat 0x%" PRIx64 " len %d amd 0x%" PRIx64 " len %d"
+kvm_sev_send_update_data(void *src, void *dst, int len) "guest %p trans %p len %d"
+kvm_sev_send_finish(void) ""
-- 
2.17.1