[PATCH V4 24/25] cpr: only-cpr-capable option

[Steve Sistare <steven.sistare@oracle.com>]

Add the only-cpr-capable option, which causes qemu to exit with an error
if any devices that are not capable of cpr are added.  This guarantees that
a cprexec operation will not fail with an unsupported device error.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
---
 MAINTAINERS             |  1 +
 chardev/char-socket.c   |  4 ++++
 hw/vfio/common.c        |  5 +++++
 hw/vfio/pci.c           |  5 +++++
 include/sysemu/sysemu.h |  1 +
 migration/migration.c   |  5 +++++
 qemu-options.hx         |  8 ++++++++
 softmmu/globals.c       |  1 +
 softmmu/physmem.c       |  4 ++++
 softmmu/vl.c            | 14 +++++++++++++-
 stubs/cpr.c             |  3 +++
 stubs/meson.build       |  1 +
 12 files changed, 51 insertions(+), 1 deletion(-)
 create mode 100644 stubs/cpr.c

diff --git a/MAINTAINERS b/MAINTAINERS
index b69bbf5..25b5bc3 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2853,6 +2853,7 @@ F: migration/cpr.c
 F: qapi/cpr.json
 F: include/qemu/env.h
 F: util/env.c
+F: stubs/cpr.c
 
 Record/replay
 M: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
diff --git a/chardev/char-socket.c b/chardev/char-socket.c
index 110f263..b8c75ff 100644
--- a/chardev/char-socket.c
+++ b/chardev/char-socket.c
@@ -40,6 +40,7 @@
 
 #include "chardev/char-io.h"
 #include "qom/object.h"
+#include "sysemu/sysemu.h"
 
 /***********************************************************/
 /* TCP Net console */
@@ -1468,6 +1469,9 @@ static void qmp_chardev_open_socket(Chardev *chr,
 
     if (!s->tls_creds && !s->is_websock) {
         qemu_chr_set_feature(chr, QEMU_CHAR_FEATURE_CPR);
+    } else if (only_cpr_capable) {
+        error_setg(errp, "error: socket %s is not cpr capable due to %s option",
+                   chr->label, (s->tls_creds ? "TLS" : "websocket"));
     }
 
     /* be isn't opened until we get a connection */
diff --git a/hw/vfio/common.c b/hw/vfio/common.c
index 40c882f..09d5e6e 100644
--- a/hw/vfio/common.c
+++ b/hw/vfio/common.c
@@ -37,6 +37,7 @@
 #include "qemu/range.h"
 #include "sysemu/kvm.h"
 #include "sysemu/reset.h"
+#include "sysemu/sysemu.h"
 #include "trace.h"
 #include "qapi/error.h"
 #include "migration/migration.h"
@@ -1601,6 +1602,10 @@ static int vfio_get_iommu_type(VFIOContainer *container,
 
     for (i = 0; i < ARRAY_SIZE(iommu_types); i++) {
         if (ioctl(container->fd, VFIO_CHECK_EXTENSION, iommu_types[i])) {
+            if (only_cpr_capable && !vfio_cpr_capable(container, errp)) {
+                error_prepend(errp, "only-cpr-capable is specified: ");
+                return -EINVAL;
+            }
             return iommu_types[i];
         }
     }
diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 492ff31..706fc0b 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -266,6 +266,11 @@ static int vfio_intx_enable(VFIOPCIDevice *vdev, Error **errp)
 
     if (!pin) {
         return 0;
+    } else if (only_cpr_capable) {
+        error_setg(errp,
+                   "%s: vfio-pci INTX is not compatible with -only-cpr-capable",
+                   vdev->vbasedev.name);
+        return -1;
     }
 
     vfio_disable_interrupts(vdev);
diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
index 8fae667..6241c20 100644
--- a/include/sysemu/sysemu.h
+++ b/include/sysemu/sysemu.h
@@ -9,6 +9,7 @@
 /* vl.c */
 
 extern int only_migratable;
+extern bool only_cpr_capable;
 extern const char *qemu_name;
 extern QemuUUID qemu_uuid;
 extern bool qemu_uuid_set;
diff --git a/migration/migration.c b/migration/migration.c
index 8ca0341..181c8d5 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -1262,6 +1262,11 @@ static bool migrate_caps_check(bool *cap_list,
         }
     }
 
+    if (cap_list[MIGRATION_CAPABILITY_X_COLO] && only_cpr_capable) {
+        error_setg(errp, "x-colo is not compatible with -only-cpr-capable");
+        return false;
+    }
+
     return true;
 }
 
diff --git a/qemu-options.hx b/qemu-options.hx
index ef2d24a..f1b372b 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -4257,6 +4257,14 @@ SRST
     an unmigratable state.
 ERST
 
+DEF("only-cpr-capable", 0, QEMU_OPTION_only_cpr_capable, \
+    "-only-cpr-capable    allow only cpr capable devices\n", QEMU_ARCH_ALL)
+SRST
+``-only-cpr-capable``
+    Only allow cpr capable devices, which guarantees that cprsave will not
+    fail with an unsupported device error.
+ERST
+
 DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \
     "-nodefaults     don't create default devices\n", QEMU_ARCH_ALL)
 SRST
diff --git a/softmmu/globals.c b/softmmu/globals.c
index 7d0fc81..a18fd8d 100644
--- a/softmmu/globals.c
+++ b/softmmu/globals.c
@@ -59,6 +59,7 @@ int boot_menu;
 bool boot_strict;
 uint8_t *boot_splash_filedata;
 int only_migratable; /* turn it off unless user states otherwise */
+bool only_cpr_capable;
 int icount_align_option;
 
 /* The bytes in qemu_uuid are in the order specified by RFC4122, _not_ in the
diff --git a/softmmu/physmem.c b/softmmu/physmem.c
index b79f408..04e3603 100644
--- a/softmmu/physmem.c
+++ b/softmmu/physmem.c
@@ -1973,6 +1973,10 @@ static void ram_block_add(RAMBlock *new_block, Error **errp, bool shared)
                 addr = file_ram_alloc(new_block, maxlen, mfd,
                                       false, false, 0, errp);
                 trace_anon_memfd_alloc(name, maxlen, addr, mfd);
+            } else if (only_cpr_capable) {
+                error_setg(errp,
+                    "only-cpr-capable requires -machine memfd-alloc=on");
+                return;
             } else {
                 addr = qemu_anon_ram_alloc(maxlen, &mr->align, shared);
             }
diff --git a/softmmu/vl.c b/softmmu/vl.c
index aadb526..78f8829 100644
--- a/softmmu/vl.c
+++ b/softmmu/vl.c
@@ -2589,6 +2589,10 @@ void qmp_x_exit_preconfig(Error **errp)
     qemu_create_cli_devices();
     qemu_machine_creation_done();
 
+    if (only_cpr_capable && !qemu_chr_cpr_capable(errp)) {
+        ;    /* not reached due to error_fatal */
+    }
+
     if (loadvm) {
         Error *local_err = NULL;
         if (!load_snapshot(loadvm, NULL, false, NULL, &local_err)) {
@@ -2598,7 +2602,12 @@ void qmp_x_exit_preconfig(Error **errp)
         }
     }
     if (replay_mode != REPLAY_MODE_NONE) {
-        replay_vmstate_init();
+        if (only_cpr_capable) {
+            error_setg(errp, "replay is not compatible with -only-cpr-capable");
+            /* not reached due to error_fatal */
+        } else {
+            replay_vmstate_init();
+        }
     }
 
     if (incoming) {
@@ -3339,6 +3348,9 @@ void qemu_init(int argc, char **argv, char **envp)
             case QEMU_OPTION_only_migratable:
                 only_migratable = 1;
                 break;
+            case QEMU_OPTION_only_cpr_capable:
+                only_cpr_capable = true;
+                break;
             case QEMU_OPTION_nodefaults:
                 has_defaults = 0;
                 break;
diff --git a/stubs/cpr.c b/stubs/cpr.c
new file mode 100644
index 0000000..aaa189e
--- /dev/null
+++ b/stubs/cpr.c
@@ -0,0 +1,3 @@
+#include "qemu/osdep.h"
+
+bool only_cpr_capable;
diff --git a/stubs/meson.build b/stubs/meson.build
index be6f6d6..2003c77 100644
--- a/stubs/meson.build
+++ b/stubs/meson.build
@@ -5,6 +5,7 @@ stub_ss.add(files('blk-exp-close-all.c'))
 stub_ss.add(files('blockdev-close-all-bdrv-states.c'))
 stub_ss.add(files('change-state-handler.c'))
 stub_ss.add(files('cmos.c'))
+stub_ss.add(files('cpr.c'))
 stub_ss.add(files('cpu-get-clock.c'))
 stub_ss.add(files('cpus-get-virtual-clock.c'))
 stub_ss.add(files('qemu-timer-notify-cb.c'))
-- 
1.8.3.1