[PATCH v4 07/14] target/i386: sev: add support to encrypt the outgoing page

[Ashish Kalra]

From: Brijesh Singh <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>
Co-developed-by: Ashish Kalra <ashish.kalra@amd.com>
Signed-off-by: Ashish Kalra <ashish.kalra@amd.com>
---
 include/sysemu/sev.h     |   2 +
 target/i386/sev.c        | 221 +++++++++++++++++++++++++++++++++++++++
 target/i386/trace-events |   3 +
 3 files changed, 226 insertions(+)

diff --git a/include/sysemu/sev.h b/include/sysemu/sev.h
index 64fc88d3c5..aa6b91a53e 100644
--- a/include/sysemu/sev.h
+++ b/include/sysemu/sev.h
@@ -21,6 +21,8 @@ bool sev_enabled(void);
 int sev_kvm_init(ConfidentialGuestSupport *cgs, Error **errp);
 int sev_encrypt_flash(uint8_t *ptr, uint64_t len, Error **errp);
 int sev_save_setup(MigrationParameters *p);
+int sev_save_outgoing_page(QEMUFile *f, uint8_t *ptr,
+                           uint32_t size, uint64_t *bytes_sent);
 int sev_inject_launch_secret(const char *hdr, const char *secret,
                              uint64_t gpa, Error **errp);
 
diff --git a/target/i386/sev.c b/target/i386/sev.c
index 10038d3880..411bd657e8 100644
--- a/target/i386/sev.c
+++ b/target/i386/sev.c
@@ -30,6 +30,8 @@
 #include "sysemu/runstate.h"
 #include "trace.h"
 #include "migration/blocker.h"
+#include "migration/qemu-file.h"
+#include "migration/misc.h"
 #include "qom/object.h"
 #include "monitor/monitor.h"
 #include "exec/confidential-guest-support.h"
@@ -75,6 +77,8 @@ struct SevGuestState {
     size_t remote_plat_cert_len;
     guchar *amd_cert;
     size_t amd_cert_len;
+    gchar *send_packet_hdr;
+    size_t send_packet_hdr_len;
 
     uint32_t reset_cs;
     uint32_t reset_ip;
@@ -127,6 +131,7 @@ static const char *const sev_fw_errlist[] = {
 
 static struct ConfidentialGuestMemoryEncryptionOps sev_memory_encryption_ops = 
{
     .save_setup = sev_save_setup,
+    .save_outgoing_page = sev_save_outgoing_page,
 };
 
 static int
@@ -829,6 +834,40 @@ error:
     return 1;
 }
 
+static void
+sev_send_finish(void)
+{
+    int ret, error;
+
+    trace_kvm_sev_send_finish();
+    ret = sev_ioctl(sev_guest->sev_fd, KVM_SEV_SEND_FINISH, 0, &error);
+    if (ret) {
+        error_report("%s: SEND_FINISH ret=%d fw_error=%d '%s'",
+                     __func__, ret, error, fw_error_to_str(error));
+    }
+
+    g_free(sev_guest->send_packet_hdr);
+    sev_set_guest_state(sev_guest, 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_guest, SEV_STATE_SEND_UPDATE)) {
+            sev_send_finish();
+        }
+    }
+}
+
+static Notifier sev_migration_state_notify = {
+    .notify = sev_migration_state_notifier,
+};
+
 int sev_kvm_init(ConfidentialGuestSupport *cgs, Error **errp)
 {
     SevGuestState *sev
@@ -933,6 +972,7 @@ int sev_kvm_init(ConfidentialGuestSupport *cgs, Error 
**errp)
     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);
+    add_migration_state_change_notifier(&sev_migration_state_notify);
 
     cgs_class->memory_encryption_ops = &sev_memory_encryption_ops;
 
@@ -1143,6 +1183,187 @@ int sev_es_save_reset_vector(void *flash_ptr, uint64_t 
flash_size)
     return 0;
 }
 
+static int
+sev_get_send_session_length(void)
+{
+    int ret, fw_err = 0;
+    struct kvm_sev_send_start start = {};
+
+    ret = sev_ioctl(sev_guest->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:
+    return ret;
+}
+
+static int
+sev_send_start(SevGuestState *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;
+    Error *local_err = NULL;
+
+    if (!s->remote_pdh || !s->remote_plat_cert || !s->amd_cert_len) {
+        error_report("%s: missing remote PDH or PLAT_CERT", __func__);
+        return 1;
+    }
+
+   start.pdh_cert_uaddr = (uintptr_t) s->remote_pdh;
+   start.pdh_cert_len = s->remote_pdh_len;
+
+   start.plat_certs_uaddr = (uintptr_t)s->remote_plat_cert;
+   start.plat_certs_len = s->remote_plat_cert_len;
+
+   start.amd_certs_uaddr = (uintptr_t)s->amd_cert;
+   start.amd_certs_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, &local_err);
+   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_certs_uaddr, start.plat_certs_len,
+                            start.amd_certs_uaddr, start.amd_certs_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(s, SEV_STATE_SEND_UPDATE);
+
+err:
+   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 = {};
+
+    ret = sev_ioctl(sev_guest->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:
+    return ret;
+}
+
+static int
+sev_send_update_data(SevGuestState *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);
+    }
+
+    /* allocate transport buffer */
+    trans = g_new(guchar, size);
+
+    update.hdr_uaddr = (uintptr_t)s->send_packet_hdr;
+    update.hdr_len = s->send_packet_hdr_len;
+    update.guest_uaddr = (uintptr_t)ptr;
+    update.guest_len = size;
+    update.trans_uaddr = (uintptr_t)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);
+    return ret;
+}
+
+int sev_save_outgoing_page(QEMUFile *f, uint8_t *ptr,
+                           uint32_t sz, uint64_t *bytes_sent)
+{
+    SevGuestState *s = sev_guest;
+
+    /*
+     * If this is a first buffer then create outgoing encryption context
+     * and write our PDH, policy and session data.
+     */
+    if (!sev_check_state(s, 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/trace-events b/target/i386/trace-events
index 2cd8726eeb..e8d4aec125 100644
--- a/target/i386/trace-events
+++ b/target/i386/trace-events
@@ -11,3 +11,6 @@ kvm_sev_launch_measurement(const char *value) "data %s"
 kvm_sev_launch_finish(void) ""
 kvm_sev_launch_secret(uint64_t hpa, uint64_t hva, uint64_t secret, int len) 
"hpa 0x%" PRIx64 " hva 0x%" PRIx64 " data 0x%" PRIx64 " len %d"
 kvm_sev_attestation_report(const char *mnonce, const char *data) "mnonce %s 
data %s"
+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